Review and Measurements and miniDSP 2x4 HD DSP and DAC

[Willem]

I use the 2x4HD to equalize my three subs with filters generated by MSO. For that it is fine. I would not want to use it to equalize at higher frequencies when its imperfections would potentially be audible, and for the main speakers I only have one channel left on the 2x4HD (and none if I decide to add a fourth subwoofer). I have an RME ADI-2 DAC, and I am planning to use its filters to equalize the range 80-300 Hz, but I am not yet sure what would be the best way to do that.

 

[Deleted member 48726]

I use the 2x4HD to equalize my three subs with filters generated by MSO. For that it is fine. I would not want to use it to equalize at higher frequencies when its imperfections would potentially be audible,

You worry in vain. Try it. You might be surprised.

I use it with a high gain amp. and I can't hear any noise a foot from the speaker. And within a foot the barely audible hiss is from the amplifier itself not the miniDSP.

 

[Willem]

You worry in vain. Try it. You might be surprised.

Thanks, this is reassuring. However, I still have the problem that the 2x4HD has only four channels of which I already use three, and will perhaps use the last one for a fourth sub.

 

[marX]

Is the unit undergoing revisions or the same as Amir's review unit?

Many companies keep releasing updated versions with more performance and bug fixes.
Just wondering what's the case here.

 

[Deleted member 48726]

Is the unit undergoing revisions or the same as Amir's review unit?

Many companies keep releasing updated versions with more performance and bug fixes.
Just wondering what's the case here.

There are firmware updates. I think I've seen changelogs on their site.

 

[marX]

There are firmware updates. I think I've seen changelogs on their site.

Thanks. So, only software updates, right?

 

[TurtlePaul]

Thanks. So, only software updates, right?

Will the unit undergoing updates not be a TI version (Amir tested a good pre-fire AKM).

 

[marX]

Will the unit undergoing updates not be a TI version (Amir tested a good pre-fire AKM).

So there are hardware differences between the current and older units?

 

[TurtlePaul]

So there are hardware differences between the current and older units?

Yes, about three years ago there waa a fire at the AKM seniconductor fab. Like a lot of products, the AKM chip in the 2x4 HD was then replaced with TI chips in the new revision. This TI version is about 3 dB better SINAD.

 

[ah-ra]

Just a small update: I received the upgraded 2x4HD from Sweetspot Audio last week and it is now on its way to Amir. I hope it will arrive safely...

I had an 2x4HD and a DDRC24 modified by Sweetspot Audio. In my opinion it brought a significant improvement to the sound overall. Any updates when your unit will be tested? I'm very much looking forward to the review....

 

[baron-bob]

I had an 2x4HD and a DDRC24 modified by Sweetspot Audio. In my opinion it brought a significant improvement to the sound overall. Any updates when your unit will be tested? I'm very much looking forward to the review....

Hi,
that's interesting to hear. I did not had the opportunity to test the upgrade by my self so far because I send it straight to Amir after I got it back from Sweetspot. The modified dsp arrived two weeks ago at Amir's place. I did not got a reply from him since then, so I'm not sure when it will be measured...

 

[TurtlePaul]

I mean, this is a little silly and I need to call it out because we are on ASR. You are claiming you could hear a difference between when you sent a unit for upgrade and when you got it back weeks later? Expectations bias?

 

[Purité Audio]

Modifications ‘always’ improve the product it is common knowledge!
I had a client who amongst other ‘upgrades’ had a new clock added to his cdp after a few weeks the front panel display failed he sent it back to the manufacturer.
They examined the unit and told him that the new clock had been wired to the front panel display hence the failure, when he asked about the other modifications ( he had been shown a cup full of the old replaced components) they told him there were none!
Keith

 

[ah-ra]

I mean, this is a little silly and I need to call it out because we are on ASR. You are claiming you could hear a difference between when you sent a unit for upgrade and when you got it back weeks later? Expectations bias?

I think you are referring to my post. In general I would agree, but I have two units (the DDRC24 is basically a 2x4HD), so I could compare and I can say the mod made a difference to me, so I also had the other one modified. It's not night and day of course, but noticable. I'm not a technician, but I assume this is mostly due to better OP amps.
I also had a long conversation with the owner of Sweetspot Audio and he would have refunded me, if I would not have been satisfied.

