Speaker distortion

[John O'Flaherty]

Hello all,

I did some tests on speakers I use for a digital piano, and find that
they have ~10% distortion @ 90 dB spl. I would like to get some better
speakers, maybe studio monitors. I find a lot of these with claims of
"low distortion", but none so far with actual specifications. The few
units that have a distortion spec are powered units, with distortion
of a fraction of a percent, which probably applies to the amplifier
only. Do any speaker manufacturers provide distortion figures for
their speakers, or is there a review source where someone else has
tested them?

--
John

[Wecan do it]

What kind of distortion? How was this measured? Anything
outside of an anechoic chamber should be questionable. 10%
sounds about right to me a speaker builder for years.

If the freq response is off by 6dB at the bottom end does that
mean there is distortion down there? If you put your test freq
right in the middle of the crossover and the frequencies in
the crossover region do not phase exactly because they are
coming from two drivers is that distortion?

Peace
dawg





"John O'Flaherty" > wrote in message
...
> Hello all,
>
> I did some tests on speakers I use for a digital piano, and
> find that
> they have ~10% distortion @ 90 dB spl. I would like to get
> some better
> speakers, maybe studio monitors. I find a lot of these with
> claims of
> "low distortion", but none so far with actual
> specifications. The few
> units that have a distortion spec are powered units, with
> distortion
> of a fraction of a percent, which probably applies to the
> amplifier
> only. Do any speaker manufacturers provide distortion
> figures for
> their speakers, or is there a review source where someone
> else has
> tested them?
>
> --
> John

[Richard Crowley]

John O'Flaherty wrote:
> I did some tests on speakers I use for a digital piano, and find that
> they have ~10% distortion @ 90 dB spl. I would like to get some better
> speakers, maybe studio monitors. I find a lot of these with claims of
> "low distortion", but none so far with actual specifications. The few
> units that have a distortion spec are powered units, with distortion
> of a fraction of a percent, which probably applies to the amplifier
> only. Do any speaker manufacturers provide distortion figures for
> their speakers, or is there a review source where someone else has
> tested them?

The reason speaker manufacturers don't quote distortion numbers
is because none of them look very good. 10% actually seems pretty
good depending on what kind of speakers you are talking about
(which you didn't disclose).

You also didn't reveal WHY you want to get some better speakers.
If you want better speakers because you tested yours at 10%, then
don't bother. You can't correlate distortion % (or even frequency
response) with how speakers SOUND in real-world applications.

You also didn't reveal HOW you made the distortion measurements.
Bonus question: How much distortion is there in a real piano?

[John O'Flaherty]

>"John O'Flaherty" > wrote in message
...
>> Hello all,
>>
>> I did some tests on speakers I use for a digital piano, and
>> find that
>> they have ~10% distortion @ 90 dB spl. I would like to get
>> some better
>> speakers, maybe studio monitors. I find a lot of these with
>> claims of
>> "low distortion", but none so far with actual
>> specifications. The few
>> units that have a distortion spec are powered units, with
>> distortion
>> of a fraction of a percent, which probably applies to the
>> amplifier
>> only. Do any speaker manufacturers provide distortion
>> figures for
>> their speakers, or is there a review source where someone
>> else has
>> tested them?

On Sat, 10 Oct 2009 10:40:33 -0400, "Wecan do it"
> wrote:

>What kind of distortion? How was this measured? Anything
>outside of an anechoic chamber should be questionable. 10%
>sounds about right to me a speaker builder for years.
>
>If the freq response is off by 6dB at the bottom end does that
>mean there is distortion down there? If you put your test freq
>right in the middle of the crossover and the frequencies in
>the crossover region do not phase exactly because they are
>coming from two drivers is that distortion?

First, let me correct what I stated as the distortion - it's
something I did a couple of months ago, and I mis-remembered 10 db as
10%. The actual distortion was more like 30%. I'm referring to
non-linear distortion, in this case odd-harmonic, particularly third.

Context: the speakers I'm using are two old (1960s) AR-5 speaker
boxes that I inherited with kicked-in drivers. The drivers were
replaced with physically similar Radio Shack units - which were
cheaply available in the 70s, when I installed them.

The distortion measurement was made like this:
The left/right units were tested individually. The microphone used
was the 1 inch electrostatic unit in an old General Radio 1565-B SPL
meter at about two feet from the driver in question. This meter
provided the SPL measurement. It has an output jack after the first
stage of amplification, and this output was fed into the auxiliary
input of a computer sound card.

A program called Spectrogram 16 was used to view the amplitude vs.
frequency spectrum. The speakers were excited by a series of pure sine
test tones from the computer sound card. The results were similar for
most midband frequencies - the third harmonic of the test tone was
about 10 db down from the fundamental, which comes to 30% distortion.*

To verify the whole setup, I attached an 8 ohm resistor to the
amplifier output, and did the same test with the speakers and
microphone out of the path. No significant distortion was detectable
from the amplifer or the rest of the test setup - all harmonic peaks
of the test tones were down in the noise. This still leaves the
microphone and SPL meter untested, but the speakers seem a more likely
source of distortion than the SPL meter, especially since 90 dB SPL is
well below the 140 dB range of the meter. On the other hand I didn't
use the same setup on any better speakers, so I guess some distortion
could still be due to the meter.

Finally, it seems like an anechoic chamber would be needed for
frequency response measurements, but I don't think it's so important
for near-field distortion measurements, especially if the distortion
was similar for test tones at multiple frequencies.

--
John


*distortion % from dB: 10^(-10db/20)
dB from distortion %: 20 * log10(.3) = -10dB

[Don Pearce]

On Sat, 10 Oct 2009 09:28:09 -0700, "Richard Crowley"
> wrote:

>John O'Flaherty wrote:
>> I did some tests on speakers I use for a digital piano, and find that
>> they have ~10% distortion @ 90 dB spl. I would like to get some better
>> speakers, maybe studio monitors. I find a lot of these with claims of
>> "low distortion", but none so far with actual specifications. The few
>> units that have a distortion spec are powered units, with distortion
>> of a fraction of a percent, which probably applies to the amplifier
>> only. Do any speaker manufacturers provide distortion figures for
>> their speakers, or is there a review source where someone else has
>> tested them?
>
>The reason speaker manufacturers don't quote distortion numbers
>is because none of them look very good. 10% actually seems pretty
>good depending on what kind of speakers you are talking about
>(which you didn't disclose).
>
>You also didn't reveal WHY you want to get some better speakers.
>If you want better speakers because you tested yours at 10%, then
>don't bother. You can't correlate distortion % (or even frequency
>response) with how speakers SOUND in real-world applications.
>
>You also didn't reveal HOW you made the distortion measurements.
>Bonus question: How much distortion is there in a real piano?
>

A piano is a source, not a reproducer. It is by definition
distortion-free. All the harmonics are wanted.

