DRC, high-passing main speakers, and two subs...which way forward?

[LewinskiH01]

Hello.

 

This post is to seek advice from experienced users. I've been reading up, but can't figure out the best way forward.

 

My system uses just a server as source. The system configuration is below, with my signature. I'd like to implement DRC, and I'd like to crossover the main speakers so they (and the amp) don't need to reproduce the low end, likely below 100 Hz or so, and send those frequencies to a pair of subs. From my readings I find a few ways to get this done, but all seem to have compromises.

 

A) One option is to implement a DRC software at the server, such as Dirac, and simply add an analog crossover between pre and amp, such as a Marchand or even a miniDSP that would do ADC and DAC. This is nice because of simplicity, but I believe such a setup would make it impossible for the DRC software to adjust the subs in the time domain, which seems would be a significant issue.

 

B) Another alternative would be to run the DRC software at the server and use a digital crossover, such as a miniDSP nanoDIGI. Actually this is what miniDSP recommended...but then I would need to buy a second DAC to drive the subs...and what should I do about the preamp? Likely ditch it and use a digital volume control. Convoluted, and not too appealing in terms of how it feels it would sound...at the end of the day, I still use my preamp because I like it better than driving the amp from the DAC...

 

C) Yet another option would be to replace my DAC and preamp with a DRC-enabled digital processor, such as a Lyngdorf DPA-1. Simple setup. I do wonder, though, about the transparency of this unit as a preamp vs my Lamm pre. And then a hard-wired DRC seems less upgradable than a software based solution, especially when I'm coming from a computer. It is appealing, though.

 

Am I making sense? Maybe I'm missing something altogether?

 

Would definitely appreciate guidance from experienced users!

 

Thanks in advance!!

[dallasjustice]

I use a DEQX HDP-4. It's very transparent. I replaced a $30,000 DAC with it so that should say something.

 

The best way to use a pair of subs is to run them both on mono. If you do that, you'll not want to crossover at such a high frequency if you can help it. At about 50hz you really can't locate LF. Above that there's still some localization.

 

DIRAC is not a crossover so you'll need one after the computer. That's what I do. If you don't want to do that, you could try audiolense or acourate with a MCH DAC like the exasound or lynx hilo. Ive heard the exasound MCH DAC. It's a fabulous performer for sure.

 

You'll also need delay. There's no "easy button" for delay, IME. You'll need to get familiar with REW and use it to get the delay and phase right. This isn't easy and I required help with it. If you want to do that part yourself, I'd suggest spending some quality time at hometheatershack.com. There's lots of folks there that can help with REW and sub woofer integration.

[LewinskiH01]

That was a quick reply!

 

How do you use your HDP-4? As DRC and digital processor only, or also as DAC/preamp? Why did you choose this unit? Not challenging, of course, but rather understanding the drivers behind the decision. Replacing a $30k DAC is certainly something!

 

So you are using Dirac on the computer, and later crossover at the HDP-4, correct? Can Dirac then make timing adjustments to the subs?

 

The reason why I'd like to crossover higher than 50 Hz, and into the "localizable" frequencies is my speakers, while able to play lower frequencies, apparently distort enough for me to prefer them playing above 80 Hz. Or maybe it's the amp running out of steam. But I tried using the x/o built into my subs to x/o at 80 Hz (they are fixed at that point) and preferred the sound to the subs reinforcing the lower frequencies.

 

I'm familiar with REW and use it quite a bit, although I haven't yet worked with time delays. I thought Dirac would take care of that, though. Anyway, can we set different delays at different frequencies? Maybe I was wrongly assuming that what could be delayed was a whole stream being processed together and you couldn't just delay certain frequencies within a stream in a signal. Maybe that's good news.

 

Thanks for the input!!

[dallasjustice]

I use the DEQX as a DAC, Pre, crossover and delay. I use DIRAC as well. It works very well together. According to Flavio DIRAC does handle some delay but I still think you are always better off doing delay manually if the subs will be on opposing walls. That's how I use my 2 JLF113 subs. The idea is for all sound to reach the seated position together. That's easier said than done. However, you can come very close to the point where the subs totally disappear. Can't be done without independent delays for R/L and each sub. You could play with an asymmetric crossover at a lower frequency. For example, you can cross your 804s over with a steeper slop than the sub thus giving you the ability to let the R/L play down closer to 50hz. I use a similar asymmetric crossover. It measures best and sounds better. With the DEQX you could set up 4 different crossovers and then test each one on- the- fly to see which you prefer. The HDP-4 is a nice unit. My only criticism is the sub out is only 1 CH. I need different delays between my front and back subs so I send the sub out into a xilica which gives me up to 4 independent subs out each with independent delays.

