Analog Attenuator?

[sandyk]

Unless Chris has some other requirement that he hasn't mentioned, such as the need for longer length interconnects,
all that he appears to need has been discussed previously.

https://goldpt.com/
Precision Balanced Level Controls

 

He doesn't need an Active buffer etc.
An attenuator such as above will permit the retention of the full available bandwidth of the present amplification,
without the LF of the signal being further degraded by transformer limitations, additional phase changes,
 and the inevitable reduction of HF performance where the amplifier has a wide bandwidth,
with members such as Miska believing that a well implemented amplifier with a bandwidth as high as 1MHZ sounds better.
 This is even more important to take full advantage of the higher resolution formats such as 24/192 and DSD,
 where ideally you should also have speakers that have a usable bandwidth to at least 40KHZ.
Using just an attenuator such as above will also permit the use of direct coupling to the source,
which may result in S/N improvements and a more precise sounding LF performance that you can feel.
It's normally best to keep additional Active devices,transformers and coupling capacitors out of the signal path wherever possible,  unless you need to use way longer length interconnects than desirable due to equipment layout problems.

[JohnSwenson]

2 hours ago, The Computer Audiophile said:

Thanks John. Is the autoformer similar at all to what The Bespoke Audio Company is doing with its transformer design?

 

https://www.thebespokeaudiocompany.com/our-product

 

 

 

They don't say they use autoformers so I presume they are transformers. In general autoformers have wider frequency range and flatter frequency response, but are lot galvanically isolated. True transformers are galvanically isolated. As with anything a really good transforer can have better response than a so so autoformer, but a really good autoformer will propbably outperform a really good transformer. The autoformers are usually smaller and less expensive than a true transformer.

 

John S.

[Kal Rubinson]

7 hours ago, bbosler said:

Really? I think this may be one of the least contentious discussions I've ever been involved in. perhaps you are a bit too sensitive?

Agreed,

7 hours ago, bbosler said:

Kal, I can't imagine a setup where you can't get your sources closer to the front than 30 feet.

Drop in next time you are in NYC...........

7 hours ago, bbosler said:

f you are locked into that, then you might try the preamps for those channels in the front at the end of the 30 foot run from the source and short cables from the pre to the amps so the attenuation is at the end instead of the beginning. Run a 30 foot cable from your IR repeater to those preamps.

The repeaters are not reliable, even over shorter distances.  That is what I used with the multple Benchmark LA4s.

7 hours ago, bbosler said:

Interestingly, if you are using the Parasound A31amp up front, the Benchmark preamp has a lower input impedance than the amps so in that regard you are better off with the preamp driving the long cables. .

Nope.  I use Benchmark AHB2s up front.

 

7 hours ago, bbosler said:

Even the ones that have a single set of 7.1 inputs digitize the analog to be processed so for me that would be a non-starter.

Not true.  I have a Marantz AV8805 in my other house and its 7.1 analog input is analog all the way.

 

7 hours ago, bbosler said:

Your solution of running a bunch of stereo preamps, whether Benchmark or some others,  looks to be the only solution other than the possibility of a pro audio sound console used for mixing. Maybe what  the pros use to mix/create the multichannel recordings ??

I could fall back on the SPL SMC 7.1 Surround Monitor Controller but it has its drawbacks.

[The Computer Audiophile]

I should note that I’m using 40 feet long interconnects from my preamp to my mono amps. The cable is from Gotham. 

 

specs:

Gotham GAC-4/1 11301 ultraPro XLR, starquad balanced single channel 5 times shielded audio cable! Ultraflexible professional audio cable for microphones. 'Double Reussen shield', velvet matte non-light reflecting PVC-jacket material. A unique construction new invented by Gotham design

Connector: Neutrik 3Pin Gold-plated XLR(M/F) Plugs

 

https://www.ghentaudio.com/part/x01.html
 

https://gothamcables.com/en/gothamcables/starquad/11301gac41ultrapro

 

GAC2017page09.pdf

[sandyk]

3 minutes ago, The Computer Audiophile said:

I should note that I’m using 40 feet long interconnects from my preamp to my mono amps. The cable is from Gotham. 

 In which case, IDEALLY , the Preamp should be capable of  driving the impedance of the cable using a suitable series output resistance value, with a terminating resistor of that value across the inputs of the power amplifiers. The penalty would be half the input voltage to the mono amplifiers, but with no HF rolloff.

