Are audio companies all involved in a huge conspiracy? - Page 40

1 watt into 8 ohms is 2.83 volts. 1 volt into 8 ohms is 125 milliwatts or 0.125 watts. 90 dB below 1 watt into 8 ohms is about 90 microvolts.

The above seems to be based on analog domain signal processing inside the AVR.

The architecture of your average AVR is that the DSP which does all of the signal processing including volume setting drives the DACs which drive the power amps. Modern DSPs can be negligible sources of noise since they run entirely in the digital domain.

There is usually an analog I/V converter and gain stage between the DACs and the power amps depending on the voltage gain in the power amps and other factors. This analog stage is fairly easy and economical to make in such a way that its contributions to system noise are very low.

One important point is that if the AVR is used with a digital source which is now common practice, the AVR volume control's influence on output noise may be very slight or nil when the digital source is itself muted or replaced with a dummy source.

As mentioned earlier, the (analog) power amp stage can have noise output that is down in the dozens of microvolts range. 90 microvolts from a few paragraphs back is fine. The DAC can thus be the determining factor when DACs with dynamic range < 95 dB are used which is fairly common in low and mid-line AVRs. The up-market AVRs I've looked at use ca. 110 dB parts which is similar to common practice in professional audio gear.

D'oh. Yes, thanks for the correction. Now I will return the favor: The volume controls are done in analog stages after the DAC.

To clarify, I'm playing the analog outputs of the 95 into the analog inputs of the 886, The distortion and noise measurement are related to the analog inputs and outputs of the 886, DAC's on the 886 bypassed. So these measurements may be thought of as applying to a line level analog preamp.

I assume that you are talking the master volume control.

Are the individual speaker / channel trim adjustments also made in the analog domain?

You may remember my original post indicated I spent time here trying to decode the complicated 886 operation. You question is one I don't know the answer to, but the setting on the input selector is direct and cd/analog. In order for the gain control to be in the digital domain, the analog signal from the 95 would have to be redigitized processed and then put back into the analog domain. That would seem to defeat the purpose of the dedicated analog inputs. I'll see if I can find the answer in the 886 thread.

Yes. In fact in the same gain element. The uP keeps track of how to allocate MV, gain trims, and other housekeeping offsets.

Thanks. Saves me looking.

I'm looking at an Onkyo service manual whose analog and D/A section covers the TX-NR3009, TX-NR5009, PR-SC5509, Integra DTR-70.3, DTR-80.3, and DHC-80.3. They use the Cirrus CS-3318 chip (PDF file), an 8-channel analog volume control providing gain from -96dB to +22dB in 0.25dB steps.

Arny,

Whatever you are doing to reply is not working correctly. You made it look like all the stuff you wrote came from me. You can fix it with a close quote.
You are going to show average AVR schematics that have the volume controls in the DSP? Please do so.
Of course not.
It does not require a mechanical control to do remote volume.

Take a look at the Cirrus CS3318. Or the TI/BB PGA4311, or the Rohm BD3814FV. I have seen all these parts in AV processor use. They are cheap and they track perfectly. More to the point, the are 100% analog signal path in to out.

To you and Roger: Your are both right and I am wrong. I was actually looking at that exact service manual, but I took the 3318 for what the schematic showed - op amps. if I was thinking I might have noticed that the 3318 is numbered like other Cirrus Analog gain control chips going back to the 3310, an early stereo chip of some fame.

I confirmed this with several other service manuals: High quality analog switches and volume controls typically follow the DSP. My apologies for arguing something different.

No biggie Arny. BTW, I think that's a pretty impressive chip. Although this is probably a good bit of marketing, there's an interesting write-up on its predecessor, the 3310, here. I like the fact that for gains less than or equal to 1, the op-amp runs at unity gain, so it's not doing the "attenuate, then boost" thing that typical analog preamps do. Also, according to that article, the op-amp gets progressively decompensated as its gain increases (with 10dB increments for the decompensation) to keep the distortion low as gain increases. Nice touch.

Compare that technology to the kludgy stuff with relay-controlled attenuators and such in "high end" products.

Yes, and the motor-driven potentiometers.