Having said that, I would say that 10% distortion is horribly high
even for speakers.

d
--
Pearce Consulting
http://www.pearce.uk.com

[John O'Flaherty]

On Sat, 10 Oct 2009 09:28:09 -0700, "Richard Crowley"
> wrote:

>John O'Flaherty wrote:
>> I did some tests on speakers I use for a digital piano, and find that
>> they have ~10% distortion @ 90 dB spl. I would like to get some better
>> speakers, maybe studio monitors. I find a lot of these with claims of
>> "low distortion", but none so far with actual specifications. The few
>> units that have a distortion spec are powered units, with distortion
>> of a fraction of a percent, which probably applies to the amplifier
>> only. Do any speaker manufacturers provide distortion figures for
>> their speakers, or is there a review source where someone else has
>> tested them?
>
>The reason speaker manufacturers don't quote distortion numbers
>is because none of them look very good. 10% actually seems pretty
>good depending on what kind of speakers you are talking about
>(which you didn't disclose).
>
>You also didn't reveal WHY you want to get some better speakers.
>If you want better speakers because you tested yours at 10%, then
>don't bother. You can't correlate distortion % (or even frequency
>response) with how speakers SOUND in real-world applications.
>
>You also didn't reveal HOW you made the distortion measurements.
>Bonus question: How much distortion is there in a real piano?

I disclosed how I tested in another reply, and I misquoted the figure
- it was 30%. For your last question, there is no distortion in a real
piano, by definition. It's a given, and it's good enough for piano
works, anyhow.
Seriously, I want new speakers to make the digital piano I have sound
more like a real piano. I use it as itself and as a midi controller
for software pianos; I'm not sure what part of the deficiency is due
to distortion. I want it to sound good in the room, so I'm not
interested in headphones. The speakers I have are very old and I'd
like to replace them, but if I'm going to drop 1k$ or so, I'd like to
know that what I'm buying isn't just junk.
--
John

[Laurence Payne[_2_]]

On Sat, 10 Oct 2009 09:20:31 -0500, John O'Flaherty
> wrote:

>Hello all,
>
> I did some tests on speakers I use for a digital piano, and find that
>they have ~10% distortion @ 90 dB spl. I would like to get some better
>speakers, maybe studio monitors. I find a lot of these with claims of
>"low distortion", but none so far with actual specifications. The few
>units that have a distortion spec are powered units, with distortion
>of a fraction of a percent, which probably applies to the amplifier
>only. Do any speaker manufacturers provide distortion figures for
>their speakers, or is there a review source where someone else has
>tested them?

The piano sound is VERY peaky and is notorious for overloading
speakers in a nasty way. (A snare drum hit does it too, but the
distortion doesn't sound so bad on that sound.) You maybe don't need
better numbers, just bigger speakers. Or play softer.

[Laurence Payne[_2_]]

On Sat, 10 Oct 2009 17:04:57 GMT, (Don Pearce)
wrote:

>>Bonus question: How much distortion is there in a real piano?
>>
>
>A piano is a source, not a reproducer. It is by definition
>distortion-free. All the harmonics are wanted.

That's an engineer's answer. Musicians know that pianos can distort,
acoustically, with never a mic, amp or speaker in sight.

[Don Pearce]

On Sat, 10 Oct 2009 18:24:42 +0100, Laurence Payne
> wrote:

>On Sat, 10 Oct 2009 17:04:57 GMT, (Don Pearce)
>wrote:
>
>>>Bonus question: How much distortion is there in a real piano?
>>>
>>
>>A piano is a source, not a reproducer. It is by definition
>>distortion-free. All the harmonics are wanted.
>
>That's an engineer's answer. Musicians know that pianos can distort,
>acoustically, with never a mic, amp or speaker in sight.

Prepared piano - distorted or not?

(BTW, I know you are right really).

d
--
Pearce Consulting
http://www.pearce.uk.com

[Richard Crowley]

John O'Flaherty wrote:
> Seriously, I want new speakers to make the digital piano I have
> sound more like a real piano.

You have a decision of whether to get something that makes *that
piano* sound like you think it should, or alternately speakers that
are as accurate as your budget and your room allow and then you
can hear how good your piano synth really is. :-)

Maybe you can get both in one speaker. Do you live somewhere
where you can go and hear various speakers (ideally side by side)?
Or even better, a way to get speakers for audition at home?

Make a CD of your piano and take it along when you visit other
places (shops, studios, friend's homes, etc.) and try playing on
various speakers to see how you like them.

There have been profitable discussions of how to select speakers
and which brands/models are generally regarded as good. If the
Google Groups archive is operating these days, maybe you can
find some of those discussions. They are worth taking a couple
of hours to review.

Selecting speakers by "specifications" without hearing them is
practically guaranteed to failure and disappointment.

[Jay Ts]

> John O'Flaherty wrote:
>> Seriously, I want new speakers to make the digital piano
>> I have sound more like a real piano.

Since you mentioned a budget of about $1000, my first suggestion
is that you start off by getting a decent pair of studio monitor
headphones. The reason is simply that you can do that for about
1/10 the price of the new monitors, and the headphones will help
you discern what your instrument is supposed to sound like, and
help you recognize the "right" speakers when you hear them.

Different models of headphones sound very different from each other,
too, so the idea is to get "in the ballpark", rather than to get a
perfect, undistorted sound. The headphones I have here are old
models, that either are now unavailable or aren't as good as currently-
available models, so I'll tell you what's on my wishlist: Audio Technica
ATH-M50's (about $150), or maybe Sennheiser HD280Pro's (about $100).
These are both based on good things people have said about them here,
and please take that as a suggestion, not a recommendation.