That was a quick reply!

 

How do you use your HDP-4? As DRC and digital processor only, or also as DAC/preamp? Why did you choose this unit? Not challenging, of course, but rather understanding the drivers behind the decision. Replacing a $30k DAC is certainly something!

 

So you are using Dirac on the computer, and later crossover at the HDP-4, correct? Can Dirac then make timing adjustments to the subs?

 

The reason why I'd like to crossover higher than 50 Hz, and into the "localizable" frequencies is my speakers, while able to play lower frequencies, apparently distort enough for me to prefer them playing above 80 Hz. Or maybe it's the amp running out of steam. But I tried using the x/o built into my subs to x/o at 80 Hz (they are fixed at that point) and preferred the sound to the subs reinforcing the lower frequencies.

 

I'm familiar with REW and use it quite a bit, although I haven't yet worked with time delays. I thought Dirac would take care of that, though. Anyway, can we set different delays at different frequencies? Maybe I was wrongly assuming that what could be delayed was a whole stream being processed together and you couldn't just delay certain frequencies within a stream in a signal. Maybe that's good news.

 

Thanks for the input!!

[LewinskiH01]

Thanks again.

 

What does Dirac do for you that the DEQX doesn't, beyond time delay? Or is it the ability to manually control the time delay?

 

Which Xilica model are you using? So I understand you run the subs in dual mono, and with different time delays to each for which you use the Xilica. Are you taking analog out of the DEQX, doing ADC in the Xilica, separating into two signals, and then DAC to send to each sub? This reminds me of some experiments described by Floyd Toole on his book "Sound Reproduction", a very interesting book BTW.

 

Did you consider a QOL at the time you were looking into the DEQX?

 

I need to go continue reading, but route seems a very good one. Thank you again!!

[LewinskiH01]

Anybody has a different point of view? I would be surprised if nobody did!

[beanbag]

Anybody has a different point of view? I would be surprised if nobody did!

 

Yes, I run option B.

 

My DACs cost $27 each with free shipping from Amazon, so buying a second or third one is no big deal. Hey, if this system is good enough for Linkwitz, it's good enough for me!

DSP_challenge

 

I don't run a preamp, but have the DAC go straight to the amp.

The nanodigi has volume control via a generic remote control

 

I used to run system A, but then I decided that I needed three channels of XO and no extra A->D->A step.

 

In either system A or B, you are supposed to set the XO and time alignment without DRC first, and then later turn on DRC later.

 

Otherwise, you will have to buy an integrated XO and DRC solution, such as Trinnov et al.

 

PS: I suggest you search on a forum like AVSForum or some other home theater forum where people are not purist and paranoid about applying EQ or convolving their input signals.

[flak]

Dirac Live will compensate for up to a 10 milliseconds delay.

 

If digital crossovering is necessary there are different valid solutions and products but personally I think that a stereo version of Dirac Live with downstream crossovering with a miniDSP unit (as also suggested in the link from beanbag) can be a cost effective, relatively simple and proven solution.

Either two ways: Building a 2way crossover | MiniDSP

or 3/4 ways: Stereo 3/4 way Crossover | MiniDSP

 

Ciao, Flavio

[LewinskiH01]

Yes, I run option B.

 

My DACs cost $27 each with free shipping from Amazon, so buying a second or third one is no big deal. Hey, if this system is good enough for Linkwitz, it's good enough for me!

DSP_challenge

 

I don't run a preamp, but have the DAC go straight to the amp.

The nanodigi has volume control via a generic remote control

 

I used to run system A, but then I decided that I needed three channels of XO and no extra A->D->A step.

 

In either system A or B, you are supposed to set the XO and time alignment without DRC first, and then later turn on DRC later.

 

Otherwise, you will have to buy an integrated XO and DRC solution, such as Trinnov et al.

 

PS: I suggest you search on a forum like AVSForum or some other home theater forum where people are not purist and paranoid about applying EQ or convolving their input signals.

 

Thanks for the alternative view. I looked into the DSP Challenge you linked to. It is indeed an elegant solution, provided the DACs' analog section can drive an amp as well as a good preamp can. My current DAC, while very good as such, is not as good at driving my amp as my preamp is. And this is a $1k DAC...so having 2 would be a significant investment and yet they wouldn't drive my amp as well as I have it today.

