[Vladimir Vassilevsky]

Jan Panteltje wrote:

On a sunny day (Sun, 21 Sep 2008 16:46:27 -0500) it happened Vladimir
Vassilevsky wrote in
Jan Panteltje wrote:
On a sunny day (Sun, 21 Sep 2008 13:41:43 -0500) it happened Vladimir
Vassilevsky wrote in
Jan Panteltje wrote:

I think it should be possible [I could] design powered speakers with a WiFi interface.

How would you synchronize the different channels?

Yes, good point, timestamp would be one way, but that does not solve the delay.
the delay would be fatal in a live application.

Here is the idea: using the power frequency as the common timing
reference. In the local WiFi network, the ping time would be at the
order of 1ms, so all channels could be PLLed to the same half period of
the AC power without an ambiguity. With the sufficient amount of
buffering, that should allow streaming multiple synchronized channels.
Sooo simple... I bet somebody already got a patent on that.

How about this: we give each speaker a GPS.

Yes, something like GPS but it should be 10 times more precise and be
able to operate indoors. Local positioning system is another perpetual
problem; it would be a good thing to have regardless.

It will also send back its position, and the 'mixer' will
then calculate the optimum sound pattern for 5.1.
GPS also has a very precise clock.

Lots of things can be done; however the consumer audio is very sensitive
to the cost. Many suggestions in this thread, although technically
standing, are totally missing this point.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

[Jorden Verwer]

Eeyore wrote:
And a chopper amp has exactly WHAT to do with ultra high quality audio ?
Well, it proves my point.

[John Larkin]

On Sun, 21 Sep 2008 23:09:11 +0100, Eeyore
wrote:



John Larkin wrote:

"Jorden Verwer" wrote:
RichD wrote:
Who do MOSFET sound better than bipolar, as an audio amp output
driver?

The device properties of BJTs are superior to those of MOSFETs in all
respects, except for offset - there MOSFETs have the advantage. Whether you
will actually hear this depends on many more factors.

Offset? Two BJTs of the same part number will have delta-Vbe well
below a tenth of a volt.

IME typically within a 10mV range. That saved a trimpot and the line time to
adjust it on more than one occasion.


A similar pair of mosfets will have Vgs-th
and transfer curves that can differ by a volt or more.

For vertical types, yes. Not for laterals.

Why? The physics is the same... oxide thickness, trapped charge, all
the things that modulate gate threshold.

The datasheets I've seen show a volt or so spread of Vgs-th spec,
plenty enough to defeat simple biasing/balancing schemes for
paralleled devices.

John

[John Larkin]

On Sun, 21 Sep 2008 19:48:17 -0000, "Jorden Verwer"
wrote:

MooseFET wrote:
Radiation hardness
Boundary condition.

Safe operating area
Boundary condition.

Bandwidth
AFAIK, BJTs still hold the world record for cutoff frequency.


No. Google "widest bandwidth transistor" or some such.

John

[Jamie[_2_]]

Jorden Verwer wrote:

Eeyore wrote:

And a chopper amp has exactly WHAT to do with ultra high quality audio ?

Well, it proves my point.


LOL!
good one.

http://webpages.charter.net/jamie_5"

[Phil Allison]

"Chronic Philharmonic"

Similar, but less obvious considerations affect the choice of BJTs and
MOSFETs.

** Which mosfets ?

You must not confuse switching types with laterals.


They have different characteristics,

** Which mosfets ?

You must not confuse switching types with laterals.


and the skilled engineer will exploit them for optimal effect -- sonic
quality, economy, reliability and so on.

** Which mosfets ?

You must not confuse switching types with laterals.


The marketing department will define the requirements for the product
based on the target market, and the engineer will attempt to design a
product that fits within those constraints.


** It don't have to work that idiotic way at all.


In all that I have read here, I have not seen anything that would
consistently make me select MOSFETs over BJTs.

** Which mosfets ?

You must not confuse switching types with laterals.


But I might have a preference based on a *given set* of product
requirements.

** Pigs might fly too.

Wot an posturing old wind bag you are.



...... Phil

[Eeyore]

John Larkin wrote:

Eeyore wrote:
John Larkin wrote:
"Jorden Verwer" wrote:
RichD wrote:
Who do MOSFET sound better than bipolar, as an audio amp output
driver?