Yes, indeed. Looking at other products one sees far more complex chips like this one that I found in the SM for a competitive AVR:

http://semicon.njr.co.jp/eng/PDF/NJU72340A_E.pdf

I am frankly surprised that current AVR architecture is still this analog-centric. On the one hand the fact that the same basic architecture is implemented over such a wide range of products with a wide range of prices is pretty interesting. I'm guessing that the cost of 8 channel DACs with enough dynamic range is part of the picture. The existing analog-centric architecture can (and does) deliver good overall performance with relatively mediocre DACs. DACs with > 110 dB dynamic range would be required to bypass the analog volume control and etc and those parts are only recently coming down in price.

As long as there is a desire for an analog bypass of the DSP, the analog selector switch and volume control are firmly entrenched. There appears to be a lot of fear and loathing of all-digital solutions, even though this path delivers superior performance every where it is exploited.

To put this into perspective, a Sansa Clip is a fully functional high quality FM stereo receiver with built in digital music player and multi-gigabyte media library, lacking only power amplifiers capable of driving speakers. About $30 in the right store and with the footprint of a postage stamp. Its size could be smaller except for the need to have operable controls and a readable display.

at least its not a bose thread.

That's because everyone knows audio quality is relative to pounds.

£s and/or $s.

Interesting thread, read some but not nearly the whole thread. So the argument is basically there is a point reached with gear, especially amps and DACs that the performance is as good as the ears can detect, right?

So the higher end gear is just over built "audio jewelry" backed by fancy reviews and false claims that can be proved wrong from DBT procedures?

Is there a recommended gear list for readers? A list of gear choices that are good enough, without waisting money on "better" and more costly gear that can be proved no better from testing?

I would be interested in trying some modern gear (mainly amplification) that would be at this level of performance to compare to my set up. I also see a lot of talk of the benefits of Audyssey equalization, is this
recommended for two channel or just multi channel set ups?

I guess I could of fallen to the hype of overbuilt high-end gear but I am happy with my sound system. But It would be interesting to me to try a amp set up that is considered to be at the point of "good enough" plus I would remove all my "better cables" and replace with plain old speaker wire and component supplied RCA cables as part of my experiment.
Edited by Todd68 - 1/10/13 at 12:37pm

That's the bottom line, if the design goal is accurate sound reproduction.

The best thing to do with gear is do your homework, learn what's really audible and if there's a reason for the gear you're looking at to provide a difference.
There's more to gear than just audio quality at play such as build quality, aesthetics and cost.
No one here is saying don't buy high end gear, they're saying you don't have to to get accurate audio, and more importantly that high end gear tends to "over-state" the difference you actually get for the dollar, and even worse some outright lie in their marketing.

As for Audyssey, I'm a huge fan of it, I use it for all my sources regardless of number of channels. But, there's other RC's on the market too, it's not the only kid on the block.
You will typically get more bang for your audio buck addressing the room/speaker interaction than any component change.

Start with getting the bass right, and work up from there.
Edited by rnrgagne - 1/10/13 at 5:03pm

Yes, and that point comes a lot lower on the price spectrum than you might think.
The jewelry analogy is a good one. A lot of high-end audio products are like high-end watches—they cost more, but don't tell time any better. But it's no more "wrong" to buy high-end audio gear than to buy a Rolex.
No, such a list would be impossible to produce and useless anyway. You're much better off with a set of rules to follow: Decide on a budget. Devote most of that budget to speakers. Pay attention to room issues, with either treatments or room correction or both. And have a little fun, because bottom line it simply isn't the most important decision you have to make in life.
It, and other room correction tools, can help for two-channel as well.
You might be interested in this experiment. (Click Blind Tests, then the link.)

I agree. No electronics no matter how expensive can compensate for the wrong speakers, how they're set up or the room itself.

Only after the room is correct and the proper speakers are being used should someone select the components to make up the rest of the audio system.

No one should have to buy the ultra $$$ electronics to get the best possible sound.

In my current system I probably have around $2,000 - $3,000 invested and I get excellent sound.









I also have maybe $500 if not a bit less in my work stereo system and get great sound with it as well.