Richard Crowley wrote:
> Do you live somewhere where you
> can go and hear various speakers (ideally side by side)? Or even better,
> a way to get speakers for audition at home?
>
> Make a CD of your piano and take it along when you visit other places
> (shops, studios, friend's homes, etc.) and try playing on various
> speakers to see how you like them.
>
> There have been profitable discussions of how to select speakers and
> which brands/models are generally regarded as good. If the Google Groups
> archive is operating these days, maybe you can find some of those
> discussions. They are worth taking a couple of hours to review.
>
> Selecting speakers by "specifications" without hearing them is
> practically guaranteed to failure and disappointment.

I completely agree with Richard here. DO NOT buy speakers "blind"
(really, deaf :). Make sure you listen to at least a few models before
purchasing, using whatever method you can.

When I last bought studio monitors, I did the most extensive
research on the net that I possibly could, and all that did
was prepare me to drive to a big city, 2 hours away, where I
could actually listen to the monitors on my short list.

The products had very similar specs, but in reality sounded
VERY different from each other. I was operating on a very small
budget, and got a pair of Event 20/20's for just $300. That was
over 10 years ago, and although I could use an upgrade, I'm
still very happy with them.

In retrospect, I'm glad I only had to drive 2 hours to do the
listening tests.

Jay Ts
--
To contact me, use this web page:
http://www.jayts.com/contact.php

[David Gravereaux]

In general, compression drivers for mid and high range have excellent
distortion specs when connected to a proper horn. Also, folded horn
subs, but the range below 80Hz probably is of no interest to you. From
all the distortion vs. frequency graphs I've seen for loudspeakers, 3rd
harmonic is quite predominant for the woofers due to the fact they have
to travel. Ported ones are worse than acoustic suspension due to port
whistles.

Advice? Well, you'll blow the $1000 right off on a pair of
Electro-Voice ND6-8 drivers, a pair of ADH-6 adapters, and a pair of
HP940 horns and that's just 1000Hz and up. Mid-bass (assuming 80Hz is
your F3), processor and amps are missing... hmm.

But that's the cream of the crop. Although the semi-pro market doesn't
offer much in the way of horn loaded anything, you *might* consider DIY
to keep the cost down. Maybe even just replace your tweeter with
something like this:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=280-050
Now bi-amp the system and use a descent processor like a DBX DriveRackPA
or a Behringer DCX2496 and grab a friend with a MLSSA rig to setup the
EQ for you with the $700 you've saved.

Next, if your mids are still yucky, consider some mid-horns. You could
even build those. One high efficiency 12" like an Eminence Delta
Pro-12A on a tractrix horn ought to make 105dB(SPL)/1W/1M
--



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[Eric B[_2_]]

It seems like no one is getting close to answering the question
Piano, being a wide spectrum, percussive instrument, will push against
and reveal various issues with speakers more than many other sources.
These issues include the limitations of the tweeter, the distortion
inherent in crossovers and the physical fact that there are two
drivers to some extent putting out the same information which results
in phase cancelation as they combine in the room, and lastly that
vented boxes always loose it both at and below the note they are tuned
to.
Almost all speakers say they are accurate and have low distortion.
The advice that you go listen to a number of speakers is valid. On the
other hand, there are a few things that I suggest you should know
about before doing that. Some of these are opinion, based on my
experience and my sense of 'taste'. Most hifi speakers are intended
to be used for program material which has been compressed. They can
not handle the peaks that pianos are capable of.
In order to handle the bass that pianos are capable of, the low end
has to be solid. I recommend acoustic suspension; ie not vented. The
woofer has to be solid, have wide excursion and be able to handle more
power than hifi. The cabinet ought to be massive (heavy) enough that
the deeper bass doesn't come apart at higher volumes. The crossover
ought to be low order, 6db/ova preferably. This is also a matter of
taste, but again based on some experience. 18 to 24 db/ova xovers are
popular because they let the designers use components with less power
handling or frequency range. In theory the steeper slopes mean less of
the cross over range is multi-sourced, in practice 24 db/ova
crossovers result in the high frequency component being back a full
cycle. The tweeter ought to be over built, better than minimal,
because piano puts out very strong peaks. Compression drivers on horns
have a particular sound, dome tweeters are more accurate but have
volume and power handling limitations. A few compression drivers on
shallower constant directivity horns aren't too ugly, most horns have
throat distortion that will be audible with a good piano.
Most of this is not information that shows up in the specs. Almost
nobody uses acoustic suspension because the market wants strong bass
rather than accurate bass.
A few brands to look at Dynaudio, ADAM, NHT, BlueSky, I wish I had
more time to look at what is available these days. This post is rushed
because I've got places to go. I hope it helps. Feel free to contact
me off group.
Where are you located? What retail outlets are available to you to
listen.
Powered monitors are often the best way to go these days. Even the
Mackies, which I don't like, are pretty good.
I own an old pair of Celestion SL6s that would reproduce piano
fairly well, but with limited max spl. I also have an old pair of TOA
speakers that are good for what you are doing.
Later,
Eric B

[John O'Flaherty]

On Sat, 10 Oct 2009 23:21:34 -0700, David Gravereaux
> wrote:

>In general, compression drivers for mid and high range have excellent
>distortion specs when connected to a proper horn. Also, folded horn
>subs, but the range below 80Hz probably is of no interest to you. From
>all the distortion vs. frequency graphs I've seen for loudspeakers, 3rd
>harmonic is quite predominant for the woofers due to the fact they have
>to travel. Ported ones are worse than acoustic suspension due to port
>whistles.
>
>Advice? Well, you'll blow the $1000 right off on a pair of
>Electro-Voice ND6-8 drivers, a pair of ADH-6 adapters, and a pair of
>HP940 horns and that's just 1000Hz and up. Mid-bass (assuming 80Hz is
>your F3), processor and amps are missing... hmm.
>
>But that's the cream of the crop. Although the semi-pro market doesn't
>offer much in the way of horn loaded anything, you *might* consider DIY
>to keep the cost down. Maybe even just replace your tweeter with
>something like this:
> http://www.parts-express.com/pe/showdetl.cfm?Partnumber=280-050
>Now bi-amp the system and use a descent processor like a DBX DriveRackPA
>or a Behringer DCX2496 and grab a friend with a MLSSA rig to setup the
>EQ for you with the $700 you've saved.
>
>Next, if your mids are still yucky, consider some mid-horns. You could
>even build those. One high efficiency 12" like an Eminence Delta
>Pro-12A on a tractrix horn ought to make 105dB(SPL)/1W/1M

Apart from the distortion question, is there some kind of high
mechanical impedance driver that could excite a piece of wood like a
sound board?

