Anyone tried a mini DSP?

[sibelius7]

Further to a recent post about wanting to sort out my room mode issues, I stumbled across this https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4-hd

Anyone have any experience with such devices?

 

[abacus]

One of the most popular reasonably priced DSP units out there, (And not just for the niche Hi-Fi/AV market) but it can be a pig to setup, (Unless you have decent knowledge of DSP operation) just make sure you get the calibrated microphone as well a fully reading the setup instructions first.

Bill

 

[andyjm]

These guys (based in HK) have being doing some of the most innovative stuff in HiFi over the last few years.

While half the community in the UK are stroking their respective beards, drooling over 'single ended triodes' and arguing about what grease to use on their tonearms, miniDSP have been really pushing back the frontiers of what is available for a home user.

Back in the day, these guys would have been based in the UK, probably a bunch of smart guys straight out of university. Now they are in HK. Sign of times I am afraid.

Back to the OPs question, their stuff is great. Earlier modules were unboxed circuit boards and needed a pretty good understanding of filter design and DSP, but the more recent models are much more user friendly and plug'n play. Highly flexible, and excellent support. Their forum is also excellent, with very active participation of users - so if you want specific feedback on a particular model have a look on there.

 

[insider9]

I've used 2x4 HD and OpenDRC DA8 if they fully meet your needs both fantastic units. I can easily say UMIK-1 is one of the best purchases I ever made.

One thing I will add. If you really want to sort out your room buy a UMIK-1 and try acoustic room treatment first. Only then add Minidsp. DSP however important has limitations and if I only could do one it would be the acoustic room treatment.

 

[paulkebab]

at one of these too, as I'm pretty sure I also have a timing issue in the midrange. There might be other problems but this is the stand out one in my room. Am I correct in thinking that all frequencies can be phase shifted? That's how it looks in the specs, if that's the case I'll be getting one soon.

 

[insider9]

Yes, Paul 2x4 HD can adjust phase.

 

[paulkebab]

that's what I thought. Another question is whether to go for optical source/DSP/optical out/DAC/amp or optical source/DAC/optical out/DSP/amp. I think they can supply either one, their tech guru is out today but should reply tomorrow or Friday.

EDIT or more simply DSP before or after DAC?

 

[insider9]

That's entirely up to you they make many devices and lots for DIY enthusiasts. You can do just about anything analogue to analogue, digital to analogue or digital to digital. Really depends on your needs. To fit into your setup instead of your Behringer I'd look at OpenDRC - DI.

 

[paulkebab]

exactly what I want, every search I tried pointed me to other units. The Behringer does have a timing adjustment but it's not frequency specific. Thanks for the info insider, much appreciated.

 

[insider9]

Glad it helps. If you were to get one I'd suggest buying directly from Minidsp. Cheaper than anywhere else even including import duty and taxes, quick delivery and very good service and support.

 

[paulkebab]

the prices are very keen. Just as a precursor I'm going to have a session with REW just to make sure it's definitely a timing issue. I can almost get around it with the Behringer but the lost detail makes it a bit of a 'close but no cigar' situation.

 

[sibelius7]

So you think room treatment is going to make the biggest difference regarding room modes?

 

[insider9]

If you're trying to lower the peaks then DSP will do just fine. You will not fix a nil with any amount of DSP.

Best advice is to work on speaker positioning and listening position first. That makes a massive difference and often is underestimated. If we're talking deep bass then bass traps will be huge and you have to be realistic on both size and cost. If it's mid or upper bass then a mix of acoustic room treatment and DSP would work best.

I'm only talking from experience. Treating my listening room was the biggest sonic upgrade I ever did. Best part is any system I now put in there sounds to its fullest potential. I didn't actually focus on bass but reflections and reverberation. Bass improved as a result but I don't actually use any bass traps.

I'm a big fan of DSP but make sure you know what can and can't be done with it as you will avoid disappointement. DSP is heavily limited in what it offers, however the things it does well are brilliant and can't be done with room treatment.

 

[sibelius7]

Quick update - i bought a minidsp HD 2x4 in the end. I've had it for a couple of months, and i must say it's stunning.

I programmed it using data from REW room measurements - then went through the process of realising a perfectly flat frequency response isn't what i actual want (read many articles about this). Have a lovely taylored freq response now.

Anyway - its absolutely solved the main issue i was trying to address which was the room mode. To give you a feel for the problem, i have to run -19db at 48hz to even out the bottom end! I think i would have had to have a room entirely filled with bass traps to fix that any other way...

 

[gasolin]

https://www.youtube.com/watch?v=E4OY0MhMKTc

 

[insider9]

I programmed it using data from REW room measurements - then went through the process of realising a perfectly flat frequency response isn't what i actual want (read many articles about this). Have a lovely taylored freq response now.

Hahaha, I'm glad I'm not the only one who's done this 🙂

Have you used rePhase yet to create FIR filters? Or are you using FIR but using different software?

 

[batonwielder]

Quick update - i bought a minidsp HD 2x4 in the end. I've had it for a couple of months, and i must say it's stunning.