The device properties of BJTs are superior to those of MOSFETs in all
respects, except for offset - there MOSFETs have the advantage. Whether you
will actually hear this depends on many more factors.

Offset? Two BJTs of the same part number will have delta-Vbe well
below a tenth of a volt.

IME typically within a 10mV range. That saved a trimpot and the line time to
adjust it on more than one occasion.


A similar pair of mosfets will have Vgs-th
and transfer curves that can differ by a volt or more.

For vertical types, yes. Not for laterals.

Why? The physics is the same... oxide thickness, trapped charge, all
the things that modulate gate threshold.

I'm telling you that's how laterals are in practice.

Better processing perhaps ?


The datasheets I've seen show a volt or so spread of Vgs-th spec,
plenty enough to defeat simple biasing/balancing schemes for
paralleled devices.

Laterals work beautifully like that.

Graham

[Chronic Philharmonic]

"Eeyore" wrote in message
...


Chronic Philharmonic wrote:

"RichD" wrote

Who do MOSFET sound better than bipolar, as an audio amp output
driver?

A lot of bits have been spilled on this thread so far, but I think it is
the
same question as "Why do tubes sound better than transistors?" or "How
many
angels can dance on the head of a pin?"

First of all, it implies a truth that may not objectively be the case.
But
tubes, BJTs and MOSFETs all have very different characteristics and
engineering trade-offs.

Actually, certain mosfets are not at all unlike triodes.

I almost said that, but decided to leave it because many other physical
and/or electrical parameters are distinctly different, and I figured I'd get
flamed for that.

More to the point is whether you are anti-science and despise negative
feedback.
And / or LIKE your music deliberately distorted as some seem to do.

I think negative feedback is an extremely powerful tool in electronic,
economic, social and natural systems. But people don't seem to understand
it, so they don't trust it.

[Trevor Wilson[_2_]]

"Eeyore" wrote in message
...


Chronic Philharmonic wrote:

"RichD" wrote

Who do MOSFET sound better than bipolar, as an audio amp output
driver?

A lot of bits have been spilled on this thread so far, but I think it is
the
same question as "Why do tubes sound better than transistors?" or "How
many
angels can dance on the head of a pin?"

First of all, it implies a truth that may not objectively be the case.
But
tubes, BJTs and MOSFETs all have very different characteristics and
engineering trade-offs.

Actually, certain mosfets are not at all unlike triodes.

More to the point is whether you are anti-science and despise negative
feedback.

**It matters not whether a person despises NFB or not. NFB is present in
every amplifier known to man. There are, however, a variety of ways that NFB
can be applied.


--
Trevor Wilson
www.rageaudio.com.au

[Arny Krueger]

"Eeyore" wrote in
message

Exactly. KRK have a very good name in that respect at the
moment and I think they do actives.

Mackie HR 824 s are almost an industry standard and are active.

Berhinger 2031a are favored by a number of my pickier friends - also
powered.

[Arny Krueger]

"Eeyore" wrote in
message
MooseFET wrote:

isw wrote:

If you want to go all the way to having feedback from
the speaker, it seems to me that moving the feedback
detection as close to the sound output as practical is
the way to go. Sensing actual cone movement is better
than sensing the driven voice coil's voltage.

Philips did that decades ago with a piezo transducer
IIRC. No idea why it didn't take off other than Philips
aren't exactly reknowned for hi-fi.

Paradigm Servo-15

Basstech 7

Velodyne

etc.

There are three logical ways to do this:

(1) Positional feedback, I've seen it done with a laser
(2) Velocity feedback, can be as simple as sensing the voltage on a second
voice coil
(3) Accelerometer feedback

Of the three, using an accelerometer probably makes the most sense, as
velocity and position can be obtained from acceleration by sucessive
integration. The integration can be effective, even when done in the analog
domain.

[Jorden Verwer]

John Larkin wrote:
No. Google "widest bandwidth transistor" or some such.
All that yields is your post.

Okay, sillyness aside, without the quotes it does indeed return some
results. But I couldn't find a definitive answer either way. I do remember
reading about a BJT that had an ft of 500 GHz a couple of years ago, which
was a new record at the time. It's indeed possible that things have changed
since then, although I'd bet that BJTs can't be far behind.

Of course this is all a whole different game than audio, but frankly I think
both BJTs and MOSFETs offer sufficient bandwith in audio applications these
days.

