[AbsenceStudios]

I've seen a few articles on the net about people measuring the frequency
response of their control rooms.

How does one go about this? Is it a worthwile exercise, or an exercise in
futility?

I ask because I want to acoustically treat my control room, and I want to
see the results of doing so.

One more question: is the http://www.acoustics101.com/ a good source for
beginning to learn about the science of acoustic treatment?

[cedricl]

On Mar 27, 9:54*pm, "AbsenceStudios" wrote:
I've seen a few articles on the net about people measuring the frequency
response of their control rooms.

How does one go about this? *Is it a worthwile exercise, or an exercise in
futility?

I ask because I want to acoustically treat my control room, and I want to
see the results of doing so.

One more question: is thehttp://www.acoustics101.com/a good source for
beginning to learn about the science of acoustic treatment?

You get a pink noise generator and run pink noise through your
speakers. You use a computer with an audio analysis application like
"Smaart Live" and run the output of an analysis microphone like a
Berringer 8000 through your computer interface to the application to
get a "picture" of your room's frequency response. It's useful in that
you can EQ your speakers to match the room to get the flattest
response or use room treatment to obtain the flattest response. This
EQ would then be your "set and forget" reference for all your mixes.
EQ to taste but use a separate EQ to keep the "flat" response you got
from the analysis.

[Eeyore]

AbsenceStudios wrote:

I've seen a few articles on the net about people measuring the frequency
response of their control rooms.

At what listening location ?

Truth is, the human ear is VERY good at adapting to room acoustics.

As long as the speaker is reasonably 'truthful' there's not that much need to
worry since your brain will make most of the required corrections
automatically. Exceptions for shockingly live or reverberant rooms obviously.


Graham

[Eeyore]

cedricl wrote:

You get a pink noise generator and run pink noise through your
speakers. You use a computer with an audio analysis application like
"Smaart Live" and run the output of an analysis microphone like a
Berringer 8000 through your computer interface to the application to
get a "picture" of your room's frequency response.

At the measuring mic's location ONLY.

Graham

[David Gravereaux]

AbsenceStudios wrote:
How does one go about this? Is it a worthwile exercise, or an exercise in
futility?

Personally, I consider 3 aspects: flutter echo, LF room modes and
general deadness.

Flutter echo is caused parallel reflective surfaces and should be the
first problem addressed. Just clap your hands and listen for non even
decay (quick boing-boing like sounds) and identify where it comes from.
The quick fix is to hang some Persian rugs on the side walls or put
one on the floor if it isn't carpeted.

To find LF room modes, place a subwoofer in your listening spot and
drive it with a sine wave generator. Pick a start frequency like 28Hz
and walk around the room listening for sound buildup or cancelations.
Move the frequency up and walk around some more, repeat up to about 130Hz.

There are tricks to fixing bass response, but can usually take a great
effort beyond simple cylindrical bass traps placed in the buildup spots.
I had great results with two helmholtz slat resonators placed in the
back wall parallel opposite from the main speakers tuned to exactly the
room depth measurement which was a short 5 feet, which gave a half wave
@ 110Hz. I got great compliments on how well the NS-10s sounded..
Haha.. It was the room, not the speakers!

A dead room is an uncomfortable room. If you follow the LEDE principle
placing deadening material in the front half and diffuse/spectoral
material in the back and romove any slap/flutter coming from the sides,
you'll be in good shape.

Futile work? hell no. Either it sounds great or it sucks.

[Arny Krueger]

"Soundhaspriority" wrote in message

"AbsenceStudios" wrote in
message
. ..
I've seen a few articles on the net about people
measuring the frequency response of their control rooms.

How does one go about this? Is it a worthwile exercise,
or an exercise in futility?

I ask because I want to acoustically treat my control
room, and I want to see the results of doing so.

One more question: is the http://www.acoustics101.com/ a
good source for beginning to learn about the science of
acoustic treatment?

To do it on the cheap: Get a Radio Shack SPL meter, and a
test CD. The Stereophile Test CD2,
http://www.stereophile.com/features/338/index14.html ,
can be found on eBay. Tracks 16,17, and 18 are most
useful. The CD employs warble tones.

There are also a number of good test CDs and downloads that come out of the
car sound and home theatre world.

http://www.testaudio.com/testaudio/products.asp

http://www.hometheaterhifi.com/down/

http://www.rainfall.com/cdroms/audiotestII.htm

www.audioc.com/pdf1/subtestcd.pdf -

This is important.
Constant tones, provided, for example, by a test
oscillator, tend to provoke room resonances, and confuse
the user with narrow band modes that are not
realistically correctable. Warble tones average the
response over 1/3 octave, providing a smoothed version of
room response that shows the trend.

So far so good.

In the bass range, you will be able to see and work on
correction of room modes.

