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miniDSP 2x4 HD Sweetspot-audio Mod Review

Rate this DSP Mod:

  • 1. Poor (headless panther)

    Votes: 193 87.7%
  • 2. Not terrible (postman panther)

    Votes: 17 7.7%
  • 3. Fine (happy panther)

    Votes: 2 0.9%
  • 4. Great (golfing panther)

    Votes: 8 3.6%

  • Total voters
    220

baron-bob

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The thing is that one expects that companies like this will have a way to measure stuff which in that level of THD+N is trivial,it don't have to be a AP555 to see it,a simple decent interface or better a Cosmos ADC with REW or Multitone Analyzer can do it and show all that stuff in all it's glory.

It's really inexplicable.
Yeah, I really do not know how to confront Sweet-Spot Audio with this:oops: But I think I will to call him about it and perhaps he is willing to share his own measurements with us. I will give an update about it.
 

TheBatsEar

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What is lost in dynamic range at pre-out of the AVR that can not be recovered by DSP, or do I get something wrong?
Right, you are absolutely right.

Yeah, I really do not know how to confront Sweet-Spot Audio with this:oops:
Maybe don't? It's not your job to change his train of thought. Call him, tell him the review is up, and say thanks.

He wont be able to give you better measurement, since there aren't any. And he wont agree with the review because his business is at stake. We have seen what happens when you confront people with facts, with Danny from GR Research and with the dude from PS-Audio. It's not pretty, i wouldn't waste too much time on it.;)
 

ah-ra

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Hello fellow members,
oh boy how stupid and naive I must look to you right now :eek:


I must admit that I really trusted him after I talked to him about the mod and also because he made the upgrade for free and knew that I was going to send it in to Amir. I was really surprised when the measurements came in. I was not expecting very much but an decrease in performance would not have been my first bet....:(

One thing I want to mention is that Amir did not measured the analog to anlog performance. This would be nice to have because Sweet-Spot Audio said that the mod is aimed at this. I also want to use the 2x4 HD in this way so it would be great if Amir could do this before he is sending it back to me.

So far I never had a DSP integrated to my speakers, only with my subs. When I have my setup back running again in a month or so the first thing that I will try is to hear a difference between AVR > AMP and AVR>DSP>AMP. With no EQ or so just to check if I can hear any difference because of the ADC/DAC process. I guess that I will not be able to discern the two chains from each other but I'm curious how it will be. On Audioholics they mentioned that chasing SINAD is something with diminishing returns after 80db. Also the DSP by it self can not improve the incoming signal from the AVR. I think that leaves little room for any mod to bring any audible benefit for the 2x4 HD.

But the question is still if the mod makes an audible difference and how it might sound. Some people like Marantz more than Denon despite the fact Marantz measures worse.
I'm afraid to ask this question ;) but how many of you think that the electronic measurements can not fully tell us how something might actually sound? I found this test from Amir where he made this recordings when he tested a power cable very interesting. He could proof this way that the cable made no audible difference. Something like that would be also nice for comparisons between other gear I think.

Sorry, did I get that right? You got the modification for free and it was clear that the unit will be sent to Amir for testing?

If that's the case, this is a no go for me. It would at least have been fair to hear what Sweetspot Audio has to say to the results before publishing as this review might have quite an effect on the company's business, as you can see from the discussion here.

For me it's still unclear if the results of this tests are valid as long as it's unclear whether the original version tested by Amir years ago has the same board and design inside as the modified version.
 
Last edited:

ah-ra

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Right, you are absolutely right.


Maybe don't? It's not your job to change his train of thought. Call him, tell him the review is up, and say thanks.

He wont be able to give you better measurement, since there aren't any. And he wont agree with the review because his business is at stake. We have seen what happens when you confront people with facts, with Danny from GR Research and with the dude from PS-Audio. It's not pretty, i wouldn't waste too much time on it.;)
Really? I think it was highly unfair to publish these results, without prior verification with Sweetspot Audio. Obviously the owner of the unit didn't pay a penny for the mod, which I think makes quite a difference here, as it does not make it look like scam to me. Who would be that stupid...