[MooseFET]

On Sep 22, 1:19 am, Vladimir Vassilevsky
wrote:
MooseFET wrote:
If you want to go all the way to having feedback from the speaker, it
seems to me that moving the feedback detection as close to the sound
output as practical is the way to go. Sensing actual cone movement is
better than sensing the driven voice coil's voltage.

The idea of the feedback directly from the cone is no new. The main
problem is economical: it is easier to make a reasonable conventional
speaker rather then trying to make a good speaker from the bad one by
the means of feedback and feedforward compensation.

I wasn't trying to suggest that I had invented the idea, only that I
like the idea.

Silk purse != sows ear holds true for cases with feedback.

Once you have a good speaker, adding local feedback, it seems to me
would back a very good speaker. The 3db points could become 1db
points and the distortion of the low frequencies would be reduced by
about what the loop gain is.




Some years back I
saw a really nice design for a subwoofer that did this. Here is
basically what the design did:

There was no voice coil at all. The cone was moved by a fast servo
motor with a metal belt drive that drove a rod on the cone center..
This allowed motions of several inches but didn't have a very flat
frequency response.

A position sensor on the rod on the cone center and a pressure
transducer where combined to form the feedback signal. The position
sensor couldn't know about the cone flex and the pressure sensor
couldn't know the very low frequency components. The combined signal
covered the entire range of interest.

There was a really massive servo amplifier driving the motor giving
the system the ability to work up to several Hz.

It seems to me that this sort of thing could be done today and make it
up into the 10s of Hz.

In geophysics, they use the powerful hydraulic vibrators which operate
at the frequencies up to 100Hz. It is interesting that the flat response
and the linearity are important for geophysical application; so some
sort of compensation is applied. This technology can be used for the
woofers if we are after the power levels of 10kW or higher.

Vladimir Vassilevsky
DSP and Mixed Signal Design Consultanthttp://www.abvolt.com

[John Larkin]

On Mon, 22 Sep 2008 13:46:44 -0000, "Jorden Verwer"
wrote:

John Larkin wrote:
No. Google "widest bandwidth transistor" or some such.
All that yields is your post.

Okay, sillyness aside, without the quotes it does indeed return some
results. But I couldn't find a definitive answer either way. I do remember
reading about a BJT that had an ft of 500 GHz a couple of years ago, which
was a new record at the time. It's indeed possible that things have changed
since then, although I'd bet that BJTs can't be far behind.

Of course this is all a whole different game than audio, but frankly I think
both BJTs and MOSFETs offer sufficient bandwith in audio applications these
days.


The really fast parts are compound semiconductor heterojunctions,
Phemts and HBT's. The fastest silicon stuff, in the 150 GHz range, is
mostly CMOS. Some next-gen Bluetooth type stuff will be cmos at 60
GHz.

As far as discretes that you can actually buy and do stuff with in
real life, the fastest bipolars are the SiGe parts, in the 45-60 GHz
Ft sort of range, and the fastest fets are things like the NEC Phemts.
In real life, the phemts are faster, because Ft is where a transistor
has a beta of 1, which is semi-useless for most applications,
especially wideband stuff.

True, none of this is relevant for audio. Anything will work for
audio.

John

[Vladimir Vassilevsky]

MooseFET wrote:

On Sep 22, 1:19 am, Vladimir Vassilevsky
wrote:

MooseFET wrote:

If you want to go all the way to having feedback from the speaker, it
seems to me that moving the feedback detection as close to the sound
output as practical is the way to go. Sensing actual cone movement is
better than sensing the driven voice coil's voltage.

The idea of the feedback directly from the cone is no new. The main
problem is economical: it is easier to make a reasonable conventional
speaker rather then trying to make a good speaker from the bad one by
the means of feedback and feedforward compensation.


I wasn't trying to suggest that I had invented the idea, only that I
like the idea.

Silk purse != sows ear holds true for cases with feedback.

Once you have a good speaker, adding local feedback, it seems to me
would back a very good speaker.

Again, it turns out that it is cheaper to make just a very good speaker
rather then making a very good speaker from a good one by means of some
feedback magic. Fixing the origin of a problem is better then finding a
way around a problem.

The 3db points could become 1db
points and the distortion of the low frequencies would be reduced by
about what the loop gain is.