Most effective means involve acoustics treatments like bass traps.

http://www.realtraps.com/

In the mids and treble, you'll see speaker anomalies
combined with room absorption. Correction is not
straightforward, because the ear perceives the first
wavefront differently from reflected sound. Equalizing a
room to "flat" is usually very disappointing.

http://www.hometheaterhifi.com/volum...es-6-2002.html

http://www.modernhometheater.com/how...304/index.html

And absorptive material can be overused. The most
sophisticated rooms combine both diffusion and
absorption.

They also include some reflection. The three basics are diffusion,
absorbtion, and reflection. We usually have too much reflection, but there
is such a thing as too little reflection.

According to one concept, the area nearest
the speakers should be absorptive, as should all ray
traceable first reflections. The remaining area is
treated with diffusive, rather than reflective, surfaces.

Without reflections, its hard to tell where things are.

The Radio Shack instrument does not have a regulated
power supply.

Not a problem at all. The real problem with the RS SPL meter is that its
microphone is very primitive and the electronics are only a little bit
better. Better SPL meters can be had for not a lot more money. But, its
more to the point to get a flat measurement-type microphone and use it in
conjuction with software running on a PC.

Besides an inaccurate mike and lack of
calibration, measurements are not very repeatable. But if
you use it as something to sniff anomalies, it can help
you get going in the right direction.

Good point. With some difficulty, you can do acoustic measurements that are
repeatable within less than a dB. But the hundreth-dB type measurements we
can do on electronic equipment are mission impossible if for no reason other
than that air currents due to convection in the room will cause measurable
changes.

A 1 dB error in response over several octaves can have a strong audible
effect. Acoustic measurements also tend to vary as you move around in the
room, even with warble tones, pink noise, or other test signals. How do you
characterize something that changes so much as you move small distances?

[Don Pearce]

On Thu, 27 Mar 2008 21:54:32 -0700, "AbsenceStudios"
wrote:

I've seen a few articles on the net about people measuring the frequency
response of their control rooms.

How does one go about this? Is it a worthwile exercise, or an exercise in
futility?

I ask because I want to acoustically treat my control room, and I want to
see the results of doing so.

One more question: is the http://www.acoustics101.com/ a good source for
beginning to learn about the science of acoustic treatment?


Unfortunately a room doesn't have a frequency response - at least not
until you have got it right.

There is a different frequency response between any two points in a
room - and the differences aren't trivial, they will differ by tens of
dBs.

To get your room right you need to do two things. First sort out the
reverberation time, which you do with absorbent materials. There are
plenty of sources which will tell you what reverb time you need at
various frequencies, depending on music type, room size etc.

Also, you need to prevent modes (the cause of the huge variations). To
do this you need to make sure that you don't have flat surfaces facing
each other - clutter is your friend. You may find yourself juggling
both of these before you are happy.

When you have a specific problem at a specific frequency consider a
trap. It can succeed where all else fails.

With all of this done you will have a room in which frequency response
is a meaningful concept. Oh, and it will be essentially flat, because
what a good room does is leave the response of the system unchanged.

d

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

[William Sommerwerck]

You aren't the least bit interested of the response of the room, but the
response of the speaker within the room.

As for using warble tones... They hide the very effects you're looking for.

[Arny Krueger]

"William Sommerwerck" wrote in
message

You aren't the least bit interested of the response of
the room, but the response of the speaker within the room.

Agreed.

As for using warble tones... They hide the very effects
you're looking for.

Depends on how wide the warbling is.

[Mike Rivers]

On Mar 28, 1:15 am, "Soundhaspriority" wrote:

The Radio Shack instrument does not have a regulated power supply. Besides
an inaccurate mike and lack of calibration, measurements are not very
repeatable.

Bob, you start out so good, and then you throw in a piece of crap like
this. A battery is about as good a regulated power supply as you can
get, until it dies (which will be obvious since the meter has a
Battery Test function). And while it's not perfectly flat, it's pretty
darn good, better than most rooms. Someplace around here I have a
correction table for it, and it's not more than about 3 dB anywhere in
the audible range.

The most important thing about acoustic measurements is knowing how
to interpret them. That's not simple.

[Scott Dorsey]

AbsenceStudios wrote:
I've seen a few articles on the net about people measuring the frequency
response of their control rooms.

There isn't just one. There are millions of them, in every room. Move an
inch, and the room response changes.

How does one go about this? Is it a worthwile exercise, or an exercise in
futility?

It's worth doing simple room sweeps to get a sense of where the problems
with the room are and what is generally going on.

I ask because I want to acoustically treat my control room, and I want to
see the results of doing so.

How can you acoustically treat your control room if you don't know what
the problems are and where they are?

One more question: is the http://www.acoustics101.com/ a good source for
beginning to learn about the science of acoustic treatment?

I have no idea, but I suggest buying the F. Alton Everest book on small
studio acoustics (or getting it from the library) and reading it carefully.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Ethan Winer]

I've seen a few articles on the net about people measuring the frequency
response of their control rooms. How does one go about this?

See this:

http://www.realtraps.com/art_etf.htm

Is it a worthwile exercise, or an exercise in futility?