This would be similar to correctly implemented Video distribution.

[tmkirst]

14 hours ago, Kal Rubinson said:

Two channels only.

 

In my setup, they go to the front L/C/R amps and speakers.

 

The Benchmarks come close enough for me.

My mistake then, responding to the original post:

 

I only need a single XLR input and single XLR output. 

 

I see Sonore has its analog attenuator, but it's unbalanced only. 

 

$59 at B&H Photo. What's to lose?

[Kal Rubinson]

53 minutes ago, tmkirst said:

I only need a single XLR input and single XLR output. 

Yes, one input and one output.  Generally, that means two channels but, for me, it means 6-8channels from one source.

 

Quote

 

I only need a single XLR input and single XLR output. 

 

I see Sonore has its analog attenuator, but it's unbalanced only. 

 

$59

[Summit]

5 hours ago, The Computer Audiophile said:

I should note that I’m using 40 feet long interconnects from my preamp to my mono amps. The cable is from Gotham. 

 

specs:

Gotham GAC-4/1 11301 ultraPro XLR, starquad balanced single channel 5 times shielded audio cable! Ultraflexible professional audio cable for microphones. 'Double Reussen shield', velvet matte non-light reflecting PVC-jacket material. A unique construction new invented by Gotham design

Connector: Neutrik 3Pin Gold-plated XLR(M/F) Plugs

 

https://www.ghentaudio.com/part/x01.html
 

https://gothamcables.com/en/gothamcables/starquad/11301gac41ultrapro

 

GAC2017page09.pdf 80.27 kB · 0 downloads

 

40 feet long interconnects will degrade the sound quality no matter which type of preamp or attenuator you use. For such long distance I believe balanced interconnects is the most important if the rest of your audio gear has balanced in- and outputs.

[Summit]

14 hours ago, bbosler said:

 

Really? I think this may be one of the least contentious discussions I've ever been involved in. perhaps you are a bit too sensitive?

 

 

we've never met unless you consider this to be meeting. If you do then you just met one. minus the tears. In addition, there are thousands of people with the funds to do otherwise who prefer a passive over an active. I don't want to make assumptions about your knowledge and background, but the vast majority of those who hold your views have zero knowledge about how electronics actually work. I'm pretty sure the vast majority of them also speak anecdotally having never done the comparison themselves... I have.

 

An active  preamp is simply a passive volume control (potentiometer, stepped attenuator, transformer, etc) and a line level amplifier that may or not have gain. The active stage is usually, almost always, after the volume control to act as a buffer i.e. an impedance matcher that presents a high impedance to the volume control and therefore the source while having a low output impedance to drive the amp. Some put an active stage before and after the volume control and a few put it only before. .  If the source is capable of driving the power amp directly, which many of them are, and the power amp has a relatively high input impedance, which most of them do, then all you may achieve by adding an active preamp is to add coloration. Granted, you may prefer that coloration, but it will be there.

 

Many DACs and other sources are perfectly capable of driving a power amp. Many are designed to do just that with a built in volume control. Most, like the Rossini, control the volume in the digital domain so I prefer to do it after the DAC once the D to A is complete.  DCS even recommends avoiding the use of too much digital attenuation.

 

Kal, I can't imagine a setup where you can't get your sources closer to the front than 30 feet. No need to go into all of the reasons why, but if you are serious about this, and from all I can see you are indeed very serious, of all the compromises we have to make in this hobby running 30 foot cables to my main channels would be at the bottom of my list. If you are locked into that, then you might try the preamps for those channels in the front at the end of the 30 foot run from the source and short cables from the pre to the amps so the attenuation is at the end instead of the beginning. Run a 30 foot cable from your IR repeater to those preamps. The downside is the source has to drive the long cable which may be worse, but you won't know until you try it. You waste a preamp channel doing it that way unless you run a long cable back to the surround channel amp, but a small price to pay for maximum fidelity if it turns out to be better. Interestingly, if you are using the Parasound A31amp up front, the Benchmark preamp has a lower input impedance than the amps so in that regard you are better off with the preamp driving the long cables. .