At one time, I was trying to get more usable SPL from subwoofer by
applying the feedforward and feedback corrections by DSP. There was an
improvement of somewhat 2dB. However the result was the rapid mechanical
destruction of the speaker; the heat dissipation was the issue, too.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

[Eeyore]

Arny Krueger wrote:

"Eeyore" wrote

Exactly. KRK have a very good name in that respect at the
moment and I think they do actives.

Mackie HR 824 s are almost an industry standard and are active.

Berhinger 2031a are favored by a number of my pickier friends - also
powered.

No disrespect to the above two, I'm sure they're quite competent, but
'serious' studios won't be using them.

KRKs are very popular at the moment with high end studios for
mini-monitors.
http://www.krksys.com/

Graham

[Eeyore]

Jorden Verwer wrote:

John Larkin wrote:
No. Google "widest bandwidth transistor" or some such.
All that yields is your post.

Okay, sillyness aside, without the quotes it does indeed return some
results. But I couldn't find a definitive answer either way. I do remember
reading about a BJT that had an ft of 500 GHz a couple of years ago, which
was a new record at the time. It's indeed possible that things have changed
since then, although I'd bet that BJTs can't be far behind.

Of course this is all a whole different game than audio, but frankly I think
both BJTs and MOSFETs offer sufficient bandwith in audio applications these
days.

BJTs designed for audio vary very widely in stated fT.

Graham

[Eeyore]

John Larkin wrote:

True, none of this is relevant for audio. Anything will work for
audio.

Almost anything. RCA's 2N3055s weren't exactly the fastest in the world. 800kHz
fT IIRC. I hate to think what their germanium predecessors like the OC35 were
like.

Graham

[Arny Krueger]

"Eeyore" wrote in
message
Arny Krueger wrote:

"Eeyore" wrote

Exactly. KRK have a very good name in that respect at
the moment and I think they do actives.

Mackie HR 824 s are almost an industry standard and are
active.

Berhinger 2031a are favored by a number of my pickier
friends - also powered.

No disrespect to the above two, I'm sure they're quite
competent, but 'serious' studios won't be using them.

Right, they haven't been around for decades and aren't all that costly.

Speaking of reasonably-priced competent but newer monitors, the last two
generations of JBL powered studio monitors are very competent.

KRKs are very popular at the moment with high end studios
for mini-monitors.
http://www.krksys.com/

A friend analyzed a pair and found them to be excessively prone to IM
distortion. Don't remember which model, but any brand that will let stuff
that incompetent out the door deserves a wary look.

[Arny Krueger]

"Eeyore" wrote in
message
John Larkin wrote:

True, none of this is relevant for audio. Anything will
work for audio.

Well, almost everything. ;-)

Almost anything. RCA's 2N3055s weren't exactly the
fastest in the world. 800kHz fT IIRC.

Sounds about right.

I hate to think
what their germanium predecessors like the OC35 were like.

In the US, their germanium predecessors included the 2N2147s, which were
very fragile. Fried a few myself.

Not only were these germanium audio output devices intrinsically fragile
devices, this was also before SOA protection became common.

[Jan Panteltje]

On a sunny day (Sun, 21 Sep 2008 13:41:43 -0500) it happened Vladimir
Vassilevsky wrote in
:


The real 802.11G throughput is 2.8MB/s at the best. An uncompressed
audio channel takes roughly 100KB/s.

That number you give is 100% correct (tested with scp, it reports the speed).

But using UDP (not TCP/IP) we can go faster:

original file:
-rw-r--r-- 1 root root 2473920576 2008-08-23 19:00 goldfinger.ts

Main PC:
date;cat goldfinger.ts | netcat -q 0 -x Maximize-Throughput -u 10.0.0.155 1234;date
Mon Sep 22 21:26:19 CEST 2008
cat goldfinger.ts 3.20s user 32.41s system 12% cpu 4:36.56 total
netcat -q 0 -x Maximize-Throughput -u 10.0.0.155 1234 3.67s user 215.37s system 79% cpu 4:36.56 total
Mon Sep 22 21:30:56 CEST 2008

Other side (eeePC)
netcat -u -l -p 1234 /dev/zero

Completed, file length / total time gives 8.9MB/s
x 8 makes about 70 Mbits / second, clearly something went wrong..... my math?

However, I could not play it, when I tried to write to a RAM cache for speed,
it was all garbled.