 

[ahofer]

I think you are referring to my post. In general I would agree, but I have two units (the DDRC24 is basically a 2x4HD), so I could compare and I can say the mod made a difference to me, so I also had the other one modified. It's not night and day of course, but noticable. I'm not a technician, but I assume this is mostly due to better OP amps.
I also had a long conversation with the owner of Sweetspot Audio and he would have refunded me, if I would not have been satisfied.

It's great that you are satisfied. But it would be truly surprising to many of us if the difference here were audible. Are you sure you level-matched your comparison? Did you know which one was playing? These things tend to melt away under controlled conditions.

And if they don't? Then you should send the two units in for measurement so we can spread the good word. I'm sure sweetspot would be thrilled.

 

[ah-ra]

It's great that you are satisfied. But it would be truly surprising to many of us if the difference here were audible. Are you sure you level-matched your comparison? Did you know which one was playing? These things tend to melt away under controlled conditions.

And if they don't? Then you should send the two units in for measurement so we can spread the good word. I'm sure sweetspot would be thrilled.

There's already a modified unit waiting for review, so let's wait....

 

[Kayshot]

I've finally run time-alignment using the 2x4 HD and wow, what a difference!
I do have one issue I'm hoping for some guidance on though.

-I added a manual house curve to my subs in REW
-I dragged the curtain all the way to the left (20hz) in Audyssey before re-running room correction.

Problem is, when I turn on Dynamic EQ in Audyssey now, the subs are just way too loud. I could of course cut the trim, but I feel like that might not be ideal.

I found a few people stating you should not add a manual house curve in REW if you plan on using Dynamic EQ, rather I should EQ for flat response, then let Audyssey add the house curve thru Dynamic EQ.

Questions:

1.) Is this correct?
2.) Would I want to leave the curtain in XT32 at the far right for the sub if I do take this route?
3.) If EQ'ing for a flat response in REW, do I want to remove the curve I created in REW entirely and just EQ within the PEQ editor in the MiniDSP software?
Or do I still want to use that filter in REW, but set the blue line straight instead of the house curve, getting the response to hug that flat line, then also go on to flatten it out more with PEQ in the MiniDSP software?

 

[tjcinnamon]

I've finally run time-alignment using the 2x4 HD and wow, what a difference!
I do have one issue I'm hoping for some guidance on though.

-I added a manual house curve to my subs in REW
-I dragged the curtain all the way to the left (20hz) in Audyssey before re-running room correction.

Problem is, when I turn on Dynamic EQ in Audyssey now, the subs are just way too loud. I could of course cut the trim, but I feel like that might not be ideal.

I found a few people stating you should not add a manual house curve in REW if you plan on using Dynamic EQ, rather I should EQ for flat response, then let Audyssey add the house curve thru Dynamic EQ.

Questions:

1.) Is this correct?
2.) Would I want to leave the curtain in XT32 at the far right for the sub if I do take this route?
3.) If EQ'ing for a flat response in REW, do I want to remove the curve I created in REW entirely and just EQ within the PEQ editor in the MiniDSP software?
Or do I still want to use that filter in REW, but set the blue line straight instead of the house curve, getting the response to hug that flat line, then also go on to flatten it out more with PEQ in the MiniDSP software?

I dial it to taste. Luckily I listen to it at pretty consistent volumes. So I calibrate with DEQ on.

For the curtain, going past the XO is preferred, so you’re good there.

I recommend EQ’ing with the miniDSP after xt32

 

[Chromatischism]

I've finally run time-alignment using the 2x4 HD and wow, what a difference!
I do have one issue I'm hoping for some guidance on though.

-I added a manual house curve to my subs in REW
-I dragged the curtain all the way to the left (20hz) in Audyssey before re-running room correction.

Problem is, when I turn on Dynamic EQ in Audyssey now, the subs are just way too loud. I could of course cut the trim, but I feel like that might not be ideal.

This is an incorrect use of DEQ because it is normally starting from a flat baseline. Final bass levels need to be tuned with DEQ already on. If you can change the order of your process, it would probably fix that.

 

[Old_School_Brad]

I’ve been using a DDRC-24 for many years alongside a high-gain amplifier. It does produce a faint hiss from the tweeters, which becomes inaudible at a distance of about 30 cm. from the tweeter. In the thread, I came across someone who reduced the noise by replacing the power brick. I’m considering trying that out, purely as an experiment.