The main reason to measure a mix room is to see how bad it truly is, and to
assess the improvement after it's been treated. You do not usually need to
measure a room to know how to treat it, because the strategy is the more or
less the same for all rooms.

I ask because I want to acoustically treat my control room, and I want to
see the results of doing so.

Yes, that's a good reason.

One more question: is the http://www.acoustics101.com/ a good source for
beginning to learn about the science of acoustic treatment?

I'm biased, but I think this is much better and certainly more coherent
written:

http://www.ethanwiner.com/acoustics.html

Much more he

http://www.realtraps.com/articles.htm

--Ethan

[AbsenceStudios]

Scott,

F. Alton Everest has written quite a few books revolving around building
studios and using acoustics.

I have "Critical Listening For Audio Professionals" and "Master Handbook Of
Acoustics." I have started to get into "Critical Listening..."

I'm looking for a primer to get me started. Are you talking about his book
"Acoustic Techniques for Home and Studio?"

Thanks,

David

=========================

"Scott Dorsey" wrote in message
...
AbsenceStudios wrote:
I've seen a few articles on the net about people measuring the frequency
response of their control rooms.

There isn't just one. There are millions of them, in every room. Move an
inch, and the room response changes.

How does one go about this? Is it a worthwile exercise, or an exercise in
futility?

It's worth doing simple room sweeps to get a sense of where the problems
with the room are and what is generally going on.

I ask because I want to acoustically treat my control room, and I want to
see the results of doing so.

How can you acoustically treat your control room if you don't know what
the problems are and where they are?

One more question: is the http://www.acoustics101.com/ a good source for
beginning to learn about the science of acoustic treatment?

I have no idea, but I suggest buying the F. Alton Everest book on small
studio acoustics (or getting it from the library) and reading it
carefully.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[AbsenceStudios]

Ethan,

That is a good amount of material!

Thank you for your help,

David

=========================

"Ethan Winer" ethanw at ethanwiner dot com wrote in message
...
I've seen a few articles on the net about people measuring the frequency
response of their control rooms. How does one go about this?

See this:

http://www.realtraps.com/art_etf.htm

Is it a worthwile exercise, or an exercise in futility?

The main reason to measure a mix room is to see how bad it truly is, and
to assess the improvement after it's been treated. You do not usually need
to measure a room to know how to treat it, because the strategy is the
more or less the same for all rooms.

I ask because I want to acoustically treat my control room, and I want to
see the results of doing so.

Yes, that's a good reason.

One more question: is the http://www.acoustics101.com/ a good source for
beginning to learn about the science of acoustic treatment?

I'm biased, but I think this is much better and certainly more coherent
written:

http://www.ethanwiner.com/acoustics.html

Much more he

http://www.realtraps.com/articles.htm

--Ethan

[AbsenceStudios]

Graham,

I have a set of JBL LSR4328's. I am reasonably happy with my listening
position, which has been setup to be an equilateral triangle--left monitor,
right monitor, and me.

What I want is a room that I can count on to be more reliable everywhere I
am standing/sitting in it.

I forgot to mention that I'd also like to be able to do some tracking in the
same room (mostly quiet acoustic instruments).

I realize that I could just learn my monitors as they are and get used to
mixing with them, but I am looking at this profession as a lifelong career,
and with that said, from a business standpoint. I would like clients to be
able to hear the results of their playing and my tracking in a suitable
environment. I would also like the acoustics to be more uniform, so that in
the future, when my studio is no longer in my house, I won't have as hard of
a time relearning the monitors I've gathered in a new envrionment.

Regards,

David

=========================

"Eeyore" wrote in message
...


AbsenceStudios wrote:

I've seen a few articles on the net about people measuring the frequency
response of their control rooms.

At what listening location ?

Truth is, the human ear is VERY good at adapting to room acoustics.

As long as the speaker is reasonably 'truthful' there's not that much need
to
worry since your brain will make most of the required corrections
automatically. Exceptions for shockingly live or reverberant rooms
obviously.


Graham

[AbsenceStudios]

Arny,

Thank you for the resources.

David

=========================

"Arny Krueger" wrote in message
. ..
"Soundhaspriority" wrote in message

"AbsenceStudios" wrote in
message
. ..
I've seen a few articles on the net about people
measuring the frequency response of their control rooms.

How does one go about this? Is it a worthwile exercise,
or an exercise in futility?

I ask because I want to acoustically treat my control
room, and I want to see the results of doing so.

One more question: is the http://www.acoustics101.com/ a
good source for beginning to learn about the science of
acoustic treatment?

To do it on the cheap: Get a Radio Shack SPL meter, and a
test CD. The Stereophile Test CD2,
http://www.stereophile.com/features/338/index14.html ,
can be found on eBay. Tracks 16,17, and 18 are most
useful. The CD employs warble tones.