Thanks to all for the suggestions. I guess, then, nobody publishes
distortion specs.

--
John

[Don Pearce[_3_]]

On Sun, 11 Oct 2009 08:59:47 -0500, John O'Flaherty
> wrote:

>On Sat, 10 Oct 2009 23:21:34 -0700, David Gravereaux
> wrote:
>
>>In general, compression drivers for mid and high range have excellent
>>distortion specs when connected to a proper horn. Also, folded horn
>>subs, but the range below 80Hz probably is of no interest to you. From
>>all the distortion vs. frequency graphs I've seen for loudspeakers, 3rd
>>harmonic is quite predominant for the woofers due to the fact they have
>>to travel. Ported ones are worse than acoustic suspension due to port
>>whistles.
>>
>>Advice? Well, you'll blow the $1000 right off on a pair of
>>Electro-Voice ND6-8 drivers, a pair of ADH-6 adapters, and a pair of
>>HP940 horns and that's just 1000Hz and up. Mid-bass (assuming 80Hz is
>>your F3), processor and amps are missing... hmm.
>>
>>But that's the cream of the crop. Although the semi-pro market doesn't
>>offer much in the way of horn loaded anything, you *might* consider DIY
>>to keep the cost down. Maybe even just replace your tweeter with
>>something like this:
>> http://www.parts-express.com/pe/showdetl.cfm?Partnumber=280-050
>>Now bi-amp the system and use a descent processor like a DBX DriveRackPA
>>or a Behringer DCX2496 and grab a friend with a MLSSA rig to setup the
>>EQ for you with the $700 you've saved.
>>
>>Next, if your mids are still yucky, consider some mid-horns. You could
>>even build those. One high efficiency 12" like an Eminence Delta
>>Pro-12A on a tractrix horn ought to make 105dB(SPL)/1W/1M
>
>Apart from the distortion question, is there some kind of high
>mechanical impedance driver that could excite a piece of wood like a
>sound board?
>
>Thanks to all for the suggestions. I guess, then, nobody publishes
>distortion specs.

Quad do, at least. The current product is specified as 0.15% at 100dB
SPL above 1kHz. It gets a little greater at lower frequencies.

d

[Scott Dorsey]

John O'Flaherty > wrote:
> I did some tests on speakers I use for a digital piano, and find that
>they have ~10% distortion @ 90 dB spl. I would like to get some better
>speakers, maybe studio monitors. I find a lot of these with claims of
>"low distortion", but none so far with actual specifications. The few
>units that have a distortion spec are powered units, with distortion
>of a fraction of a percent, which probably applies to the amplifier
>only. Do any speaker manufacturers provide distortion figures for
>their speakers, or is there a review source where someone else has
>tested them?

There are no speakers with low distortion. In general, the things people
do to increase directivity (which increases efficiency) will increase
distortion. In general, distortion at low frequencies is higher than
distortion at high frequencies. In general, nobody will give you a distortion
spec on a loudspeaker because there is no standard way of measuring it.

Seeing as how there are no low distortion speakers out there, your goal often
becomes a job of juggling different kinds of distortion and finding the least
offensive kind.

What don't you like about the sound of the speakers you have?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

John O'Flaherty > wrote:
> First, let me correct what I stated as the distortion - it's
>something I did a couple of months ago, and I mis-remembered 10 db as
>10%. The actual distortion was more like 30%. I'm referring to
>non-linear distortion, in this case odd-harmonic, particularly third.

That's godawful.

> Context: the speakers I'm using are two old (1960s) AR-5 speaker
>boxes that I inherited with kicked-in drivers. The drivers were
>replaced with physically similar Radio Shack units - which were
>cheaply available in the 70s, when I installed them.

That's godawful.

> The distortion measurement was made like this:
> The left/right units were tested individually. The microphone used
>was the 1 inch electrostatic unit in an old General Radio 1565-B SPL
>meter at about two feet from the driver in question. This meter
>provided the SPL measurement. It has an output jack after the first
>stage of amplification, and this output was fed into the auxiliary
>input of a computer sound card.

This makes about sense, but you're measuring godawful speakers and getting
a godawful number.

There are no low distortion speakers made, but there are plenty out there
that are not godawful. Just about anything available at your local MI
store is going to perform better than an AR cabinet with random ****ty
RS drivers in it.

You might consider the powered Mackies, for instance.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Laurence Payne > wrote:
>On Sat, 10 Oct 2009 17:04:57 GMT, (Don Pearce)
>wrote:
>
>>>Bonus question: How much distortion is there in a real piano?
>>>
>>
>>A piano is a source, not a reproducer. It is by definition
>>distortion-free. All the harmonics are wanted.
>
>That's an engineer's answer. Musicians know that pianos can distort,
>acoustically, with never a mic, amp or speaker in sight.

Have the tech fiddle with the damping until it stops.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Sean Conolly]

"John O'Flaherty" > wrote in message
...

> Seriously, I want new speakers to make the digital piano I have sound
> more like a real piano. I use it as itself and as a midi controller
> for software pianos; I'm not sure what part of the deficiency is due
> to distortion. I want it to sound good in the room, so I'm not
> interested in headphones. The speakers I have are very old and I'd
> like to replace them, but if I'm going to drop 1k$ or so, I'd like to
> know that what I'm buying isn't just junk.

So to me it sounds like the real question is "what are some good
speakers/monitors up to $1K for a set?". I personally like the Mackie 824s
and the Blue Sky System One, but those may be a little higher than your
budget.

Sean

[David Gravereaux]

John O'Flaherty wrote:
...
> Thanks to all for the suggestions. I guess, then, nobody publishes
> distortion specs.
>

Few do. It's like the elephant in the room no one talks about. Same
for probably dispersion angle, too.