UDP = no error correction if packet not received, packet may arrive in any order too.

Anyways, I repeated the test the other way around, now for a mp3 file:
-rw-r--r-- 1 user user 103760023 2008-09-09 19:03 instrumental.mp3

home/user date;cat instrumental.mp3 | netcat -x Maximize-Throughput -u -q 0 10.0.0.150 1234;date
Tue Sep 23 00:17:16 CEST 2008
Tue Sep 23 00:17:40 CEST 2008

That makes 24 seconds for 103760023 bytes, makes 4.32 MB/second, that is
34.58 Mbps.

There is some data loss, as the received file length is: 103579799
But it seems to play very well, the end is also there, but for course
data integrity is bad, there must be damage somewhere, but I listened to part of it,
and that sounded great, but it is too long to listen to all of it now, maybe tomorrow.

[krw[_3_]]

In article ,
says...


krw wrote:

You're going to have to justify that number. 100MB/s?

He said kBps.

Don't know what I was looking at. ...ahead at WiFi??

I can see 20KB, *maybe*.

44.1k samples / sec x 2 bytes each = 88.2kBps. Allow overhead for collisions etc. Actually if
you transmit the full AES/EBU SPDIF data it's THREE bytes.

100kBps sounds about right for one mono channel. Or 150 kBps with flags etc.

Ok, now put three or four of these together and it's still easily
manageable over WiFi.

--
Keith

[krw[_3_]]

In article et,
says...
Jan Panteltje write:
You mean you do not watch TV and listen to radio?
And have no cellphone too?
I mean I try to avoid wireless whenever possible. So when I'm at home, I
watch cable TV and listen cable radio and use my landline phone...


Why? I spent yesterday installing my router into some built-in
cabinets in the great room. The builder put the power outlet in the
top cabinet and all of the LV stuff (phone, Ethernet, and speaker
wires) in the lower cabinet, with a granite slab in between. I
wanted the router on top of the cabinet, where it's out in the open
but can't be seen (from anywhere but the upstairs hall).

--
Keith

[Eeyore]

krw wrote:

says...
krw wrote:

You're going to have to justify that number. 100MB/s?

He said kBps.

Don't know what I was looking at. ...ahead at WiFi??

I can see 20KB, *maybe*.

44.1k samples / sec x 2 bytes each = 88.2kBps. Allow overhead for collisions etc. Actually if
you transmit the full AES/EBU SPDIF data it's THREE bytes.

100kBps sounds about right for one mono channel. Or 150 kBps with flags etc.

Ok, now put three or four of these together and it's still easily
manageable over WiFi.

With Quality of Service and no latency ?

Graham

[John Larkin]

On Mon, 22 Sep 2008 17:55:02 +0100, Eeyore
wrote:



John Larkin wrote:

True, none of this is relevant for audio. Anything will work for
audio.

Almost anything. RCA's 2N3055s weren't exactly the fastest in the world. 800kHz
fT IIRC. I hate to think what their germanium predecessors like the OC35 were
like.

Graham

But they were tough triple-diffused parts. Some other peoples' 3055's,
like the Fairchilds, were epitaxials, very fast but very fragile, and
about half the silicon area.

John

[Eeyore]

John Larkin wrote:

Eeyore wrote:
John Larkin wrote:

True, none of this is relevant for audio. Anything will work for
audio.

Almost anything. RCA's 2N3055s weren't exactly the fastest in the world. 800kHz
fT IIRC. I hate to think what their germanium predecessors like the OC35 were
like.

But they were tough triple-diffused parts. Some other peoples' 3055's,
like the Fairchilds, were epitaxials, very fast but very fragile, and
about half the silicon area.

Were they triple diffused ? RCA called them hometaxial.

The Motorola part was faster but less rugged. Many hobbyists got caught out with
exploding amps by using the wrong brand because JEDEC hadn't specified the devices
adequately and the authors of the articles hadn't thought to look into it.

Eventually, I think Motorola made a 2N3055H to indicate RCA compatability.

Graham

[RichD]

On Sep 19, Eeyore wrote:
Who do MOSFET sound better than bipolar, as an audio
amp output driver?

As a driver ?
Now if you said as an output stage it might make sense.

There's a difference?

Damn right there is.

I'm thinking of the bits that attach to the
copper thingy which loops around the
magnets which make the air move.