There are also a number of good test CDs and downloads that come out of
the car sound and home theatre world.

http://www.testaudio.com/testaudio/products.asp

http://www.hometheaterhifi.com/down/

http://www.rainfall.com/cdroms/audiotestII.htm

www.audioc.com/pdf1/subtestcd.pdf -

This is important.
Constant tones, provided, for example, by a test
oscillator, tend to provoke room resonances, and confuse
the user with narrow band modes that are not
realistically correctable. Warble tones average the
response over 1/3 octave, providing a smoothed version of
room response that shows the trend.

So far so good.

In the bass range, you will be able to see and work on
correction of room modes.

Most effective means involve acoustics treatments like bass traps.

http://www.realtraps.com/

In the mids and treble, you'll see speaker anomalies
combined with room absorption. Correction is not
straightforward, because the ear perceives the first
wavefront differently from reflected sound. Equalizing a
room to "flat" is usually very disappointing.

http://www.hometheaterhifi.com/volum...es-6-2002.html

http://www.modernhometheater.com/how...304/index.html

And absorptive material can be overused. The most
sophisticated rooms combine both diffusion and
absorption.

They also include some reflection. The three basics are diffusion,
absorbtion, and reflection. We usually have too much reflection, but
there is such a thing as too little reflection.

According to one concept, the area nearest
the speakers should be absorptive, as should all ray
traceable first reflections. The remaining area is
treated with diffusive, rather than reflective, surfaces.

Without reflections, its hard to tell where things are.

The Radio Shack instrument does not have a regulated
power supply.

Not a problem at all. The real problem with the RS SPL meter is that its
microphone is very primitive and the electronics are only a little bit
better. Better SPL meters can be had for not a lot more money. But, its
more to the point to get a flat measurement-type microphone and use it in
conjuction with software running on a PC.

Besides an inaccurate mike and lack of
calibration, measurements are not very repeatable. But if
you use it as something to sniff anomalies, it can help
you get going in the right direction.

Good point. With some difficulty, you can do acoustic measurements that
are repeatable within less than a dB. But the hundreth-dB type
measurements we can do on electronic equipment are mission impossible if
for no reason other than that air currents due to convection in the room
will cause measurable changes.

A 1 dB error in response over several octaves can have a strong audible
effect. Acoustic measurements also tend to vary as you move around in the
room, even with warble tones, pink noise, or other test signals. How do
you characterize something that changes so much as you move small
distances?

[AbsenceStudios]

Two people have mentioned measurement mics and software.

Are there any decent measurement mics in the $1000 range?

Are there software options I should consider beyond SMAART and ETF?

[cedricl]

On Mar 27, 10:29*pm, Eeyore
wrote:
cedricl wrote:
You get a pink noise generator and run pink noise through your
speakers. You use a computer with an audio analysis application like
"Smaart Live" and run the output of an analysis microphone like a
Berringer 8000 through your computer interface to the application to
get a "picture" of your room's frequency response.

At the measuring mic's location ONLY.

Graham

Well, you generally only mix from one position so if you set the mic
up at your heads' position when you mix it will give a reasonable
representation of what you're hearing when you mix.

[cedricl]

On Mar 28, 6:12*pm, "AbsenceStudios" wrote:
Two people have mentioned measurement mics and software.

Are there any decent measurement mics in the $1000 range?

Are there software options I should consider beyond SMAART and ETF?

Spectre looks pretty good. A co-worker spent lots of money on a well
known big name reference mic and then when guys started getting the
Berringer he compared the two using Smaart Live and said, "he wished
he'd saved his money". For $80 you can buy two and have some cheap
room mics to use for recording when not in use for analysis. A great
computer interface is the Sound Devices USB Pre for about $500. I
forget what Spectre cost but that combination of application, mics and
computer interface should be less than $1000.

[Scott Dorsey]

AbsenceStudios wrote:
Two people have mentioned measurement mics and software.

Are there any decent measurement mics in the $1000 range?

Are there software options I should consider beyond SMAART and ETF?

There are, but you don't need any more than just a signal generator
and your ear.

Set the generator for 60 Hz. Stick a finger in one ear. Walk around
the room. Find the peaks and nulls. Now try again a third octave up.
You'll hear where all the problems are.

If you are happy with the sound at the mix position, and you move out
of the sweet spot, what happens? Does the high end change, or does
the low end change completely? By doing simple tone tests and listening
you'll know what changes, you'll know where the room problems are, and
you'll be on your way toward dealing with them.

If you want a somewhat more sophisticated method, get the Radio Shack
analogue sound level meter for $40 or so.

A calibrated measurement mike is a great thing, but you don't need one
yet. First you need to get a rough idea of what is wrong with the
room.
--scott

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

[Scott Dorsey]

cedricl wrote:
On Mar 27, 10:29=A0pm, Eeyore
wrote:
cedricl wrote:
You get a pink noise generator and run pink noise through your
speakers. You use a computer with an audio analysis application like
"Smaart Live" and run the output of an analysis microphone like a
Berringer 8000 through your computer interface to the application to
get a "picture" of your room's frequency response.

At the measuring mic's location ONLY.