 

It doesn't mean I'm ditching the concept, though. I'm intrigued to play with this configuration after a Squeezebox Touch that's driving powered Audioengine speakers. Could be a fun little project to get my toes wet with this.

 

How do you like thehometheatershack.com forum? I go there for REW-related stuff and some people seem to be knowledgeable.

[LewinskiH01]

Dirac Live will compensate for up to a 10 milliseconds delay.

 

If digital crossovering is necessary there are different valid solutions and products but personally I think that a stereo version of Dirac Live with downstream crossovering with a miniDSP unit (as also suggested in the link from beanbag) can be a cost effective, relatively simple and proven solution.

Either two ways: Building a 2way crossover | MiniDSP

or 3/4 ways: Stereo 3/4 way Crossover | MiniDSP

 

Ciao, Flavio

 

Ciao, Flavio.

 

Thanks for chiming in. The miniDSP 2x4 is an alternative I'm considering. But I guess I'm being a bit obsessive about adding a u$160 ADC+DAC unit in between my preamp and amp...I'm coming from being a purist...bear with me as I let the concept sink in :-)

Need to try it and hear for myself if the miniDSP adds noise/diminishes transparency. I did find comments online about it introducing noise...

 

You can surely help me with this one: can Dirac introduce a delay in signals, say below 80 Hz, even if the whole frequency spectrum goes through one stereo DAC after the server with Dirac, through the preamp, and then into the miniDSP and from there to the subs anything below 80 Hz and to the main amp everything above? So the mains would play a signal thay is delayed vs what the subs would be playing? Or do I need to separate the digital signals and then turn them into analog, with the delay built in?

 

BTW, how significant are the 10 milliseconds in compensation? My room is 5x5x2.4m...well, not exactly a square place with 4 brick walls, but would need a long explanation. Speakers are 3m apart and I sit about 2.7m from each. I'm guessing it's more than enough, but not clear why you answered with the figure.

 

Chau!

[beanbag]

Thanks for the alternative view. I looked into the DSP Challenge you linked to. It is indeed an elegant solution, provided the DACs' analog section can drive an amp as well as a good preamp can. My current DAC, while very good as such, is not as good at driving my amp as my preamp is. And this is a $1k DAC...so having 2 would be a significant investment and yet they wouldn't drive my amp as well as I have it today.

 

It doesn't mean I'm ditching the concept, though. I'm intrigued to play with this configuration after a Squeezebox Touch that's driving powered Audioengine speakers. Could be a fun little project to get my toes wet with this.

 

How do you like thehometheatershack.com forum? I go there for REW-related stuff and some people seem to be knowledgeable.

 

I would suggest you buy one or two $27 DACs to drive the subs, and keep your DAC and preamp to drive the amp and main speakers. For now, just match the volume control on the preamp and the subs, and then don't touch them any more. Use the nanodigi, or even minidsp (if you only want 2 way) to control the master volume. Right now, your goal is to get this new setup up and running to try out DRC + XO. I assure you the sound quality is either equal, or barely worse, than optimal. Once you are done, you can reconsider what upgrades you want to do for sound quality.

 

I haven't posted on HTS forum because I haven't had any questions yet. I followed the REW guide to get a basic set of freq response measurements. I'm sure if I have more specific questions, I would go back there to search or ask.

[flak]

Ciao, Flavio.

 

Thanks for chiming in. The miniDSP 2x4 is an alternative I'm considering. But I guess I'm being a bit obsessive about adding a u$160 ADC+DAC unit in between my preamp and amp...I'm coming from being a purist...bear with me as I let the concept sink in :-)

Need to try it and hear for myself if the miniDSP adds noise/diminishes transparency. I did find comments online about it introducing noise...

 

You can surely help me with this one: can Dirac introduce a delay in signals, say below 80 Hz, even if the whole frequency spectrum goes through one stereo DAC after the server with Dirac, through the preamp, and then into the miniDSP and from there to the subs anything below 80 Hz and to the main amp everything above? So the mains would play a signal thay is delayed vs what the subs would be playing? Or do I need to separate the digital signals and then turn them into analog, with the delay built in?

 

BTW, how significant are the 10 milliseconds in compensation? My room is 5x5x2.4m...well, not exactly a square place with 4 brick walls, but would need a long explanation. Speakers are 3m apart and I sit about 2.7m from each. I'm guessing it's more than enough, but not clear why you answered with the figure.