--



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[David Gravereaux]

Eric B wrote:
...
> In order to handle the bass that pianos are capable of, the low end
> has to be solid. I recommend acoustic suspension; ie not vented. The
> woofer has to be solid, have wide excursion and be able to handle more
> power than hifi.

You'd be surprised, but folded horns have much lower distortion than
acoustic suspension when done right. Mostly for the reason they move
less due to better coupling to the air. An AS is like a ten-speed bike
in first gear, you have to move a lot to produce work whereas a horn is
like you're in fifth gear and can push harder (pressure) yet move less.
The downside is, of course, size. A high excursion 15" driver in a
relatively small 340 liter box and properly EQ'd will get you 28Hz.
Take a slightly different tuned driver and place it in something like a
15' path length horn tuned for 28Hz and you'll have way less distortion
because the driver has an acoustic transformer to push against. Folding
15' into a cabinet would be something like this:
http://billfitzmaurice.net/THT.html

But horns are unpopular and you have to watch appearances these days.
--



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[David Gravereaux]

David Gravereaux wrote:

> http://billfitzmaurice.net/THT.html

"
20Hz: 114dB at 4.5% THD. I did not push any further, as the panes in my
windows were moving about 1/16" at the time. I think they would have
broken if I went further.
"
--



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[hank alrich]

Scott Dorsey > wrote:

> Laurence Payne > wrote:
> >On Sat, 10 Oct 2009 17:04:57 GMT, (Don Pearce)
> >wrote:
> >
> >>>Bonus question: How much distortion is there in a real piano?
> >>>
> >>
> >>A piano is a source, not a reproducer. It is by definition
> >>distortion-free. All the harmonics are wanted.
> >
> >That's an engineer's answer. Musicians know that pianos can distort,
> >acoustically, with never a mic, amp or speaker in sight.
>
> Have the tech fiddle with the damping until it stops.
> --scott

You can often drive a piano into distortion just by how hard you hit the
keys.

--
ha
shut up and play your guitar

[Geoff]

Laurence Payne wrote:
> On Sat, 10 Oct 2009 17:04:57 GMT, (Don Pearce)
> wrote:
>
>>> Bonus question: How much distortion is there in a real piano?
>>>
>>
>> A piano is a source, not a reproducer. It is by definition
>> distortion-free. All the harmonics are wanted.
>
> That's an engineer's answer. Musicians know that pianos can distort,
> acoustically, with never a mic, amp or speaker in sight.

That distortion *is* the piano.

geoff

[Laurence Payne[_2_]]

On Sun, 11 Oct 2009 11:12:31 -0400, "Sean Conolly"
> wrote:

>So to me it sounds like the real question is "what are some good
>speakers/monitors up to $1K for a set?". I personally like the Mackie 824s
>and the Blue Sky System One, but those may be a little higher than your
>budget.

The 824's certainly handle piano well, for medium-small speakers.

[Laurence Payne[_2_]]

On Mon, 12 Oct 2009 10:21:14 +1300, "geoff" >
wrote:

>> That's an engineer's answer. Musicians know that pianos can distort,
>> acoustically, with never a mic, amp or speaker in sight.
>
>That distortion *is* the piano.

Yup. And you can play and/or adjust it in a way that make bad sounds.
Distorted music.

[Geoff]

Laurence Payne wrote:
> On Mon, 12 Oct 2009 10:21:14 +1300, "geoff" >
> wrote:
>
>>> That's an engineer's answer. Musicians know that pianos can
>>> distort, acoustically, with never a mic, amp or speaker in sight.
>>
>> That distortion *is* the piano.
>
> Yup. And you can play and/or adjust it in a way that make bad sounds.
> Distorted music.

There is distortion that is a part of the instrument or music, and
distortion resulting from the playback media or mechanism. The line between
which is which should not be blurred (or distorted) as they are completely
separate issues - well one is an issue, and the other is not.

geoff

[William Sommerwerck]

Anyone concerned with accurate piano reproduction should remember that piano
recordings are often muy malo.

[Sebastian Z u e n d o r f]

(Scott Dorsey) wrote:

>You might consider the powered Mackies, for instance.

The older SRM-series was about ok - the new ones are godawful, though.

Sebastian


--
F: Was ist ein Mathematiker?
A: Ein Gerät das Kaffee in Behauptungen umwandelt.

Die Partyband vom Niederrhein: http://www.stimmtso.net

[hank alrich]

geoff > wrote:

> Laurence Payne wrote:
> > On Mon, 12 Oct 2009 10:21:14 +1300, "geoff" >
> > wrote:
> >
> >>> That's an engineer's answer. Musicians know that pianos can
> >>> distort, acoustically, with never a mic, amp or speaker in sight.
> >>
> >> That distortion *is* the piano.
> >
> > Yup. And you can play and/or adjust it in a way that make bad sounds.
> > Distorted music.
>
> There is distortion that is a part of the instrument or music, and
> distortion resulting from the playback media or mechanism. The line between
> which is which should not be blurred (or distorted) as they are completely
> separate issues - well one is an issue, and the other is not.
>
> geoff

Well said. I have a truly wonderful acoustic guitar, made for me by the
late Lance McCollum. I can get really clean out of it, or I can drive it
into distortion just by how I attack the strings.

Same for the 1921 Chickering grand here, and I'm no real piano player.

Riley Osbourn can make it seem like smoke is about to come out of a
piano.

--
ha
shut up and play your guitar

[Les Cargill[_2_]]

hank alrich wrote:
> Scott Dorsey > wrote:
>
>> Laurence Payne > wrote:
>>> On Sat, 10 Oct 2009 17:04:57 GMT, (Don Pearce)
>>> wrote:
>>>
>>>>> Bonus question: How much distortion is there in a real piano?
>>>>>
>>>> A piano is a source, not a reproducer. It is by definition
>>>> distortion-free. All the harmonics are wanted.
>>> That's an engineer's answer. Musicians know that pianos can distort,
>>> acoustically, with never a mic, amp or speaker in sight.
>> Have the tech fiddle with the damping until it stops.
>> --scott
>
> You can often drive a piano into distortion just by how hard you hit the
> keys.
>

Until you break a string. Then you get in trouble.

