Sonance DSP 2-150 Review (DSP Amplifier)

[restorer-john]

I'm ready to get roasted by you guys on what I could've done better

It's lovely and very well done. I like the bituminous mat to damp the case too.

The only thing is the lack of twisting on the speaker out cable pairs.

 

[amirm]

@amirm you said by resetting the unit there was a bass boost. To get it off did you just reset the EQ or is there a way to completely "disengage" DSP completely?

I clicked on the button in the UI to set it to flat.

 

[amirm]

If so was the first FFT measurement done with as the Unit is turned on? with some EQ applied (not at 1K but still going trough a DSP algorithm.)

No all measurements were after I fixed the bass issue.

 

[sam_adams]

@amirm, it's good to see you test the good, the bad, and the ugly. In fact, I enjoy the livelier discussions about the bad reviews more than the ones about the good ones.

 

[restorer-john]

It sure is a strange set of results. Some good, some bad and a whole lot of headscratching.

 

[Toslink]

This is quite impressive! Low noise, impressive amount of power, and great functionality.

Does it support volume control via a remote? How does the input matrix work? it says one input at a time.

It supports volume control from either IP commands or IR control from the rear-panel input jack. I should "out" myself as the owner of this amplifier.

 

[Dave Tremblay]

Did you happen to run an FFT with no input signal? I’m wondering if that noise is constant, and related to the DSP in there.

 

[amirm]

Did you happen to run an FFT with no input signal? I’m wondering if that noise is constant, and related to the DSP in there.

I did not and the thing is packed ready to be shipped unfortunately. It is a good suggestion though.

 

[peniku8]

It's lovely and very well done. I like the bituminous mat to damp the case too.

The only thing is the lack of twisting on the speaker out cable pairs.

Thanks! What's the point of twisting the speaker cables when I zip-tie them together? Better channel identification? Cleaner look? Lower inductivity (lol)?
And yes, the mats give it a nice feel of quality, with the added weight and the damped case! It's still pretty light, even with the mats, as one would imagine using class D amps.

 

[David_M]

Amir mentioned crosstalk is nothing to complain about, but at -60 dB at 10k isn’t that dangerously close to audible? At high volume that could diminish soundstage, couldn’t it?

What? -60dB xtalk @10kHz being audible?

You should be aware that our beloved analog FM stereo radios that have been with us for decades and provided lots of enjoyable music over the ensuing decades have stereo separation figures of -35dB to -40dB (on strong signals) in the mid-range and worse at the extremes! And yet, we enjoyed the stereo effect very much. No complaints from customers whatsoever.

Why didn't it sound like mono with such 'poor' specs? Our ears mask a lot of musical content based on its loudness levels. The majority of music exists in the midrange and that's what is played the loudest. High-frequencies of 10kHz are 'masked out' or given 'less priority' by our brains, so they do not seem to contribute that much to imaging.

Having -120db xtalk @10kHz is really nice but your brain will not have a fit if it was @-60dB. This means that if the right channel is playing 1 Watt of music, the left channel experiences a 1uW of xtalk or interference from the right channel. You will not hear it as you are not superman with super hearing capabilities...and on top of that, your ear will be pre-occupied with 1W of music from the left channel itself.

So 1W of music in the left channel + 1uW from right channel xtalk ===> 1.000001W of combined music power, where 0.0001% comes from the crosstalk channel... You will not hear or not even be aware that it exists.

Human ears are NOT precision instruments like the APx measurement system. They are not designed that way. They are much blunter instruments than we'd like to believe.

 

[MediumRare]

What? -60dB xtalk @10kHz being audible?

You should be aware that our beloved analog FM stereo radios that have been with us for decades and provided lots of enjoyable music over the ensuing decades have stereo separation figures of -35dB to -40dB (on strong signals) in the mid-range and worse at the extremes! And yet, we enjoyed the stereo effect very much. No complaints from customers whatsoever.

Please forgive me but suggesting FM as some reference for acceptable audio quality is not persuasive. I'll take my lectures on psychoacoustics from published experts, thanks.

I chose 10 kHz as an example, overall the crosstalk is very poor. I also said "dangerously close to audible", not a glaring issue.

Yes, at high volumes (not 1 watt, try 20 watts and 200 watt peaks) -60db is audible. Try it at home. Amir suggests -115 dB as the threshold of audibility for some measures.

From the AP website itself:
"values of crosstalk of 60–70 dB and more are desirable" - sounds like a minimum standard, not a goal.

 

[Velocipede_Acoustics]

So get a miniDSP and a CrownXLS amp for less than half the cost. Got it.