 

regarding your options, I see that you have none when it comes to multiple input 7.1 AVRs and preamps. Even the ones that have a single set of 7.1 inputs digitize the analog to be processed so for me that would be a non-starter. I would also advise against the custom Placette I proposed since when you decide to move on, and you will move on, you will have a $10K+ boat anchor that isn't heavy enough to serve that purpose. If you decide to try Placette I would get multiple stereo units and use like  the Benchmarks. Your solution of running a bunch of stereo preamps, whether Benchmark or some others,  looks to be the only solution other than the possibility of a pro audio sound console used for mixing. Maybe what  the pros use to mix/create the multichannel recordings ??

 

I don’t think we are discussing the same thing. I/we are not discussing then the source is capable of driving the power amp directly. Connecting a preamp to a top DACs like DCS and MSB always comes with some penalty. What we are discussing is the situation then you have a good DAC that doesn’t have a volume control and pros and cons of different alternatives for changing the volume.

 

I guess that it must mean that you believe that all the manufacturer that makes some of the best amplifiers also has zero knowledge about how electronics actually work. Or why else would they use active preamps instead of passive ones, and not only in their dedicated preamps but also in their top integrated amps.

[The Computer Audiophile]

4 hours ago, Summit said:

 

40 feet long interconnects will degrade the sound quality no matter which type of preamp or attenuator you use. For such long distance I believe balanced interconnects is the most important if the rest of your audio gear has balanced in- and outputs.

Can you back that up with any other information?
 

40 feet isn’t really that long. Every recording studio I’ve ever been to has cables well over 40 feet. In fact, I’d be surprised if any recording I own was done with shorter cables. 
 

All my interconnects are balanced. 

[Kal Rubinson]

5 hours ago, Summit said:

I guess that it must mean that you believe that all the manufacturer that makes some of the best amplifiers also has zero knowledge about how electronics actually work.

That is not valid argument.  They do not possess any secrets that are not readily accessible to any technically-informed individual but they do have commercial interests that are different from those of the consumer. I take their offerings for what they are but I am wary of accepting (or inferring) their reasons for what they do.

 

That said, I can deal with either an active or a passive solution if it is successful for my situation if it is based on electronic principles and actual performance.  So far, the most practical solution (and the one in use) is a digital control.

[PeterSt]

1 hour ago, The Computer Audiophile said:

40 feet isn’t really that long.

 

As long as you realize that any means of analogue attenuation degrades the sound first. 
Indeed 40 feet isn't long, but it is to be tested against a shorter length without aanalogue attenuation or gain (but use a good drive-means first).

 

40 feet of SE cable can easily be totally harmless, BUT use a cable with 5MHz bandwidth capability over more than 300 feet. Next do the math (at say 0.5dB roll off at 1MHz over that distance).

Balanced would be better if the bandwidth is comparable (I don't recall Gotham giving those specs) BUT which also includes the shielding of especially the SE cable (in the end the shielding of the Balanced cable just the same).

And thus remember, start out with an attenuator of any means that I know of, and you can buy cheap cables just the same.

 

I see a lot of apples and oranges here.

 

Something else:

Does anyone want to see the frequency response of a Placette ? You don't want to see that.

The internals of it then ? you definitely don't want to see that.

 

I never could make a satisfying analogue attenuation means. They *all* influence linearity on the frequency response, no matter what type. Voltage control of the D/A chip is the only solution.
Let me add to this that anyone who thinks that a balanced attenuator does not harm THD (wildly) ,,, please explain the "why not" of that. It just can't exist, not even with a differentially setup voltage controlled D/A chip. You can make "a best" all right, but it will always be worse (easily measurable on the THD alone) than a well done digital attenuator (and I mean purely in the digital domain - hence in-software).

 

My 2c.

Peter

 

[Summit]

1 hour ago, The Computer Audiophile said:

Can you back that up with any other information?
 

40 feet isn’t really that long. Every recording studio I’ve ever been to has cables well over 40 feet. In fact, I’d be surprised if any recording I own was done with shorter cables. 
 

All my interconnects are balanced. 

 

If you do a search on internet you will find a lot of different recommendations. The best IMO is to test this ones and for all yourself, it’s easy if you don’t feel the need to do it blind. I did this more than 25 years ago than it started to come balanced gear for audiophiles. The recording studio was often used as an example on where balanced cables would make a different 😜. We tested short (1,5m ) balanced vs SE cables, then we tested longer (10 meter) balanced vs SE cables and lastly short SE vs long SE then short Balanced vs long balanced. All cables was the same model.