An unusual design but the copper thingy is very likely
heatsink, in which case you're referring to the actual output
devices.

The copper thingy is flexible, about 15' long,
attaches to the box with the magnets at one end.

It would indeed be unusual to use that
as heatsink, but perhaps novel and efficient.

They in turn usually have devices called 'drivers'
which precede them, although it's
less necessary with mosfets, only for ultimate performance..

So the output driver feeds the output stage?
Is that the standard jargon?

--
RIch

[Eeyore]

RichD wrote:

On Sep 19, Eeyore wrote:
Who do MOSFET sound better than bipolar, as an audio
amp output driver?

As a driver ?
Now if you said as an output stage it might make sense.

There's a difference?

Damn right there is.

I'm thinking of the bits that attach to the
copper thingy which loops around the
magnets which make the air move.

An unusual design but the copper thingy is very likely
heatsink, in which case you're referring to the actual output
devices.

The copper thingy is flexible, about 15' long,
attaches to the box with the magnets at one end.

I have never seen anything like it. What is the brand ?


It would indeed be unusual to use that
as heatsink, but perhaps novel and efficient.

They in turn usually have devices called 'drivers'
which precede them, although it's
less necessary with mosfets, only for ultimate performance..

So the output driver feeds the output stage?
Is that the standard jargon?

Yes. Somtimes there may be more than one one stage of drivers too. This
is where expertise in amp design comes into play.

Graham

[krw[_3_]]

In article ,
says...


krw wrote:

says...
krw wrote:

You're going to have to justify that number. 100MB/s?

He said kBps.

Don't know what I was looking at. ...ahead at WiFi??

I can see 20KB, *maybe*.

44.1k samples / sec x 2 bytes each = 88.2kBps. Allow overhead for collisions etc. Actually if
you transmit the full AES/EBU SPDIF data it's THREE bytes.

100kBps sounds about right for one mono channel. Or 150 kBps with flags etc.

Ok, now put three or four of these together and it's still easily
manageable over WiFi.

With Quality of Service and no latency ?

Send it a dozen times. Timing shouldn't be too much of a problem.
The clock can be updated periodically. This stuff isn't all *that*
hard, at least good enough for audio.

--
Keith

[Eeyore]

krw wrote:

says...
krw wrote:
says...
krw wrote:

You're going to have to justify that number. 100MB/s?

He said kBps.

Don't know what I was looking at. ...ahead at WiFi??

I can see 20KB, *maybe*.

44.1k samples / sec x 2 bytes each = 88.2kBps. Allow overhead for collisions etc. Actually
if you transmit the full AES/EBU SPDIF data it's THREE bytes.

100kBps sounds about right for one mono channel. Or 150 kBps with flags etc.

Ok, now put three or four of these together and it's still easily
manageable over WiFi.

With Quality of Service and no latency ?

Send it a dozen times. Timing shouldn't be too much of a problem.
The clock can be updated periodically. This stuff isn't all *that*
hard, at least good enough for audio.

Your phrase "good enough for audio" does not inspire confidence. I work in the professional /
production area of audio. 'Good enough' usually isn't for us. Indeed, for a host of reasons I'd also
probably want to transmit 24 bit audio. Some customers might want 96 kHz sampling too.

Go on. Ask why !

Graham

[John Larkin]

On Tue, 23 Sep 2008 08:05:29 +0100, Eeyore
wrote:



krw wrote:

says...
krw wrote:
says...
krw wrote:

You're going to have to justify that number. 100MB/s?

He said kBps.

Don't know what I was looking at. ...ahead at WiFi??

I can see 20KB, *maybe*.

44.1k samples / sec x 2 bytes each = 88.2kBps. Allow overhead for collisions etc. Actually
if you transmit the full AES/EBU SPDIF data it's THREE bytes.

100kBps sounds about right for one mono channel. Or 150 kBps with flags etc.

Ok, now put three or four of these together and it's still easily
manageable over WiFi.

With Quality of Service and no latency ?

Send it a dozen times. Timing shouldn't be too much of a problem.
The clock can be updated periodically. This stuff isn't all *that*
hard, at least good enough for audio.

Your phrase "good enough for audio" does not inspire confidence. I work in the professional /
production area of audio. 'Good enough' usually isn't for us. Indeed, for a host of reasons I'd also
probably want to transmit 24 bit audio. Some customers might want 96 kHz sampling too.