Graham

Well, you generally only mix from one position so if you set the mic
up at your heads' position when you mix it will give a reasonable
representation of what you're hearing when you mix.

Unfortunately, I sometimes move my head around when I mix. I don't keep
it clamped in a vise so it's unable to move six inches away.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Chris Hornbeck]

On Fri, 28 Mar 2008 18:01:24 -0700, "AbsenceStudios"
wrote:

What I want is a room that I can count on to be more reliable everywhere I
am standing/sitting in it.

Which, as you know, is an impossibly tough requirement, if
defined strictly enough. Only a completely dead (or outdoors)
environment can be the same everywhere. But a room
without terrible resonances can have a similar
"character" most everywhere away from the walls. And
even this (the lack of terrible resonances) is tough and
requires study and effort.


The smaller the room, the more the effort required, so
bigger is really better, with exceptions outside of most
of our price ranges. A fourteen foot ceiling is a gift
from your god, but few are chosen.


I forgot to mention that I'd also like to be able to do some tracking in the
same room (mostly quiet acoustic instruments).

You'll hopefully be reading better informed and more diverse
ideas, but my personal thought is that the main difference
of acoustics between a tracking room and a critical listening
room (both are different from "pleasurable" listening rooms,
which vary tremenduously with music styles) is adjustable
with some serious gobo'ing immediately behind the critical
listener's position.

A good room in both cases has random (an amazingly difficult
goal!) and colorless reflections, and has reflections that
begin after an *appropriate* time delay. The time delay can
only be addressed geometrically - bigger is better (longer)
and numbers under 15 milliSeconds just don't seem get to be
"too big".

(Although "too big" is certainly possible - it's just that
Who can afford it?)

The time delay is, of course, the difference between path
lengths of the direct and the reflected paths, measured
with a tape rule, and divided into 1130 ft/sec in some arcane
way. Might involve a reciprocal or something. But simple
geometry and an ability to sign large checks.

So, IMO, the main difference is in the ability to listen
"forward" to critically examine the sound of what's
possibly the same room.


I realize that I could just learn my monitors as they are and get used to
mixing with them, but I am looking at this profession as a lifelong career,
and with that said, from a business standpoint. I would like clients to be
able to hear the results of their playing and my tracking in a suitable
environment. I would also like the acoustics to be more uniform, so that in
the future, when my studio is no longer in my house, I won't have as hard of
a time relearning the monitors I've gathered in a new envrionment.

Seems to me like you've got your **** together. I may not
know everything about sound, but I do know about
(other folks'!) having their **** together. And it seems like
you got it.

All the best fortune,

Chris Hornbeck
Unsigned review of the Rubinstein Beethoven Sonatas on Amazon:
"In both CD and SACD mode on several of my players there is a faint
hiss from the original tapes captured onto this album. Very disappointing."
(some spelling corrected)

[Chris Hornbeck]

On 28 Mar 2008 21:45:14 -0400, (Scott Dorsey) wrote:

A calibrated measurement mike is a great thing, but you don't need one
yet. First you need to get a rough idea of what is wrong with the
room.

Almost nobody believes this at first go, so if you (the OP)
don't, first time 'round, don't beat yourself up too much.

Another perspective, and sometimes not posted because it's
too complicated to explain, is that "frequency response"
isn't really what's important or interesting, even IF such
a critter existed. The real world issue involves both
magnitude and time, and in three dimensions. Simplified
models are, to some big amount, just a distraction.

Ethan's pages are a solid real-world attack on things
that at some level CANNOT be simplified to the level
of a single "frequency response".

And the classic books are still classic for good reasons.
It's fun and knowable stuff, and experimentation is
well rewarded (by ear!). Can't beat it. Big fun.


All the best fortune,

Chris Hornbeck
Unsigned review of the Rubinstein Beethoven Sonatas on Amazon:
"In both CD and SACD mode on several of my players there is a faint
hiss from the original tapes captured onto this album. Very disappointing."
(some spelling corrected)

[Richard Crowley]

"Soundhaspriority" wrote ...
"Mike Rivers" wrote ...
"Soundhaspriority" wrote:
The Radio Shack instrument does not have a regulated
power supply. Besides an inaccurate mike and lack of
calibration, measurements are not very
repeatable.

Bob, you start out so good, and then you throw in a piece
of crap like this. A battery is about as good a regulated power
supply as you can get, until it dies (which will be obvious since
the meter has a Battery Test function)..

The RS digital SPL metter has only a "low battery"
indicator on the LCD display. So we are at the
(undocumented) mercy of whatever the designers
decided is "low".

In one sense a battery is a rather low-impedance source.
But OTOH, its output voltage droops over its useful
period. I wouldn't use the word "regulated" to describe
that behavior.

[snip]

Mike, I'm staring at it. Cat no. 33-2055 "Realistic Sound
Level Meter" (digital.)

The measurement is not repeatable. Repeated use over a
short interval results in a series of readings that drift down,
just like a flashlight that dims if turned on for a few minutes.
Turning it off for a period revese the effect, as the battery
depolarizes.