 

We also did a blind test to see if we could distinguish a long balanced from a long SE and a cheap balanced from an expansive balanced. Let say that before that day I was sceptical to both balanced on short cables and that IC could make such a SQ difference.

 

I guess that my experience mean little to you so here is a quote and a few links to back up what I said.

 

Interconnect Conclusions:

One conclusion from these graphs is that when inexpensive interconnects are used, they should be seven feet or shorter. It also shows that optimized interconnects, such as the Microdynamic can be up to 30 feet long before significant phase degradation occurs and more than 100 feet before significant frequency response degradation occurs. The other considerations mentioned previously, including ground-loop noise and poor signal-to-noise environment dictate that it might be prudent to limit these lengths even further. A fudge factor to compensate for these other effects can be applied to get a more realistic prediction of performance. Empirical Audio suggests cutting the guideline in half, which results in inexpensive interconnects having a useful maximum length of about one meter. Optimized high-end interconnects will have a useful maximum length of about 5 meters. Listening tests are highly recommended.

 

http://www.empiricalaudio.com/computer-audio/audio-faqs/short-versus-long-cables

 

https://www.gcaudio.com/tips-tricks/cable-length-and-the-effects-on-sound-quality/

 

https://www.nordost.com/faqs-length.php

 

[PeterSt]

This is not really a serious post - so just as well skip please :

 

20 hours ago, bbosler said:

Many DACs and other sources are perfectly capable of driving a power amp. Many are designed to do just that with a built in volume control. Most, like the Rossini, control the volume in the digital domain so I prefer to do it after the DAC once the D to A is complete.  DCS even recommends avoiding the use of too much digital attenuation.

 

Exactly that won't happen without (severe) THD degradation.

How the remainder of that sentence is consistent with this emphasized part ... hard to see for me. How it is consistent (your message) with the preceding paragraph ... hard to make up (again, for me). Thus :

 

20 hours ago, bbosler said:

If the source is capable of driving the power amp directly, which many of them are, and the power amp has a relatively high input impedance, which most of them do, then all you may achieve by adding an active preamp is to add coloration. Granted, you may prefer that coloration, but it will be there.

 

I surely agree with that. But how to now read the "Many DACs" section, is a bit difficult.

But from your first quote we should conclude that a volume control after the D/A section (in-DAC) is better than digital attenuation (which is NOT the same as in-software, but which could happen at the same level (domain) in-DAC (and then multi-channel ??) ... and which I would like for good principles ... while the VC after the D/A really should be the same as an external VC, often built into pre-amps.

... and which you seem to dislike.

 

Not that anyone will be capable to follow my texts. Ha !

(just saying)

 

[Summit]

41 minutes ago, Kal Rubinson said:

That is not valid argument.  They do not possess any secrets that are not readily accessible to any technically-informed individual but they do have commercial interests that are different from those of the consumer. I take their offerings for what they are but I am wary of accepting (or inferring) their reasons for what they do.

 

That said, I can deal with either an active or a passive solution if it is successful for my situation if it is based on electronic principles and actual performance.  So far, the most practical solution (and the one in use) is a digital control.

 

A beg to differ, what they do and not what they says are valid arguments IMO. The type of design they use is of course what they believe to be the best, and some of them have tried many different designs. On a competitive High End market companies can’t afford not to make as good gear as they can (sorry for the double negative here). All companies do operate on the same market and share the same commercial interests. If you believe that they have some agenda regarding passive/active preamplifying that’s your problem and is noting am interesting in discussing any further.

 

Happy Easter!

[The Computer Audiophile]

44 minutes ago, PeterSt said:

 

As long as you realize that any means of analogue attenuation degrades the sound first. 
Indeed 40 feet isn't long, but it is to be tested against a shorter length without aanalogue attenuation or gain (but use a good drive-means first).

 

40 feet of SE cable can easily be totally harmless, BUT use a cable with 5MHz bandwidth capability over more than 300 feet. Next do the math (at say 0.5dB roll off at 1MHz over that distance).

Balanced would be better if the bandwidth is comparable (I don't recall Gotham giving those specs) BUT which also includes the shielding of especially the SE cable (in the end the shielding of the Balanced cable just the same).

And thus remember, start out with an attenuator of any means that I know of, and you can buy cheap cables just the same.

 

I see a lot of apples and oranges here.