I programmed it using data from REW room measurements - then went through the process of realising a perfectly flat frequency response isn't what i actual want (read many articles about this). Have a lovely taylored freq response now.

Anyway - its absolutely solved the main issue i was trying to address which was the room mode. To give you a feel for the problem, i have to run -19db at 48hz to even out the bottom end! I think i would have had to have a room entirely filled with bass traps to fix that any other way...

So does this mean we don't need to buy expensive speakers anymore? *dash1*

 

[paulkebab]

that's a big mode, I thought I had trouble with a +8dB @ 200Hz. After taming that I'm not sure whether to go with miniDSP as things sound really good now.

 

[newlash09]

I programmed it using data from REW room measurements - then went through the process of realising a perfectly flat frequency response isn't what i actual want (read many articles about this). Have a lovely taylored freq response now.

Hahaha, I'm glad I'm not the only one who's done this 🙂

Have you used rePhase yet to create FIR filters? Or are you using FIR but using different software?

I was under the impression that minidsp had FIR filter options and running rephase on windows was not necessary. Is this wrong.

By the way, since you are presently using roon for DSP, and have experience with minidsp offerings, do you think one is superior to the other as far as room correction goes. If roon can do everything that minidsp does, it will be one box less on the rack 🙂

But I do understand that minidsp has more flexibility in that a lot of digital sources can be fed through it , where as roon is limited to tracks played via tidal and nas.. Thanks

 

[insider9]

Yes, you can use FIR in Minidsp some products that includes 2x4 HD. However you need to design filters in another software. Hence my question about rePhase. rePhase is free to use and one of many programmes you could use to do it. There are some interesting paid solutions that help as are not fully manual and offer a little more however cost can be high.

As to differences between Roon DSP and Minidsp. From memory 2x4 HD can used 9,600 taps in total (length of filter). That's 4,800 per channel. OpenDRC DA-8 had more but not by much (around 12,000 total if I remember it right). If you're considering correction in bass using FIR such filters will not do much as they're just too short. So most likely you will correct bass with parametric EQ and mids, treble and phase with FIR. Also you're forced to use specific sampling rate with 2x4 HD it's 96kHz. That means anything sent to Minidsp will be resampled to 96kHz. That's not ideal.

In rePhase which I'm using I can design filters that are 131,000 taps long. That's 131,000 taps per channel. Also I can create them in various sampling rates. You then put all the filters in a zip archive and Roon selects filter with appropriate sampling rate automatically depending on track being played.

With Minidsp I couldn't design FIR filters that were good enough as the units just lacked processing power. Roon has power to spare. This is not to say I discourage use of Minidsp as I rate their products. However it's worth knowing what the limitations are.

 

[newlash09]

Yes, you can use FIR in Minidsp some products that includes 2x4 HD. However you need to design filters in another software. Hence my question about rePhase. rePhase is free to use and one of many programmes you could use to do it. There are some interesting paid solutions that help as are not fully manual and offer a little more however cost can be high.

As to differences between Roon DSP and Minidsp. From memory 2x4 HD can used 9,600 taps in total (length of filter). That's 4,800 per channel. OpenDRC DA-8 had more but not by much (around 12,000 total if I remember it right). If you're considering correction in bass using FIR such filters will not do much as they're just too short. So most likely you will correct bass with parametric EQ and mids, treble and phase with FIR. Also you're forced to use specific sampling rate with 2x4 HD it's 96kHz. That means anything sent to Minidsp will be resampled to 96kHz. That's not ideal.

In rePhase which I'm using I can design filters that are 131,000 taps long. That's 131,000 taps per channel. Also I can create them in various sampling rates. You then put all the filters in a zip archive and Roon selects filter with appropriate sampling rate automatically depending on track being played.

With Minidsp I couldn't design FIR filters that were good enough as the units just lacked processing power. Roon has power to spare. This is not to say I discourage use of Minidsp as I rate their products. However it's worth knowing what the limitations are.

That knocks the minidsp out of contention then. I was also considering the ddrc-22d with Dirac live. But not sure anymore. My avr has audeyssey eq which though good for movies, feels a little lifeless for music when compared to the 2 channel system. And I think dirac is also a very automated correction system like the audyssey. So I want more control over the RC intervention. Roon seems to trump here too. And the cost of the ddrc-22d will net me a lifetime roon license too, with change to spare. Thanks again...you're suggestions have always been very helpful 🙂

 

[insider9]

Happy that it helps.

But do bear in mind that for all the great features at present Roon can only play local files, Tidal and Internet radio. It won't do DSP or play anything else. I know guys at Roon are looking in to add more sources but if and when they do no one knows.

However if that's good enough for you and you run it on good enough equipment you will be rewarded with DSP on every zone you set it on. That's where I think Roon is a great value solution. As it would cost you multiple Minidsp or Dirac Live licences for playback on many devices. Roon handles it all. And if you don't have multiple zones maybe you sometimes listen via headphones from your mobile. These can also be corrected 🙂