With a fresh battery (as recommended in the manual)?
Or with whatever happens to be installed at the moment?

Are you actually seeing the effect of battery voltage droop,
or the effect of the SPL averaging function?

It has no battery test function.

Lack of a battery test function (not to mention lack of
calibration or measured FR) reveals the Radio Shack
meter to be a mass-market consumer gadget trying to look
like a piece of serious test equipment. I'm not saying that
it has no practical use, but not in any objective way.

[Mike Rivers]

On Mar 29, 12:20 am, "Soundhaspriority" wrote:

Mike, I'm staring at it. Cat no. 33-2055 "Realistic Sound Level Meter"
(digital.)

Wrong meter. You should be looking at the analog meter Model: 33-4050

The measurement is not repeatable. Repeated use over a short interval
results in a series of readings that drift down, just like a flashlight that
dims if turned on for a few minutes. Turning it off for a period revese the
effect, as the battery depolarizes.

No acoustic measurement is repeatable unless it's in a controlled
environment. With the analog meter, you take an eyeball average of the
reading. It's too difficult to do that with the digital meter.

It has no battery test function.

Again, wrong meter.

[Mike Rivers]

On Mar 29, 7:31 am, "Richard Crowley" wrote:

The RS digital SPL metter has only a "low battery"
indicator on the LCD display. So we are at the
(undocumented) mercy of whatever the designers
decided is "low".

They probably know what they're talking about.

In one sense a battery is a rather low-impedance source.
But OTOH, its output voltage droops over its useful
period. I wouldn't use the word "regulated" to describe
that behavior.

Alkaline batteries are quite stable after an initial drop in voltage
which, assuming a competent design, will be accounted for by voltage
regulation in the circuitry that needs regulation. Short term
stability of a good battery is very good.

Lack of a battery test function (not to mention lack of
calibration or measured FR) reveals the Radio Shack
meter to be a mass-market consumer gadget

Well, what do you expect for $45? Do you think a mass market consumer
will make any more useful measurements of his room with a $800 B&K
meter? Geez, I have the Alan Parsons Sound Check 2 CD kit which has an
SPL meter with 3 dB LED steps built into the case. It's quite
informative when looking at sweeps and 1/3-octave noise on the CD.
Would I use it to proof and certify a room that I had just been paid
big bucks to treat? Nope. But it's fine for telling me where to start
working. The Radio Shack SPL meter is just an alternate display.

[Richard Crowley]

"Mike Rivers" wrote ...
"Soundhaspriority" wrote:
Mike, I'm staring at it. Cat no. 33-2055 "Realistic Sound
Level Meter" (digital.)

Wrong meter. You should be looking at the analog meter
Model: 33-4050

I continue to be pleasantly suprised that RS still sells this model
since the "digital" version is also on their shelves. I keep expecting
the analog version to disappear without notice as a result of an
arbitrary decison by some non-technical "product manager".

[William Sommerwerck]

"Mike Rivers" wrote in message
...

Well, what do you expect for $45? Do you think a mass market consumer
will make any more useful measurements of his room with a $800 B&K
meter? Geez, I have the Alan Parsons Sound Check 2 CD kit which
has an SPL meter with 3 dB LED steps built into the case. It's quite
informative when looking at sweeps and 1/3-octave noise on the CD.
Would I use it to proof and certify a room that I had just been paid
big bucks to treat? Nope. But it's fine for telling me where to start
working. The Radio Shack SPL meter is just an alternate display.

Some magazine -- I don't remember which -- reviewed all the RS sound-level
meters (including at least one discontinued model) within the last year.

It seems that the mic has gotten worse and worse with time. It suffers from
a rather severe HF rise -- it's anything but flat.

If I were designing a "cheap" SPL meter, I'd start by looking for a mic with
consistent response (assuming such are available), and then split for
another 50 cents in parts to flatten the response.

The RS meter is probably useful for relative measurements, but it's likely
nowhere nearly as good as it could be for the price.

[Arny Krueger]

"Soundhaspriority" wrote in message

"Mike Rivers" wrote in message
...
On Mar 28, 1:15 am, "Soundhaspriority"
wrote:
The Radio Shack instrument does not have a regulated
power supply. Besides
an inaccurate mike and lack of calibration,
measurements are not very repeatable.

Bob, you start out so good, and then you throw in a
piece of crap like this. A battery is about as good a
regulated power supply as you can get, until it dies
(which will be obvious since the meter has a Battery
Test function)..

[snip]

Mike, I'm staring at it. Cat no. 33-2055 "Realistic Sound
Level Meter" (digital.)

The measurement is not repeatable. Repeated use over a
short interval results in a series of readings that drift
down, just like a flashlight that dims if turned on for a
few minutes. Turning it off for a period revese the
effect, as the battery depolarizes.
It has no battery test function.

Conventional wisdom is that the RS SPL meter to buy is the analog one. It
has none of those faults, and does have a battery test function.

[Arny Krueger]

"William Sommerwerck" wrote in
message
"Mike Rivers" wrote in message
...