--
Les Cargill

[Scott Dorsey]

Les Cargill > wrote:
>Until you break a string. Then you get in trouble.

Then you just transpose the piece up or down to a key where you don't need
that note any more.

Paderewski could do it anyway.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[KGT]

On Oct 11, 10:45*am, (Scott Dorsey) wrote:
> John O'Flaherty > wrote:
>
> > I did some tests on speakers I use for a digital piano, and find that
> >they have ~10% distortion @ 90 dB spl. I would like to get some better
> >speakers, maybe studio monitors. I find a lot of these with claims of
> >"low distortion", but none so far with actual specifications. The few
> >units that have a distortion spec are powered units, with distortion
> >of a fraction of a percent, which probably applies to the amplifier
> >only. Do any speaker manufacturers provide distortion figures for
> >their speakers, or is there a review source where someone else has
> >tested them?
>
> There are no speakers with low distortion. *In general, the things people
> do to increase directivity (which increases efficiency) will increase
> distortion. * In general, distortion at low frequencies is higher than
> distortion at high frequencies. *In general, nobody will give you a distortion
> spec on a loudspeaker because there is no standard way of measuring it.
>
> Seeing as how there are no low distortion speakers out there, your goal often
> becomes a job of juggling different kinds of distortion and finding the least
> offensive kind.
>
I'm surprized no one said this yet But IMHO you need a very different
speaker/amp for digital piano reproduction.
I suggest you google Keyboard stage amplifiers or powered speakers.
All the live
players I know use full range systems with tons of headroom for the
levels desired. Something like qsc K10/12 or
Baretta combo units. but for $1k you could not get 2 so maybe look for
2 used EV JBL Mackie etc

[Peter A. Stoll[_2_]]

(hank alrich) wrote in
:

> geoff > wrote:
>
>> Laurence Payne wrote:
>> > On Mon, 12 Oct 2009 10:21:14 +1300, "geoff"
>> > > wrote:
>> >
>> >>> That's an engineer's answer. Musicians know that pianos can
>> >>> distort, acoustically, with never a mic, amp or speaker in sight.
<snip>
> Well said. I have a truly wonderful acoustic guitar, made for me by
> the late Lance McCollum. I can get really clean out of it, or I can
> drive it into distortion just by how I attack the strings.
>
> Same for the 1921 Chickering grand here, and I'm no real piano player.

I'm puzzled by the "piano distortion" comments. I'm a pretty serious
amateur pianist and somewhat less serious amateur sound guy. I also
shopped a year or so ago for an electronic piano for my daughter,
auditioning the locally available models in roughly the $2,000 to $7,000
range.

To my ears, it seems that the sound of a piano note changes gradually as
you hit it harder and harder (I assume this mostly means changes in the
relative weights in the overtone series technically, but I'd describe the
acoustic affect to some degree as getting gradually brighter and
harsher). I think the degree and rate of this probably vary with the
design of different piano models. To my ears and hands, one flaw of the
best Roland keyboard I played was that this effect came on too swiftly--
much more rapid onset with increased key pressure than on any real piano
I have played (I think the samples on that one were from a Steinway D,
and I have played enough Steinways to say I don't think they got that
aspect right). For what it is worth, in the end I chose a Yamaha
middling model--using decent headphones I could actually forget I was
playing an electronic imitation and concentrate on making music, though
they sound through the speakers was not even close. My home piano is a
1908 Steinway O, and I definitely play the very loudest bits without any
restraint to hold back from distortion.

I'd also comment that I believe that real piano performers hit the thing
about as hard as humanly possible for the loudest bits in loud pieces.
I've never heard of them holding back to avoid "distortion".

Long comment-short question. What is it that you think of as distortion
in a piano? (I mean the sound the piano makes, not things done to the
sound by electronics, rooms, or "preparation"). I'm genuinely curious--
not spoiling for a fight.

[John O'Flaherty]

On 11 Oct 2009 10:45:08 -0400, (Scott Dorsey) wrote:

>John O'Flaherty > wrote:
>> I did some tests on speakers I use for a digital piano, and find that
>>they have ~10% distortion @ 90 dB spl. I would like to get some better
>>speakers, maybe studio monitors. I find a lot of these with claims of
>>"low distortion", but none so far with actual specifications. The few
>>units that have a distortion spec are powered units, with distortion
>>of a fraction of a percent, which probably applies to the amplifier
>>only. Do any speaker manufacturers provide distortion figures for
>>their speakers, or is there a review source where someone else has
>>tested them?
>
>There are no speakers with low distortion. In general, the things people
>do to increase directivity (which increases efficiency) will increase
>distortion. In general, distortion at low frequencies is higher than
>distortion at high frequencies. In general, nobody will give you a distortion
>spec on a loudspeaker because there is no standard way of measuring it.

It seems like they could come up with something standard pretty
easily. So many dB SPL, a particular distance, pure tones at a few
selected frequencies.

>Seeing as how there are no low distortion speakers out there, your goal often
>becomes a job of juggling different kinds of distortion and finding the least
>offensive kind.
>
>What don't you like about the sound of the speakers you have?

As you noted elsewhere, they're godawful. The sound is clearer through
inexpensive headphones, but I still want speakers. It's also a honky
sound. Some of the problem is likely room resonance, but I'm hoping
some new speakers will at least improve it. Anyhow, given that I've
decided to get new speakers, I hoped there might be some with
published distortion specs, but if there aren't any, that settles
that.
--
John

[GregS[_3_]]

In article >, John O'Flaherty > wrote:
>On 11 Oct 2009 10:45:08 -0400, (Scott Dorsey) wrote:
>
>>John O'Flaherty > wrote:
>>> I did some tests on speakers I use for a digital piano, and find that
>>>they have ~10% distortion @ 90 dB spl. I would like to get some better
>>>speakers, maybe studio monitors. I find a lot of these with claims of
>>>"low distortion", but none so far with actual specifications. The few
>>>units that have a distortion spec are powered units, with distortion
>>>of a fraction of a percent, which probably applies to the amplifier
>>>only. Do any speaker manufacturers provide distortion figures for
>>>their speakers, or is there a review source where someone else has
>>>tested them?
>>
>>There are no speakers with low distortion. In general, the things people
>>do to increase directivity (which increases efficiency) will increase
>>distortion. In general, distortion at low frequencies is higher than
>>distortion at high frequencies. In general, nobody will give you a distortion
>>spec on a loudspeaker because there is no standard way of measuring it.
>
>It seems like they could come up with something standard pretty
>easily. So many dB SPL, a particular distance, pure tones at a few
>selected frequencies.
>

Drivers usually have increasing distortion with increasing drive voltage.