 

[David_M]

Please forgive me but suggesting FM as some reference for acceptable audio quality is not persuasive. I'll take my lectures on psychoacoustics from published experts, thanks.

I chose 10 kHz as an example, overall the crosstalk is very poor. I also said "dangerously close to audible", not a glaring issue.

Yes, at high volumes (not 1 watt, try 20 watts and 200 watt peaks) -60db is audible. Try it at home. Amir suggests -115 dB as the threshold of audibility for some measures.

From the AP website itself:
"values of crosstalk of 60–70 dB and more are desirable" - sounds like a minimum standard, not a goal.

I believe you are making my point, probably without realizing it. The masking effect is even more prevalent at higher SPLs than at lower ones. The ear-brain system will be preoccupied processing higher SPLs while masking out the simultaneous but much lower-by a factor-of-a-million(!) xtalk sounds.

Yes, I used the FM stereo example as an extreme one to let one know that you do not NEED -100dB (or better) crosstalk figures to get the full stereo effect (HD FM radio is not much better). Desirable, yes, ofcourse! But psychoacoustically unnecessary. Naturally, I'd like to have the best technical specs possible for all my electronic devices, if not to make me feel better. That's why, for example, people here frown upon devices with, for example, a 0.01% THD while praising 0.001% (or better) spec'd devices as being far more transparent....yet they ignore the big sources of distortion in their systems ... their main speakers which have single-digit distortion specs or worse at increasing SPLs. A good subwoofer, for example, is said to be transparent to the ear if its distortion is under 10% at high SPLs, with 5% being a really excellent figure. My MartinLogan electrostatics measure at 0.1% in the midrange and this is a superb figure...by speaker standards, that is.

AP's target of 60-70dB is an engineering target for the devices their measure, not one based on psychoacoustics. As an EE myself with 20+ years of low-speed but ultra-quiet designs and high-speed (10+ Gbps) circuit design experience as well, I'd prefer to set a goal of -100dB crosstalk or better across the full audio bandwidth, not because my ear can hear it if it's less, but because it lets me know I designed my product extremely well with careful PCB stack and layout, judicious use of targeted shielding, proper selection of capacitor values, etc. Pride and bragging rights instincts are strong amongst engineers. Besides, marketing would be screaming at me when they insist I have to exceed our competitors -100dB xtalk figures, with -110dB or better...a numbers game with these people. They'd categorically reject a -60dB xtalk design as being utterly 'terrible' and not competitive, despite it being audibly innocuous. Guess who wins this battle?

Have you looked at full bandwidth xtalk specs of typical 7-channel multi-channel power amps (e.g 200W/Ch typical), all sharing one power supply with their individual power cards crammed next to each other into one chassis like sardines? Maybe you shouldn't coz you won't like their xtalk specs at full power .

 

[MediumRare]

I believe you are making my point, probably without realizing it. The masking effect is even more prevalent at higher SPLs than at lower ones. The ear-brain system will be preoccupied processing higher SPLs while masking out the simultaneous but much lower-by a factor-of-a-million(!) xtalk sounds.

Have you looked at full bandwidth xtalk specs of typical 7-channel multi-channel power amps (e.g 200W/Ch typical), all sharing one power supply with their individual power cards crammed next to each other into one chassis like sardines? Maybe you shouldn't coz you won't like their xtalk specs at full power .

1. No I did not make your point, re loudness. I am talking about the different experience between 80 dB SPL and Amir’s 96 dB listening, with dynamics peaks beyond that.
2. We are discussing crosstalk, the primary effect of which is stable left/right soundstage. Example: does the shimmer of a cymbal move after the cymbal strike. With extremely poor crosstalk it would.
3. Check your math, my friend. -60 dB is .1%, that’s 2 orders of magnitude different from what you referenced. You try playing a 0 dB tone panned in the left speaker and a -60 in the right and tell me if the soundstage changes. It will, 100%.
4. FM is awful. We thought AM and vinyl was good when that was all we had. Listen to HD radio and you can’t go back. Listen to proper red book and HD radio does not suffice in a primary/critical listening system.
5. I am a 2.1 channel listener; AVs, aside from their specs, cannot deliver the current spikes needed for proper dynamics even with only two speakers.