Go on. Ask why !

Graham

Buffer the data. Include a GPS receiver in each speaker to synchronize
the outputs to sub-ns accuracy. That will eliminate those awful cable
prop delays and perfectly coordinate the granularity of the layering
of the holographic soundstaging, or something. The critics will love
it.

John

[Eeyore]

John Larkin wrote:

Eeyore wrote:
krw wrote:
says...
krw wrote:
says...
krw wrote:

You're going to have to justify that number. 100MB/s?

He said kBps.

Don't know what I was looking at. ...ahead at WiFi??

I can see 20KB, *maybe*.

44.1k samples / sec x 2 bytes each = 88.2kBps. Allow overhead for collisions etc.
Actually if you transmit the full AES/EBU SPDIF data it's THREE bytes.

100kBps sounds about right for one mono channel. Or 150 kBps with flags etc.

Ok, now put three or four of these together and it's still easily
manageable over WiFi.

With Quality of Service and no latency ?

Send it a dozen times. Timing shouldn't be too much of a problem.
The clock can be updated periodically. This stuff isn't all *that*
hard, at least good enough for audio.

Your phrase "good enough for audio" does not inspire confidence. I work in the professional /
production area of audio. 'Good enough' usually isn't for us. Indeed, for a host of reasons I'd also
probably want to transmit 24 bit audio. Some customers might want 96 kHz sampling too.

Go on. Ask why !

Buffer the data. Include a GPS receiver in each speaker to synchronize
the outputs to sub-ns accuracy. That will eliminate those awful cable
prop delays and perfectly coordinate the granularity of the layering
of the holographic soundstaging, or something. The critics will love
it.

John

That's certainly an interesting concept. ;~)

Graham

[krw[_3_]]

In article ,
says...


krw wrote:

says...
krw wrote:
says...
krw wrote:

You're going to have to justify that number. 100MB/s?

He said kBps.

Don't know what I was looking at. ...ahead at WiFi??

I can see 20KB, *maybe*.

44.1k samples / sec x 2 bytes each = 88.2kBps. Allow overhead for collisions etc. Actually
if you transmit the full AES/EBU SPDIF data it's THREE bytes.

100kBps sounds about right for one mono channel. Or 150 kBps with flags etc.

Ok, now put three or four of these together and it's still easily
manageable over WiFi.

With Quality of Service and no latency ?

Send it a dozen times. Timing shouldn't be too much of a problem.
The clock can be updated periodically. This stuff isn't all *that*
hard, at least good enough for audio.

Your phrase "good enough for audio" does not inspire confidence. I work in the professional /
production area of audio. 'Good enough' usually isn't for us. Indeed, for a host of reasons I'd also
probably want to transmit 24 bit audio. Some customers might want 96 kHz sampling too.

Yes, I know you're a "professional" audiophool. If you can't hear
it, it's good enough. Fer instance, millisecond is good enough as
long as all channels are together. They all get the same signal.

Go on. Ask why !

Why? I could care less about "professional" audiophoolery. BTW, we
were talking about powered speakers, not "professional" grade audio.
96kHz? What nonsense.

--
Keith

[Don Klipstein]

In article , krw wrote:
In article ,
says...


krw wrote:

says...
krw wrote:
says...
krw wrote:

You're going to have to justify that number. 100MB/s?

He said kBps.

Don't know what I was looking at. ...ahead at WiFi??

I can see 20KB, *maybe*.

44.1k samples / sec x 2 bytes each = 88.2kBps. Allow overhead for collisions etc. Actually
if you transmit the full AES/EBU SPDIF data it's THREE bytes.

100kBps sounds about right for one mono channel. Or 150 kBps with flags etc.

Ok, now put three or four of these together and it's still easily
manageable over WiFi.

With Quality of Service and no latency ?

Send it a dozen times. Timing shouldn't be too much of a problem.
The clock can be updated periodically. This stuff isn't all *that*
hard, at least good enough for audio.

Your phrase "good enough for audio" does not inspire confidence. I work in the professional /
production area of audio. 'Good enough' usually isn't for us. Indeed, for a host of reasons I'd also
probably want to transmit 24 bit audio. Some customers might want 96 kHz sampling too.

Yes, I know you're a "professional" audiophool. If you can't hear
it, it's good enough. Fer instance, millisecond is good enough as
long as all channels are together. They all get the same signal.