Paul Klipsh used to show distortion with and without the horn
attached to the driver for a small 4 inch driver. The horn permitted the drive to be reduced
by 1/3. I'm am going to guess that ribbons will also have lower distortions than their
conterparts. Distortion is also dependant on frequency.

greg


>>Seeing as how there are no low distortion speakers out there, your goal often
>>becomes a job of juggling different kinds of distortion and finding the least
>>offensive kind.
>>
>>What don't you like about the sound of the speakers you have?
>
>As you noted elsewhere, they're godawful. The sound is clearer through
>inexpensive headphones, but I still want speakers. It's also a honky
>sound. Some of the problem is likely room resonance, but I'm hoping
>some new speakers will at least improve it. Anyhow, given that I've
>decided to get new speakers, I hoped there might be some with
>published distortion specs, but if there aren't any, that settles
>that.

[Laurence Payne[_2_]]

On Mon, 12 Oct 2009 10:59:53 -0500, "Peter A. Stoll"
> wrote:

>Long comment-short question. What is it that you think of as distortion
>in a piano? (I mean the sound the piano makes, not things done to the
>sound by electronics, rooms, or "preparation"). I'm genuinely curious--
>not spoiling for a fight.

Squeaks, rattles and buzzes. Distorted overtones due to cost-cutting
by making the bass strings looser and thicker rather than longer.
Distorted sound due to trying to get more volume out of a small/cheap
piano than it is capable of.

[John O'Flaherty]

On Mon, 12 Oct 2009 03:04:15 +0200, Sebastian Z u e n d o r f
> wrote:

(Scott Dorsey) wrote:
>
>>You might consider the powered Mackies, for instance.
>
>The older SRM-series was about ok - the new ones are godawful, though.

Someone else thought the Mackie HR 824s were good. Why do you say
they're godawful? Just the sound, or some other aspect?
--
John

[Sebastian Z u e n d o r f]

John O'Flaherty > wrote:

>>The older SRM-series was about ok - the new ones are godawful, though.
>
>Someone else thought the Mackie HR 824s were good. Why do you say
>they're godawful? Just the sound, or some other aspect?

I was talking about the SRM 450 MKI vs. MKII PA-speakers. The old ones
were ok, but I'd never buy the MKIIs.
Studio monitors: Different thing. I found the 824s ok when I listened
to them in another studio and for a short time only.
Best advice is to go to a shop to check them out...

Sebastian


--
F: Was ist ein Mathematiker?
A: Ein Gerät das Kaffee in Behauptungen umwandelt.

Die Partyband vom Niederrhein: http://www.stimmtso.net

[Mike Clayton]

Peter A. Stoll wrote:
> I'd also comment that I believe that real piano performers hit the thing
> about as hard as humanly possible for the loudest bits in loud pieces.
> I've never heard of them holding back to avoid "distortion".

I remember back in the 1970s when I worked at the local radio station we
had a visiting pianist who was built like a blacksmith. His proud boast
was that he could play any piano louder than anybody else and left a
string of broken hammers on pianos round the country to prove it.

He's not been invited back since...

Mike

[David Gravereaux]

Scott Dorsey wrote:
> ... In general, nobody will give you a distortion
> spec on a loudspeaker because there is no standard way of measuring it.

Not fully true. See section 24 of IEC-606268-5. Here's a small sample
of what it says:

"
The harmonic distortion of the second order shall be determined by the
formula:
24.2.2.6
p2 f
d2 = ------ × 100 %
in %: pt
⎛ d2 ⎞
Ld2 = 20 lg ⎜-----⎟
in dB: âŽ� 100 âŽ*

The harmonic distortion of the third order shall be determined by the
formula:
p3 f
d3 = ------ × 100 %
in %: pt
⎛ d3 ⎞
Ld3 = 20 lg ⎜-----⎟
in dB : âŽ� 100 âŽ*

24.2.2.7 The results of the measurement shall be presented graphically
as a function of the fundamental frequency. The distortion values shall
be expressed in dB when a gliding tone method is used. When applying a
step-by-step method the expression as a percentage shall be used.
"
--



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[Scott Dorsey]

John O'Flaherty > wrote:
>On 11 Oct 2009 10:45:08 -0400, (Scott Dorsey) wrote:
>
>>There are no speakers with low distortion. In general, the things people
>>do to increase directivity (which increases efficiency) will increase
>>distortion. In general, distortion at low frequencies is higher than
>>distortion at high frequencies. In general, nobody will give you a distortion
>>spec on a loudspeaker because there is no standard way of measuring it.
>
>It seems like they could come up with something standard pretty
>easily. So many dB SPL, a particular distance, pure tones at a few
>selected frequencies.

Which frequencies, which level? Standards committees consist of
representatives from manufacturers, all of whom want a standard that makes
their product look better than everyone else's.

There is kind of an ISO standard for speaker distortion, but it's not really
completely specified, and nobody really uses the spec anyway.

>>Seeing as how there are no low distortion speakers out there, your goal often
>>becomes a job of juggling different kinds of distortion and finding the least
>>offensive kind.
>>
>>What don't you like about the sound of the speakers you have?
>
>As you noted elsewhere, they're godawful. The sound is clearer through
>inexpensive headphones, but I still want speakers. It's also a honky
>sound. Some of the problem is likely room resonance, but I'm hoping
>some new speakers will at least improve it. Anyhow, given that I've
>decided to get new speakers, I hoped there might be some with
>published distortion specs, but if there aren't any, that settles
>that.

Just about anything around will give you some improvement over what you
have. Go out and audition some speakers and see which ones you like the
sound of. I personally like the Radian coaxials for that sort of
application, but they may be too big or too small for you or they may not
sound the way you want.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

GregS > wrote:
>
>Drivers usually have increasing distortion with increasing drive voltage.