Maybe the results are valid, which would indeed be a shame, but maybe not. As long as it's obviously unclear if the original version tested is the same model as the modified device one should be quite cautious.

Did @amirm even know the circumstances here?
 

baron-bob

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Sorry, did I get that right? You got the modification for free and it was clear that the unit will be sent to Amir for testing?
yes, you got that right. I do not know what the policy is here in that case but Amir already asked me about measurements from the company. I will get in contact with them this week. But I want to say, as silly as it seems, when I called that guy last August and talked with him about the 2x4 HD and his mod it was mostly a conversation between two audiophiles. He first offered me a money back guaranty in case I don't like it or hear no difference and then the free upgrade so that I can send it in here while my home cinema is under construction. He came up with that by himself. I only asked him if he would send in one unit by himself.

The unit tested is around 2 1/2 years old but only got the mod last September. I would guess it is the same version as the one originally tested.
 

ah-ra

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yes, you got that right....

The unit tested is around 2 1/2 years old but only got the mod last September. I would guess it is the same version as the one originally tested.
Okay, that's your guess, but we can't be sure about that.

On the other hand, why should he send you a modded unit (for free!) when he should have known that it will show worse results than the original...? Makes no sense to me... That's why I questioned the results. Maybe something else is off with this unit or maybe not....

Nevertheless I think in this case he should have been asked for his opinion on the actual measurements before (!) publishing.

Your "interesting read" might have a significant impact on a small business with a quite good reputation...
 

TheBatsEar

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Sorry, did I get that right? You got the modification for free and it was clear that the unit will be sent to Amir for testing?
If that's the case, this is a no go for me. It would at least have been fair to hear what Sweetspot Audio has to say to the results before publishing as this review might have quite an effect on the company's business, as you can see from the discussion here.
Sweetspot-Audio will has opportunity to make a statement once they are aware the review is up. They can create an account and join us in this thread, like any other manufacturer. Remeber when we become paranoid in the Fosi V3 thread and thought some parts where fake? The manufacturer stepped in and set the record straight. Many, not least myself, had to acknowledge our mistake.
If they have evidence that there is some kind of mistake on our side, we will hear them and act accordingly.

For me it's still unclear if the results of this tests are valid as long as it's unclear whether the original version tested by Amir years ago has the same board and design inside as the modified version.
I bought the unit years ago, and sold it to @baron-bob when i updated to a Flex. At the time V2 wasn't a thing. @amirm has a unit that is years old too. Except for the mods they are the same board, unless you know of some secret revisions.

I think it was highly unfair to publish these results, without prior verification with Sweetspot Audio. Obviously the owner of the unit didn't pay a penny for the mod, which I think makes quite a difference here
I don't see why. Sweetspot-Audio was confident their work would reflect positively in the measurements. That wasn't the case. Tough luck.

Does @amirm have an obligation to give manufacturers a veto for publication if the results aren't good? I don't think so.


I hope that clears things up, mate. There was no attempt to trap Sweetspot-Audio or something. Just in case Sweetspot-Audio should develop sour feelings: i'll pay for the mod and all costs. But i doubt this is what they are after.

It's more likely they doubt @amirm methods of measurement. Which, btw, is always a fair target, he is a grown man and can, should and must defend his handywork :cool:.

Okay, that's your guess, but we can't be sure about that.
I sent @baron-bob the receipt. I also have the credit card record for proof.

why should he send you a modded unit (for free!) when he should have known that it will show worse results than the original...?
He didn't, that's the neat part for the casual observer :D. They really thought their stuff was ace. But it wasn't.

Your "interesting read" might have a significant impact on a small business with a quite good reputation...
Sad.
Many such cases.
Solution: don't sell fake improvements to unsuspecting folk.

If i where them i would go on a soul search mission. I wouldn't sell any mods that measure worse than the genuine article and i would thank everyone that shows me the errors of my way.

oh-jew_o_1034705.jpg
Dude!
 

TheBatsEar

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TheBatsEar

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pogo

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Okay, that's your guess, but we can't be sure about that.
The H/W and F/W versions should generally be listed in such tests.
For example, if module inserts are installed (see NAD T758 MDC), this should also apply here.
 