Well, what do you expect for $45? Do you think a mass
market consumer will make any more useful measurements
of his room with a $800 B&K meter? Geez, I have the Alan
Parsons Sound Check 2 CD kit which
has an SPL meter with 3 dB LED steps built into the
case. It's quite informative when looking at sweeps and
1/3-octave noise on the CD. Would I use it to proof and
certify a room that I had just been paid big bucks to
treat? Nope. But it's fine for telling me where to start
working. The Radio Shack SPL meter is just an alternate
display.

Some magazine -- I don't remember which -- reviewed all
the RS sound-level meters (including at least one
discontinued model) within the last year.

It seems that the mic has gotten worse and worse with
time. It suffers from a rather severe HF rise -- it's
anything but flat.

If I were designing a "cheap" SPL meter, I'd start by
looking for a mic with consistent response (assuming such
are available), and then split for another 50 cents in
parts to flatten the response.

The $2 Panasonic electret omnis need no added parts to flatten them within a
dB or less over the whole audio range. People have done mods to the RS meter
that changed over to the little Panasonics.

There are also low cost SPL meters under $125 that are alleged to perform
much better.

If you're working in a studio, using your DAW, a Berhinger ECM 8000, a mic
cord and some software seems to be the better choice. That rolls back your
costs to about the same as the RS SPL meter.

[Scott Dorsey]

William Sommerwerck wrote:
Some magazine -- I don't remember which -- reviewed all the RS sound-level
meters (including at least one discontinued model) within the last year.

It seems that the mic has gotten worse and worse with time. It suffers from
a rather severe HF rise -- it's anything but flat.

Yes, it uses one of the Horn capsules which are Panasonic and Sony clones.
They vary a lot from unit to unit.

That's still fine if what you want to do is find the peaks and dips. The
Horn capsules I have seen as much as 8 dB off from one end of the spectrum
to the other... but that's nothing compared with the size of the room
aberrations.

If I were designing a "cheap" SPL meter, I'd start by looking for a mic with
consistent response (assuming such are available), and then split for
another 50 cents in parts to flatten the response.

The RS meter is probably useful for relative measurements, but it's likely
nowhere nearly as good as it could be for the price.

True, but the next step up is the Pro-Tek which is three times the price.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Deputy Dumbya Dawg[_11_]]

"cedricl" wrote in message
...
On Mar 27, 10:29 pm, Eeyore

wrote:
cedricl wrote:
You get a pink noise generator and run pink noise through
your
speakers. You use a computer with an audio analysis
application like
"Smaart Live" and run the output of an analysis microphone
like a
Berringer 8000 through your computer interface to the
application to
get a "picture" of your room's frequency response.

At the measuring mic's location ONLY.

Graham

Well, you generally only mix from one position so if you set
the mic
up at your heads' position when you mix it will give a
reasonable
representation of what you're hearing when you mix.

Or in the other direction find the great position in your room
and make sure you keep your head there, at least when you do
your final check.

peace
dawg

[Deputy Dumbya Dawg[_11_]]

"William Sommerwerck" wrote in
message . ..
"Mike Rivers" wrote in message
...

Well, what do you expect for $45? Do you think a mass
market consumer
will make any more useful measurements of his room with a
$800 B&K
meter? Geez, I have the Alan Parsons Sound Check 2 CD kit
which
has an SPL meter with 3 dB LED steps built into the case.
It's quite
informative when looking at sweeps and 1/3-octave noise on
the CD.
Would I use it to proof and certify a room that I had just
been paid
big bucks to treat? Nope. But it's fine for telling me
where to start
working. The Radio Shack SPL meter is just an alternate
display.

Some magazine -- I don't remember which -- reviewed all the
RS sound-level
meters (including at least one discontinued model) within
the last year.

It seems that the mic has gotten worse and worse with time.
It suffers from
a rather severe HF rise -- it's anything but flat.

If I were designing a "cheap" SPL meter, I'd start by
looking for a mic with
consistent response (assuming such are available), and then
split for
another 50 cents in parts to flatten the response.

The RS meter is probably useful for relative measurements,
but it's likely
nowhere nearly as good as it could be for the price.


Getting a better tool at the beginning is like springing for a
10,999 dollar laser level for doing some general landscaping
where a string and a ten cent bubble level will get you
measured up closer than you can build / grade you project.

In the beginning you will be finding 12 db holes and peaks.
Once you get them tamed, if you are not blown away with the
improvement, then get the tools that find the tenth dB
anomalies.

peace

[AbsenceStudios]

"Scott Dorsey" wrote in message
...
The RS meter is probably useful for relative measurements, but it's likely
nowhere nearly as good as it could be for the price.

True, but the next step up is the Pro-Tek which is three times the price.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

=========================

I'm willing to pay three times the price for something that has any chance
of giving me any sort of edge on my tracking and mixing.

As I said before, I've made a career choice. My goal is to deliver
professional results and excellent customer service to clientelle.