 

Something else:

Does anyone want to see the frequency response of a Placette ? You don't want to see that.

The internals of it then ? you definitely don't want to see that.

 

I never could make a satisfying analogue attenuation means. They *all* influence linearity on the frequency response, no matter what type. Voltage control of the D/A chip is the only solution.
Let me add to this that anyone who thinks that a balanced attenuator does not harm THD (wildly) ,,, please explain the "why not" of that. It just can't exist, not even with a differentially setup voltage controlled D/A chip. You can make "a best" all right, but it will always be worse (easily measurable on the THD alone) than a well done digital attenuator (and I mean purely in the digital domain - hence in-software).

 

My 2c.

Peter

 

Hi Peter, thanks for the post. Part of the fun of this audio journey is reading the different opinions and trying things out for oneself. 
 

I’m very interested in both analog and digital attenuation. I will start a thread for digital attenuation. 

[The Computer Audiophile]

As promised - 

 

 

[Kal Rubinson]

2 hours ago, Summit said:

If you believe that they have some agenda regarding passive/active preamplifying that’s your problem and is noting am interesting in discussing any further.

I do not but I also do not see any deeper implications in any choice they make.

[bbosler]

17 hours ago, Kal Rubinson said:

I have a Marantz AV8805 in my other house and its 7.1 analog input is analog all the way.

 

Everything else it does in the digital domain. I can't believe that this unit has 8 analog volume control channels for these 8 inputs and just passes the signals through. Isn't it capable  of applying Audessy (sp?) correction, EQ, etc.  to these inputs?  If so, wouldn't that prove they are converted to digital?

 

I am happy to say I am wrong but would like to see some proof of that. Don't waste your time if you don't want to.. just curious

[Kal Rubinson]

59 minutes ago, bbosler said:

Everything else it does in the digital domain. 

Yes.

59 minutes ago, bbosler said:

I can't believe that this unit has 8 analog volume control channels for these 8 inputs and just passes the signals through.

It uses a digitally-controlled multichannel analog attenuator for all channels and the analog input bypasses all except this device and the output drivers.

59 minutes ago, bbosler said:

Isn't it capable  of applying Audessy (sp?) correction, EQ, etc.  to these inputs? 

Of course, not.

59 minutes ago, bbosler said:

If so, wouldn't that prove they are converted to digital?

If so but  no.

 

59 minutes ago, bbosler said:

I am happy to say I am wrong but would like to see some proof of that. Don't waste your time if you don't want to.. just curious

It is something that has be analyzed to annoyance on relevant HT forums.  I won't spend my time but, if you are curious enough, try looking for it on AVS.

[bbosler]

thanks, I may look at it, but I have a Trinnov Altitude 16 I'm very happy with so no Marantz in my future.. BTW in case you are interested. the Trinnov  16 does not have 7.1 inputs . The 32 channel model does but I'm pretty sure those do get digitized.

[Kal Rubinson]

1 hour ago, bbosler said:

thanks, I may look at it, but I have a Trinnov Altitude 16 I'm very happy with so no Marantz in my future.. BTW in case you are interested. the Trinnov  16 does not have 7.1 inputs . The 32 channel model does but I'm pretty sure those do get digitized.

I did have the Altitude 32-816 for a while and, yes, it has 7.1 analog inputs.  I am certain that these got digitized because why would you buy a Trinnov and not want to use the DSP?  Besides, since it can take digital multichannel from my server via my LAN, why bother with external DACs anyway.  If I was an HT guy, I would have kept the Trinnov.

[acg]

I feel that I am in a position to comment on much of what has been said in this thread because I have experience with most of the stuff that people have mentioned.  I have one of @PeterStPhasure NOS1a dacs with its digital attenuation in computer software.  I have a Placette Active Preamp that Peter has also had in his own hands for evaluation, but not the passive as used by @bbosler, although it uses the same volume control.  I have tried and am still in the process of trying to find a pre-amp that will suit my system and my needs and have built and purchased and assessed a number of solid state preamps with analogue attenuation and I can only conclude that Peter is correct in insisting that the least impact attentuation is done in software through his NOS1a dac...no doubts about it.

 

But that is not the end of the story. 