Randolf

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Thanks a lot Amirm for this review (an so many others). I am using a DDRC-24 since 20 month to bring DiracLive, which I found to be a very big improvement for my setup, into my Stereo system. It is a second generation device with the TI PCM3168A instead of AKM AK4626AVQ which was used in earlier devices. Perhaps Amirm compaired an unmodified AKM AK4626AVQ and a modified TI PCM3168A device or it is as it seems to be that the modification worsened the performance. Personally I would have not expected much of difference at all.

I know for sure that residual noise floor of a DDRC-24 is significantly to high to run it directly into a high gain power amp with high sensitivity speakers attached, this result in clearly audible hiss. But running it at -10db master volume (to safely avoid Dirac clipping) into an amplifier works pretty good. My device also had a critical fault after 14 month which caused it to startup at 0db master volume after each powercycle. Also taken into account that you cannot see the master volume from outside and there is no physical volume control I would never ever use it to control the volume.

For me (and I guees others as well) the open question is if I can find another DiracLive device (other minidsp, AV Receiver, Stereo Receiver) which really brings me an audible improvement in my setup.

Today I figured out that one can grap the DSP output of the minidsp via USB and after I figured out how to measure it's (purely digital) performance with REW accurately I am pretty confident one can pass it via USB/PC to whatever SPDIF or DAC device you want (see https://www.minidsp.com/forum/hardware-support/22596-2x4hd-ddrc-24-flex-recording-input ). Perhaps this helps some of the DDRC-24 or 2x4HD owners to do some nice direct A/B blind comparison (minidisp digital out+high end dac vs. minidsp RCA out, both with identical DiracLive filter settings). Perhaps someone can even measure it end to end with an expensive Audioanalyser.

Best regards
Randolf
 

Sokel

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Thanks a lot Amirm for this review (an so many others). I am using a DDRC-24 since 20 month to bring DiracLive, which I found to be a very big improvement for my setup, into my Stereo system. It is a second generation device with the TI PCM3168A instead of AKM AK4626AVQ which was used in earlier devices. Perhaps Amirm compaired an unmodified AKM AK4626AVQ and a modified TI PCM3168A device or it is as it seems to be that the modification worsened the performance. Personally I would have not expected much of difference at all.

I know for sure that residual noise floor of a DDRC-24 is significantly to high to run it directly into a high gain power amp with high sensitivity speakers attached, this result in clearly audible hiss. But running it at -10db master volume (to safely avoid Dirac clipping) into an amplifier works pretty good. My device also had a critical fault after 14 month which caused it to startup at 0db master volume after each powercycle. Also taken into account that you cannot see the master volume from outside and there is no physical volume control I would never ever use it to control the volume.

For me (and I guees others as well) the open question is if I can find another DiracLive device (other minidsp, AV Receiver, Stereo Receiver) which really brings me an audible improvement in my setup.

Today I figured out that one can grap the DSP output of the minidsp via USB and after I figured out how to measure it's (purely digital) performance with REW accurately I am pretty confident one can pass it via USB/PC to whatever SPDIF or DAC device you want (see https://www.minidsp.com/forum/hardware-support/22596-2x4hd-ddrc-24-flex-recording-input ). Perhaps this helps some of the DDRC-24 or 2x4HD owners to do some nice direct A/B blind comparison (minidisp digital out+high end dac vs. minidsp RCA out, both with identical DiracLive filter settings). Perhaps someone can even measure it end to end with an expensive Audioanalyser.

Best regards
Randolf
The highlighted is a (rare but usual) horror story which a lot of people do not admit by the fear of not be able to sell their down the road gear and I think the few brave ones who report issues like that are a great help for the rest.

I'll say it once again for the rest,make sure that a protection scheme is down the road when using stuff that can default to 0db,it's not only about gear,gear come and goes,it's about damaged hearing by exposing the full force of a system in all it's glory.