I read some of the matrix hifi link, until I got bored and a headache LOL! No wonder most couldnt tell any difference, this sort of thing would not be enjoyable experience. It doesn't prove anything to me that I didnt already know, higher price doesn't always equal higher performance.

Is the Audyssey available as stand alone unit I could use with my existing gear? I guess I should read the dedicated thread to learn more.

Cheers!

 

You could try to find a secondhand SVS AS-EQ1 (they are discontinued since XT32 became available in AVRs). The AS-EQ1 gives you the equivalent of XT32 (the top of the range Audyssey consumer correction) but for the bass frequencies only. But is in the bass that you need EQ the most so the audible difference with the unit in place is astonishing. The EQ1 will work with any form of room correction you already have. Alternatively, the Anti-Mode is a well-regarded bass EQ device and that is still in production.

 

You are right to be thinking the way you are now (and what a change from that other thread we chatted in!) - concentrate on the speakers, the room (with physical treatments or EQ, or both if possible) and you will hear very big differences in your SQ. Unless your amps cannot drive your speakers properly, to the SPL levels you need, without clipping, then forget amps for now. And totally forget 'magic' cables, 'superior' DACs and all that phooey. This will give you the best possible SQ without you wasting any money.

 

If you do need amps now (because you current amp/s cannot do what I say above) then look at Emotiva. Their amps are well made, measure well and in an blind ABX test could not be distinguished from any other competently designed amp working within its design limits. And they are very affordable.  But get the room and the speakers right first.

Thanks for the into! I am sure my amps are good enough. I have read about the Anti-Mode device so I might go with that.

Cheers!

Better. Several of us have done experiments where we cascaded DACs and power amps to see how many times music can be amplified or converted without any audible change. For amps the answer is on the order of 5 times, while for really good DACs the answer is upwards of 20 times. Despite all the wailing and gnashing of teeth DACs are among the most highly perfected kind of audio gear there now is. It wasn't always that way but DAC chip technology follows semiconductor technology which is continuing to advance rapidly.

True except much modern high end gear isn't even over built that much. For example Onkyo has two lines of AVRs, one under their name for the mass market and one under the Integra name for the high end installed system market. Comparison of the service manuals and the equipment itself shows no significant differences.

That list would be very dynamic, and prone to become obsolete at the drop of a hat. The AVS forums seem to be a good conduit for that kind of information. There is a rich history of old threads that is still online.

Audyssey is good wherever you can apply it.

Buy the cheapest AVR you can find with Audyssey XT32. It is probably a Denon or Onkyo. Check the relevant AVS threads to make sure that the user experience with the particular model you want to buy is good.

There is also the Audyssey Sound Equalizer (SEQ), an 8 channel stand-alone unit they had out a while back which might be findable used, the only negative is that it's limited to the XTplatform. But it is very good none the less.

I made no response since (1) my observations were made about the Integra  DTC-9.8 which is supposed to share all analog features with the Integra 9.9, Onkyo 885 and Onkyo 886, (2) the observations were based entirely on subjective auditions with the 9.8 which I owned for several years (so no one need make snide comments cost issues) and (3) the measurements are what they are and stand for themselves. Others have expressed similar comments about the 9.8/885 and the 9.9/886. You can ignore my comments entirely if you are willing to rely entirely on objective measurements or you can listen for yourself.

There used to be an active thread here on AVS regarding the Anti-Mode. I don't think there has been much activity lately but it is still a useful source of information.

The general consensus seems to be that it is a very good product, particularly for those who have neither the time nor interest to take a more proactive hands-on approach to bass correction. The Anti-Mode can get you far (in the right direction) on its own with hardly any effort required from its owner.

Thanks, I did read some about the device and it seems like good alternative.

A possible point of coincidence exists between Mr. Rubinson and Hi Fi World may be found in the following passage from the Hi Fi world review:

"An analogue input signal through the A/D can exceed no more than 1.96V, a limit avoided by selecting Direct or Pure Direct."

Many digital players and have analog outputs > 2 volts which could stimulate clipping and poor sound quality in the Onkyo 886.

The phono section of the 886 is capable of about 5 volts RMS which is >> 2 volts (re: analysis of the SM). So, you can clip it out via its own phono section.

Mr. Rubinson?  Why so formal?