DSP box for room correction, maybe also ‘loudness’ correction

Whilst treatment of rooms is the acoustically ideal way to improve/optimise the final part of a music replay system, and the only way to fix some issues like cancellations or near reflections, DSP can also be a valid tool, particularly in a domestic environment where physical treatment may not be practicable. DSP used for room correction has the added advantage of evening out frequency unevenness caused by any part of the system, not the room in isolation.

It has been said that DSP causes audible artefacts, but in my view it is a matter of balancing those artefacts against the distortions of sound caused by the room, in many or even most cases I suspect the latter may be more significant.

I know some forum members use or have used the facility within Roon to apply convolution filters for room correction, reporting satisfaction with the outcome. The processing in that case is within the computer running Roon (‘Roon Core’ IIRC).

I also know some forum members have used Dirac Live, with a number reporting beneficial effect, though I don’t know what boxes have been used to do this.

Audirvana allows, or did allow, Dirac as a ‘plug in’, and when first facilitated I tried it, running on my Mac Mini, though was unconvinced at the time, and that would tie me to Audirvana, whereas I don’t see that remaining in the long term.

In my active driving of speakers, my digital XO had spare DSP capacity, which I used to good effect to even out some of the worst peaks in my room, with two settings to accommodate two different speaker positionings (one optimal, the other not but fitting with other room use). Compensation was determined manually using REW to analyse.

The thread title mentions “loudness” correction - compensating for reduced ear sensitivity to frequency extremes, particularly bass, at low listening levels. I have written about this before in other threads - it occurs to me the if a DSP box allows selection of more than one room correction filter, a second (or more) could be prepared with target curves compensating for the difference in ear sensitivity at a lower level compared to whatever level is used for the standard room correction.

Having just changed speakers I am now not driving actively, but would like to continue to benefit from DSP room correction. I could potentially continue using my active XO box (modified Behringer DCX2496) setting up as single driver with no crossover): But that comes after my DAC and I think it would be beneficial to shift the DSP to the digital path before my DAC, removing the extra ADC-DAC from the signal path.

So I’m into the idea of a DSP box to put in the digital signal path before the DAC. No analogue output is needed. An analog input may have value - at present when I play analog sources (for music making) I swap my power amp input from DAC to a preamp, but instead they could benefit from the same room correction, provided that latency isn’t too great.

MiniDSP do a box that on paper sounds possibly suitable, their SHD Studio. Apparently it can run Dirac, or use REW created filters, or can be programmed by the user. However, despite inputs accepting up to 288KHz sample rate internally it runs at 96, which would appear to be a possible limitation to higher res recordings - though whether any different audibly is another matter.

Has anyone else made use of a DSP box for such a purpose? If so what box, and what was your conclusion?

Views on other DSP room correction solutions are also most welcome.

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Hi IB, the Accuphase DG-68 has digital in/out and seems to have good reviews.

Thanks, Bigboy! (I’m not sure I like saying that!) However it is incredibly expensive, even secondhand - perhaps partly because it has an unnecessary DAC, and perhaps because it appears to be so very versatile

Call me BB …. These boxes are very interesting and you need a good one that doesn’t inject noise in the process. The DG-68 can also replace your DAC as you can have digital input and analogue output. I’d like to have one but it’s a bit too expensive at the moment. Maybe Naim will produce its own version one day.

Anyone else have any relevant experience or knowledge to contribute?

I use a DSP in my system…

However…

It only filters the drive to the sub. This leaves the more critical signal to the midrange unaffected by the DSP artefacts and yet neatly deals with issues caused by the room modes.

Yes, I was aware that you use a MiniDSP product for that. The limited frequency range using just for subs inherently limits negative effects, which is good, but as you recognise I’m considering the possibility of putting the full range signal through a DSP box.

Out of curiosity which of their products do you use?

I have used Trinov (studio and amethyst) in the past. Both very natural and I could not detect any downsides- apart from the fact it digitised my turntable. Ultimately this is why I do not use it any more.

They are not cheap but the studio, I think will go before your dac if you wish

I’m using the Space Optimisation offered by my Linn DSM. It works by modelling the room (you need to input a fair amount of spatial data) and only affects frequencies below 80Hz. For me, it simply made the music more realistic and the musicians more present. If there are any adverse artefacts, my hearing is not good enough to detect them.

I believe there are others on the forum who also use SO, although not all Linn owners are as enthusiastic, I understand.

Roger