(yep,once mote,let me be the paranoid one,even if I benefit a single person I'll be happy about it)
 

TheBatsEar

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Randolf

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i have a phono preamp on the analog input of a MiniDSP Flex. Does that mean i could rip records to the connected RPi? :oops:
Yes ripping from Mac or Windows using ocenaudio wave editor is described here: https://www.minidsp.com/applications/advanced-tools/analog-recording-with-minidsp-adc . Basically clear and activate one filter preset / disable Dirac, crank up the volume to 0 db and use your favorite wave editor to rip the DSP output. Probably you can also do that from a RPi (at least streaming from the RPi to minidsp is described here https://www.minidsp.com/applications/audio-streaming/raspberry-pi-streaming. BUT WATCH OUT: If your mindsp directly drives a power amp you should disconnect it from the power amp while doing so since you have to crank up the mindsp master volume to 0db.
 
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TheBatsEar

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I have neither mac nor windows and i don't know what ocenaudio is. :facepalm:

My streamer is a RPi Zero2. I have arecord and so far it does something, but i don't know yet which device is the right one to record, once i'm home i'll put on a record and then i'll find out which device of the 5 possible i have to choose.

The only problem i see is that i can't set the sample rate to 96kHz and it's always recording as 32 bit. If i pick something else i get an error.
But this is maybe some Rasbian or Moode problem.

So far it records on these devices:

Bash:
#!/bin/bash

# arecord -L
devices="dsnoop:CARD=Flex,DEV=0 front:CARD=Flex,DEV=0 sysdefault:CARD=Flex plughw:CARD=Flex,DEV=0 hw:CARD=Flex,DEV=0"

for device in $devices ; do
  arecord \
    --format S32_LE \
    --rate=44100 \
    --channels=4 \
    --duration=60 \
    --device=$device \
    $(echo $device | sed 's/:.*//').wav
done
 

DrCWO

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I have neither mac nor windows and i don't know what ocenaudio is. :facepalm:

My streamer is a RPi Zero2. I have arecord and so far it does something, but i don't know yet which device is the right one to record, once i'm home i'll put on a record and then i'll find out which device of the 5 possible i have to choose.

The only problem i see is that i can't set the sample rate to 96kHz and it's always recording as 32 bit. If i pick something else i get an error.
But this is maybe some Rasbian or Moode problem.

So far it records on these devices:

Bash:
#!/bin/bash

# arecord -L
devices="dsnoop:CARD=Flex,DEV=0 front:CARD=Flex,DEV=0 sysdefault:CARD=Flex plughw:CARD=Flex,DEV=0 hw:CARD=Flex,DEV=0"

for device in $devices ; do
  arecord \
    --format S32_LE \
    --rate=44100 \
    --channels=4 \
    --duration=60 \
    --device=$device \
    $(echo $device | sed 's/:.*//').wav
done
You should record from the hw device. This is the direct hardware input without any preprocessing by ALSA. This is also the interface I use for rooPlay in my rooExtend suite.
Recording in 32 bit is no issue. You can convert it with SoX either in a pipe or from file later.
Best DrCWO
 

baron-bob

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I contacted Sweetspot yesterday and already got a reply. I have to agree with Ah-ra that it would have been better to get a statement from him bevor publishing the review. It can indeed have a negativ impact on his business and therefore deserves a fair chance. He also wrote that he values all the hart and work Amir put's in to this site even dough he is no member.

@amirm He would like to know/verify the following things:
1. are both DSP the same model? @amirm if you want to verify, I have no problem if you open my device to look at the PCB

2. have both DSP's been in the same configuration/reset? Apparently having a blank setting or one with any configuration has an impact on performance @amirm since I bought the unit used and never had it in use by myself it could be some EQ or so in the settings

3. where both measurements taken at the same day with the same device (the Audio Precision)?

4. was the identical power supply used for both devices/measurements?

He also send a vanilla and mod version yesterday to Gecom Technologies to have them measured independently from a second entity. I will also give him my unit for verification of measurements after it is back here in Germany.

I should have been more careful with some of my comments and will revoke/edit them accordingly until everything is on the table. Perhaps some other members want to do the same. I will keep you all informed.
 
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