 

My system includes a very nice turntable with two arms and two phonostages, the NOS1a dac, a computer streaming input, FM radio...plus at least one spare input just in case another source is added down the track (probably Bluray/DVD input).  That is six inputs.  Because I do not graze only in the computer audio paddock the software based digital attenuation is only useful for one-sixth of my sources, effectively rendering it moot.  Hence my need for a preamplifier.

 

My amps are a little bit unusual in that they require 4V+ input to clip, and they have the passive line level crossovers for six-ways at the input to the amplifiers, so it is an unusually complex load for whatever is driving them.  Not to mention that those 6 channels parallel to a circa 5K load...which is low.  So whatever is driving my amps needs more voltage than just about all modern sources output, which means my preamp needs gain, and very low output impedance.  Surely SS gain stages will work?  Sort of, not really, some much better than others, none have been ideal.  Along the way I've been able to try various analogue attenuation options including the switched stepped attenuators (Goldpoint, Khozmo etc.), a couple of implementations of the Muses 72320 chip (which have been good, certainly better than the stepped attenuators in my circumstances) and shortly a simple circuit designed by Bruno Putzey that varies the feedback in a differential opamp gain stage to alter gain and hence volume.  Also on my desk for implementation are some Intact Audio autoformers which based on my experience in other systems will probably be the ultimate solution, as @JohnSwensonand @Superdad have previously testified in this thread.

 

The beauty of the autoformers is that the good ones can handle more than 8V at 20Hz so are able to be used between the source/preamp and amplifier.  They have this wonderful knack in this position of lowering the source impedance as seen by the amplifier as soon as any attenuation is used.  So at -6dB attenuation the source impedance as seen by the amplifier is improved 16 fold, and it increases logarithmically from there reducing to pretty much zero by no later than -10dB attenuation.  Compare that to a stepped attenuator (Goldpoint, Khozmo etc.) used in that position, the impedance seen by the amplifier is increased as you start attenuating and after a while starts to fall again.  What does this all really mean?  Well, it means that with an autoformer volume control, you do not have to limit yourself to gain stages with low output impedance (read: high levels of global negative feedback) if you do not wish to...you have more options in selecting the active linestage/preamplifier circuit to craft the sound you want.  It also means that if you are not caught in the "race to the bottom" of THD and other specmanship, and cannot hear the difference between 0.001%THD and 0.01%, that you have options.

 

So, to summarise my experience, Peters software VC is sonically the best option if your only source is computer audio.  Most preamps I have added to Peters NOS1a dac have diminished the dynamics a little, but there is one Class A circuit that uses the Muses 72320 chip that I could live with at this stage (not perfect, but satisfying).  Yet to check in my system are the variable differential gain stage from BP and the Slagle Autoformer (though I do have prior experience with the autoformers in other systems).  I love the simplicity of the option from Dave Slagle, and due to the nature of autoformers, the flexibility in selecting a gain stage before it.

 

  

[Superdad]

54 minutes ago, acg said:

The beauty of the autoformers is that the good ones can handle more than 8V at 20Hz so are able to be used between the source/preamp and amplifier.  They have this wonderful knack in this position of lowering the source impedance as seen by the amplifier as soon as any attenuation is used.  So at -6dB attenuation the source impedance as seen by the amplifier is improved 16 fold, and it increases logarithmically from there reducing to pretty much zero by no later than -10dB attenuation.  Compare that to a stepped attenuator (Goldpoint, Khozmo etc.) used in that position, the impedance seen by the amplifier is increased as you start attenuating and after a while starts to fall again.  What does this all really mean?  Well, it means that with an autoformer volume control, you do not have to limit yourself to gain stages with low output impedance (read: high levels of global negative feedback) if you do not wish to...you have more options in selecting the active linestage/preamplifier circuit to craft the sound you want.  It also means that if you are not caught in the "race to the bottom" of THD and other specmanship, and cannot hear the difference between 0.001%THD and 0.01%, that you have options.

 

Great post! 

One of the most remarkable aspects I discovered right away when using the Slagle autoformer is the amount of detail and engagement with the music that remains ever when you turn the volume way down. The experience is completely unlike that of even the very best resistor-based attenuator.

[sandyk]

1 hour ago, acg said:

Also on my desk for implementation are some Intact Audio autoformers which based on my experience in other systems will probably be the ultimate solution, as @JohnSwensonand @Superdad have previously testified in this thread.

 

Technical specifications such as Frequency response and Distortion etc. ?