 

[David_M]

1. No I did not make your point, re loudness. I am talking about the different experience between 80 dB SPL and Amir’s 96 dB listening, with dynamics peaks beyond that.
2. We are discussing crosstalk, the primary effect of which is stable left/right soundstage. Example: does the shimmer of a cymbal move after the cymbal strike. With extremely poor crosstalk it would.
3. Check your math, my friend. -60 dB is .1%, that’s 2 orders of magnitude different from what you referenced. You try playing a 0 dB tone panned in the left speaker and a -60 in the right and tell me if the soundstage changes. It will, 100%.
4. FM is awful. We thought AM and vinyl was good when that was all we had. Listen to HD radio and you can’t go back. Listen to proper red book and HD radio does not suffice in a primary/critical listening system.
5. I am a 2.1 channel listener; AVs, aside from their specs, cannot deliver the current spikes needed for proper dynamics even with only two speakers.

Fair enough ... but regarding the -60dB figure, my calculations were referenced in power (watts) since that's what all amplifiers produce.

10 * log (10^-6) = -60dB...that was my comparison between 1W of output combined with 1uW of crosstalk or 1kW of output combined with 1mW of crosstalk. The ratio between these numbers (1uW/1W or 1mW/1kW), in dB referenced to watts, is -60dB.

The 0.1% figure you gave is referenced to voltage, where 20 * log(0.1%)= -60dB.

If you think you can tell apart the influence of a 1mW crosstalk signal mixed in simultaneously with a 1,000 Watt main signal, then peace! All power to you, my friend...

 

[MediumRare]

Fair enough ... but regarding the -60dB figure, my calculations were referenced in power (watts) since that's what all amplifiers produce.

10 * log (10^-6) = -60dB...that was my comparison between 1W of output combined with 1uW of crosstalk or 1kW of output combined with 1mW of crosstalk. The ratio between these numbers (1uW/1W or 1mW/1kW), in dB referenced to watts, is -60dB.

The 0.1% figure you gave is referenced to voltage, where 20 * log(0.1%)= -60dB.

If you think you can tell apart the influence of a 1mW crosstalk signal mixed in simultaneously with a 1,000 Watt main signal, then peace! All power to you, my friend...

@amirm, can you please explain, when you report -60db Crosstalk, is that 0.1% or 0.001%? I.e., is it the same as playing a 0 dB signal panned in one channel and the same signal at -60dB panned in the other channel?

 

[LTig]

What? -60dB xtalk @10kHz being audible?

You should be aware that our beloved analog FM stereo radios that have been with us for decades and provided lots of enjoyable music over the ensuing decades have stereo separation figures of -35dB to -40dB (on strong signals) in the mid-range and worse at the extremes! And yet, we enjoyed the stereo effect very much. No complaints from customers whatsoever.

Yep, and vinyl is even worse, rather -25 to -35 dB maximum. Still the lovers often state better sound stages than digital.

 

[amirm]

Thanks! What's the point of twisting the speaker cables when I zip-tie them together?

Better rejection of interference picked up from the rest of the amp.

 

[amirm]

@amirm, can you please explain, when you report -60db Crosstalk, is that 0.1% or 0.001%? I.e., is it the same as playing a 0 dB signal panned in one channel and the same signal at -60dB panned in the other channel?

I don't understand your statement. The test plays a tone at X level in one channel, and measures what ratio bleeds into the other. The level is specified by me. For amps, I pick the level that generates 5 watts although using other levels doesn't make that much difference (until you run into noise issues).

The test is much more severe than real life in that it is full amplitude at higher frequencies. In reality your music level drops way down at higher frequencies. If the highs are 40 dB down from bass and crosstalk is 60 dB, then the interference in the other channel is at -100 dB. This is why I don't get bent out of shape over crosstalk measurements unless they are really poor. Is this what you were saying in your post?

 

[MediumRare]

I don't understand your statement. The test plays a tone at X level in one channel, and measures what ratio bleeds into the other. The level is specified by me. For amps, I pick the level that generates 5 watts although using other levels doesn't make that much difference (until you run into noise issues).

The test is much more severe than real life in that it is full amplitude at higher frequencies. In reality your music level drops way down at higher frequencies. If the highs are 40 dB down from bass and crosstalk is 60 dB, then the interference in the other channel is at -100 dB. This is why I don't get bent out of shape over crosstalk measurements unless they are really poor. Is this what you were saying in your post?

Yes, exactly. I’ve looked for papers on audibility of crosstalk but haven’t found much. My hypothesis is we are quite sensitive as placement of sources across a soundstage is very stable above a few hundred Hz even for sounds at a level quite below the overall signal. For me, this is the magic of a really transparent system and a great recording. Crosstalk in electronics would only - I imagine - reduce the width of a soundstage for a given recording. Do you know of any test recordings/warbles etc. that can demonstrate sensitivity to this or accuracy of a system?