Go on. Ask why !

Why? I could care less about "professional" audiophoolery. BTW, we
were talking about powered speakers, not "professional" grade audio.
96kHz? What nonsense.

I occaisionally hear artifacts in 16 bit 44.1 KHz, in music.

It is easy to make a test signal turn up severe artifacts with 44.1 KHz
sample - see what happens with a sinewave at a higher audio frequency that
is several Hz off a frequency that the sample frequency is a multiple of.

Since I only occaisionally hear artifacts in music with 44.1 KHz 16 bit,
and when I do I usually find them minor, I would expect a sample rate
twice as high as that to be OK.

- Don Klipstein )

[Eeyore]

krw wrote:

says...

Your phrase "good enough for audio" does not inspire confidence. I work in the professional /
production area of audio. 'Good enough' usually isn't for us. Indeed, for a host of reasons I'd also
probably want to transmit 24 bit audio. Some customers might want 96 kHz sampling too.

Yes, I know you're a "professional" audiophool.

Just a professional.


If you can't hear it, it's good enough.

Some people's ears are sharper than others. I expect the phone would be good enough for you ?


Fer instance, millisecond is good enough as
long as all channels are together. They all get the same signal.

It wasn't specifically the timing I thought you had in mind.


Go on. Ask why !

Why? I could care less about "professional" audiophoolery. BTW, we
were talking about powered speakers, not "professional" grade audio.
96kHz? What nonsense.

Many top studios are now mastering at 24 bit 192 kHz. Using products like this, reckoned to be the best in
the world and manufactured by another company I used to work for.
http://prismsound.com/music_recordin...da8xr_home.php

Graham

[Eeyore]

Don Klipstein wrote:

krw wrote:
says...

Your phrase "good enough for audio" does not inspire confidence. I work in the professional /
production area of audio. 'Good enough' usually isn't for us. Indeed, for a host of reasons I'd also
probably want to transmit 24 bit audio. Some customers might want 96 kHz sampling too.

Yes, I know you're a "professional" audiophool. If you can't hear
it, it's good enough. Fer instance, millisecond is good enough as
long as all channels are together. They all get the same signal.

Go on. Ask why !

Why? I could care less about "professional" audiophoolery. BTW, we
were talking about powered speakers, not "professional" grade audio.
96kHz? What nonsense.

I occaisionally hear artifacts in 16 bit 44.1 KHz, in music.

It is easy to make a test signal turn up severe artifacts with 44.1 KHz
sample - see what happens with a sinewave at a higher audio frequency that
is several Hz off a frequency that the sample frequency is a multiple of.

Since I only occaisionally hear artifacts in music with 44.1 KHz 16 bit,
and when I do I usually find them minor, I would expect a sample rate
twice as high as that to be OK.

For some reason 88.2 kHz never caught on. It's always been 96, double the 48kHz sampling used in some other
digital audio products, as far as I can remember.

Graham

[Eeyore]

krw wrote:

BTW, we were talking about powered speakers, not "professional" grade audio.
96kHz? What nonsense.

Do you think professionals don't use powered speakers ?

Graham

[RichD]

On Sep 18, Eeyore wrote:
Do you have any experience designing audio amps?

LMAO ! Yes, Kevin had indeed had as have I.
Amps that sold commercially into the
pro-audio market.

Did you use MOSFET on the output stage, and why?



--
Rich

[RichD]

On Sep 19, "Kevin Aylward" wrote:
Who do MOSFET sound better than bipolar, as an audio amp output
driver?

**Non-sequitur. If you're saying that MOSFET outputs sound better,
they don't.
er... yes...e.g.
http://www.studiomaster.com/1984%20-%201986.htm

"This was the amplifier pro sound companies were waiting for;
many buy up to 100 units. "

Did you use MOSFET on the output stage, and why?


--
Rich

[Phil Allison]

"RichD"
"Kevin Aylward"

http://www.studiomaster.com/1984%20-%201986.htm

"This was the amplifier pro sound companies were waiting for;
many buy up to 100 units. "

Did you use MOSFET on the output stage, and why?


** The amp used Hitachi lateral mosfets - egs 2SK176 & 2SJ56.

For technical reasons, that have been stated here and are completely beyond
your infinitesimal comprehension.

You damn troll.



...... Phil