With that being said, I'm here to learn everything I can from each and every
one of you. I read this newsgroup everyday and learn something new
everyday.

Since I lack a degree in electrical engineering, I will be teaching myself
that as well. I think many of you will be suprised at what a tenacious ****
I am.

[AbsenceStudios]

"Chris Hornbeck" wrote in message
...
On 28 Mar 2008 21:45:14 -0400, (Scott Dorsey) wrote:

A calibrated measurement mike is a great thing, but you don't need one
yet. First you need to get a rough idea of what is wrong with the
room.

Almost nobody believes this at first go, so if you (the OP)
don't, first time 'round, don't beat yourself up too much.

Another perspective, and sometimes not posted because it's
too complicated to explain, is that "frequency response"
isn't really what's important or interesting, even IF such
a critter existed. The real world issue involves both
magnitude and time, and in three dimensions. Simplified
models are, to some big amount, just a distraction.

Ethan's pages are a solid real-world attack on things
that at some level CANNOT be simplified to the level
of a single "frequency response".

And the classic books are still classic for good reasons.
It's fun and knowable stuff, and experimentation is
well rewarded (by ear!). Can't beat it. Big fun.


All the best fortune,

Chris Hornbeck
Unsigned review of the Rubinstein Beethoven Sonatas on Amazon:
"In both CD and SACD mode on several of my players there is a faint
hiss from the original tapes captured onto this album. Very
disappointing."
(some spelling corrected)

=========================

Chris,

This actually makes a remarkable amount of sense.

David

[Deputy Dumbya Dawg[_12_]]

I'm willing to pay three times the price for something that
has any chance
of giving me any sort of edge on my tracking and mixing.

As I said before, I've made a career choice. My goal is to
deliver professional results and excellent customer service
to clientelle.

With that being said, I'm here to learn everything I can
from each and every one of you. I read this newsgroup
everyday and learn something new everyday.

Since I lack a degree in electrical engineering, I will be
teaching myself that as well. I think many of you will be
suprised at what a tenacious **** I am.


Another graduate of Google university. Try doing it in steps.


peace
dawg

[AbsenceStudios]

Repliers,

Thank all of you for your help. I think I am on track now. Your collective
experience saves me time and gets me to where I need to go fast. It is much
appreciated.

David

[Mike Rivers]

On Mar 31, 5:43 pm, "AbsenceStudios" wrote:

I'm willing to pay three times the price for something that has any chance
of giving me any sort of edge on my tracking and mixing.

Three times the price of a Radio Shack SPL meter? Nope, that won't get
you there. Three times the price of a Radio Shack meter wouldn't even
buy the Fiberglas that everybody needs. Making a slightly more
accurate measurement isn't going to help your tracking and mixing,
because you can't fix it as accurately as you could measure it.

As I said before, I've made a career choice. My goal is to deliver
professional results and excellent customer service to clientelle.

A noble goal. What are you starting from, and how much money have you
got? If it's a bedroom and $200, you'd better stick to projects that
you can get professional results using headphones.

Since I lack a degree in electrical engineering, I will be teaching myself
that as well.

You really don't need to know a lot of electrical engineering. Ohm's
Law will get you about as far there as you need to go. You do need to
understand SYSTEM engineering, however. That's the study of gozintas
and gozoutas and how to make them play nicely together.

[Scott Dorsey]

AbsenceStudios wrote:
"Scott Dorsey" wrote in message
...
The RS meter is probably useful for relative measurements, but it's likely
nowhere nearly as good as it could be for the price.

True, but the next step up is the Pro-Tek which is three times the price.

I'm willing to pay three times the price for something that has any chance
of giving me any sort of edge on my tracking and mixing.

It won't give you any edge, really. The room problems you're going to
want to deal with first are problems that are so severe, when you play
swept sine tones and move your head around the room, you're going to
wonder how you even survived.

Do that first, then worry about the rest of it.

When you have room modes that are 25 dB from peak to trough, as is not
unusual in a small room without bass trapping, making sure that your
meter is accurate to within 3 dB is not very important. Play the sweep
tones back, use your ears, move around, and you will immediately know
what I'm talking about.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[AbsenceStudios]

"Mike Rivers" wrote in message
...
On Mar 31, 5:43 pm, "AbsenceStudios" wrote:

As I said before, I've made a career choice. My goal is to deliver
professional results and excellent customer service to clientelle.

A noble goal. What are you starting from, and how much money have you
got? If it's a bedroom and $200, you'd better stick to projects that
you can get professional results using headphones.

=========================

I don't have a budget worked out for acoustics yet--my price ceiling will
probably end up being a little over $5,000.

=========================

Since I lack a degree in electrical engineering, I will be teaching
myself
that as well.

You really don't need to know a lot of electrical engineering. Ohm's
Law will get you about as far there as you need to go. You do need to
understand SYSTEM engineering, however. That's the study of gozintas
and gozoutas and how to make them play nicely together.

=========================

I'm an IT technician. Systems come naturally.