Kind of. Usually speakers have fairly high distortion at low levels because
there is a dead band; it takes a certain amount of pressure to get the voice
coil moving. Then at higher levels the distortion drops, and then when the
voice coil starts getting close to the end of the range, the distortion starts
going up again.

>Paul Klipsh used to show distortion with and without the horn
>attached to the driver for a small 4 inch driver. The horn permitted the drive to be reduced
>by 1/3.

Yes, the problem with this is that this is only effective above the lowest
corner frequency of the horn, which is set by the size of the horn. If you
want directionality at low frequencies, you need an enormous horn.

What Mr. Klipsch didn't tell you is that for a midrange or treble horn, you
require levels at the horn entrance that require a compression driver, and
and the the compression driver itself has inherently higher distortion
because of the nonlinearity when air gets compressed a lot. There is a
really great paper by Vanderkooy in the past few years on distortion modelling
using fluid dynamics models of compression drivers and horns.

Klipsch was obsessed with the notion of efficiency. Back in the 1940s, this
was a very wise philosophy because so much of the distortion in the system
at high levels came from the amplifier, and amplifier power was expensive.
In the 1970s, Crown changed everything and Klipsch never seemed to understand
that the world around him had changed.

>I'm am going to guess that ribbons will also have lower distortions than their
>conterparts. Distortion is also dependant on frequency.

Yes, this is all generally true.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[cjt]

Mark wrote:
> On Oct 14, 12:36 pm, (Adrian
> Tuddenham) wrote:
>> Scott Dorsey > wrote:
>>> Klipsch was obsessed with the notion of efficiency. Back in the 1940s, this
>>> was a very wise philosophy because so much of the distortion in the system
>>> at high levels came from the amplifier, and amplifier power was expensive.
>>> In the 1970s, Crown changed everything and Klipsch never seemed to understand
>>> that the world around him had changed.
>> There is still a niche market because battery-powered P.A. equipment
>> needs very efficient speakers. I use a pair of portable bass speakers
>> based in Klipsch's design and they can easily fill a 200-seat arena with
>> about 30 watts. (You do need to find or arrange corners to put them
>> in).
>>
>> --
>> ~ Adrian Tuddenham ~
>> (Remove the ".invalid"s and add ".co.uk" to reply)www.poppyrecords.co.uk
>
> My rule of thumb for a normal (not high efficency) system has been 1
> Watt per person...
>
> Mark
>
Well, it's just me and the wife ...

[Adrian Tuddenham[_2_]]

Scott Dorsey > wrote:


> Klipsch was obsessed with the notion of efficiency. Back in the 1940s, this
> was a very wise philosophy because so much of the distortion in the system
> at high levels came from the amplifier, and amplifier power was expensive.
> In the 1970s, Crown changed everything and Klipsch never seemed to understand
> that the world around him had changed.

There is still a niche market because battery-powered P.A. equipment
needs very efficient speakers. I use a pair of portable bass speakers
based in Klipsch's design and they can easily fill a 200-seat arena with
about 30 watts. (You do need to find or arrange corners to put them
in).


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Mark]

On Oct 14, 12:36*pm, (Adrian
Tuddenham) wrote:
> Scott Dorsey > wrote:
> > Klipsch was obsessed with the notion of efficiency. *Back in the 1940s, this
> > was a very wise philosophy because so much of the distortion in the system
> > at high levels came from the amplifier, and amplifier power was expensive.
> > In the 1970s, Crown changed everything and Klipsch never seemed to understand
> > that the world around him had changed.
>
> There is still a niche market because battery-powered P.A. equipment
> needs very efficient speakers. *I use a pair of portable bass speakers
> based in Klipsch's design and they can easily fill a 200-seat arena with
> about 30 watts. *(You do need to find or arrange corners to put them
> in).
>
> --
> ~ Adrian Tuddenham ~
> (Remove the ".invalid"s and add ".co.uk" to reply)www.poppyrecords.co.uk

My rule of thumb for a normal (not high efficency) system has been 1
Watt per person...

Mark

[Geoff]

cjt wrote:
> Mark wrote:

>>
>> My rule of thumb for a normal (not high efficency) system has been 1
>> Watt per person...
>>
>> Mark
>>
> Well, it's just me and the wife ...

So will that be two watts total, or two watts 'per channel'. RMS or Music
Power ?

See, nothing is ever simple.....


geoff

[Arny Krueger]

"Les Cargill" > wrote in message

> hank alrich wrote:
>> Scott Dorsey > wrote:
>>
>>> Laurence Payne > wrote:
>>>> On Sat, 10 Oct 2009 17:04:57 GMT,
>>>> (Don Pearce) wrote:
>>>>
>>>>>> Bonus question: How much distortion is there in a
>>>>>> real piano?
>>>>> A piano is a source, not a reproducer. It is by
>>>>> definition distortion-free. All the harmonics are
>>>>> wanted.
>>>> That's an engineer's answer. Musicians know that
>>>> pianos can distort, acoustically, with never a mic,
>>>> amp or speaker in sight.
>>> Have the tech fiddle with the damping until it stops.
>>> --scott
>>
>> You can often drive a piano into distortion just by how
>> hard you hit the keys.
>>
>
> Until you break a string. Then you get in trouble.

IME you are more likely to break some of the wooden parts of the action. Or,
so I am told by techs who work on ours.

[Arny Krueger]

"John O'Flaherty" > wrote in message

> Hello all,
>
> I did some tests on speakers I use for a digital piano,
> and find that they have ~10% distortion @ 90 dB spl. I
> would like to get some better speakers, maybe studio
> monitors. I find a lot of these with claims of "low
> distortion", but none so far with actual specifications.
> The few units that have a distortion spec are powered
> units, with distortion of a fraction of a percent, which
> probably applies to the amplifier only. Do any speaker
> manufacturers provide distortion figures for their
> speakers, or is there a review source where someone else
> has tested them?

Some manufacturers such as EV and JBL provide distortion specs for some of
their speakers.

Typically, nonlinear distortion is fairly low (under 1% THD) at lower
levels and higher frequencies. 10% THD would only be acceptable in the bass
range (< 100 Hz), where it might be surprisingly non-disruptive.