 

Chau!

 

Chau!

 

Yes, Dirac Live will correct a displacement of the subwoofer up to max.10 milliseconds... the speed of sound is 1,125 ft/ms so 10 milliseconds are something like 11 feet.

 

Flavio

[LewinskiH01]

Hello Flavio.

 

Just to make sure I get this right:

1) if I wanted to run Dirac at the server, outputting through a stereo DAC, through a preamp, then into an active crossover and from there run two subs below 80Hz and into a main amp above 80Hz, I would need the two-channel version of Dirac. Right?

 

2) if I wanted to run Dirac at the server, outputting into a DEqX to act as a crossover and DAC, into the two subs and main amp, I would also need the two-channel version, right?

 

3) if I wanted to run Dirac at the server, going into a miniDSP nanoDIGI, from there into 2 stereo DACs, one driving the subs and one driving the main amp, then I would need the multichannel version of Dirac?

 

Thank you!

[flak]

Hello Lewinski,

my understanding is that in all those instances the crossovering is done downstream so there is no reason to use the multichannel version

 

Ciao:) Flavio

[LewinskiH01]

Thanks for the quick reply.

 

So what would be an example of Dirac running on a server (as opposed to miniDSP Dirac versions) and needing the multichannel version?

 

Cheers

[flak]

Thanks for the quick reply.

 

So what would be an example of Dirac running on a server (as opposed to miniDSP Dirac versions) and needing the multichannel version?

 

Cheers

 

A home theater PC with 5.1 or 7.1 channels

 

Ciao, Flavio

[retro]

A home theater PC with 5.1 or 7.1 channels

 

Ciao, Flavio

 

Or an Audio PC with digital active crossovers..

[LewinskiH01]

Or an Audio PC with digital active crossovers..

 

Right. But how is that different from option 3) I suggested above, to which Flavio replied the multi channel version was not needed?

[retro]

Right. But how is that different from option 3) I suggested above, to which Flavio replied the multi channel version was not needed?

 

Read this thread. All of it:

 

http://www.computeraudiophile.com/f23-dsp-room-correction-and-multi-channel-audio/doing-crossovers-jriver-dirac-possible-or-not-20809/

 

To sum up, you can do everything within a pc with the help of jriver and asiobridge. You could call this option D, but I would rather call it option A since this is a solution requiring no extra hardware. IMO a neater and smarter solution. You would then need the multichannel version of Dirac, and a multichannel soundcard or dac. I use a Lynx TwoB soundcard which drives the amps directly, with the volume being controlled by jriver. No need for a preamp. Alternatively, you could use a multichannel dac like the Exasound E28.

[rcohen]

Not sure if you've considered this, but here's how I'm currently doing it:

 

I output Dirac to HDMI, then do bass management in my pre-amp the usual way. The pre-amp handles levels and time alignment for two subs. I used Audyssey to calibrate both, but disabled Audyssey room correction. The DAC happens inside the pre-amp the usual way. The bass management crossover is naturally happening in the digital domain.

 

This seems to be work quite well.

 

An alternative would be to use the built-in bass management features in Windows. These are on by default, so you need to disable them if you don't want them!

 

Another alternative would be to use JRiver + Audiolense XO for more flexibility with routing, crossovers, and more channels. I wish all that was possible with Dirac.

[LewinskiH01]

I guess what you are calling a preamp is actually an AV processor. I'm leary of going down this route considering my purist approach to two-channel so far.

 

I'm now leaning towards running Dirac or Acourate on the server and setting digital crossovers there, then outputing to a multichannel DAC, and to drive the amps directly from the DAC. Along the lines of what I said above, I have significant thinking ahead of me. Dropping a very nice preamp for a DAC with digital volume control is not something I can easily swallow. But it doesmake sense and would be an elegant solution. And it would allow me to actively bi/tri-amp the stereo speakers and time-correct the drivers after getting rid of the passive crossovers, per Mitcho's article.

 

Lots of potential!!

 

Thanks for the continued feedback!

[rcohen]

Here's the one I have. Onkyo calls it a pre-amp, but yes, an AV processor is a type of pre-amp.

Preamplifiers | Onkyo USA

 

I've heard a lot of people say they like the sound from the Marantz pre-amps better, although room correction software like Dirac, Acourate, or Audiolense tends to cancel out the subtle frequency response differences in DACs, pre-amps, amps, etc.

 

I'm not so sure you need to be leery of high quality AV pre-amps. They tend to have all the good features.

 

With a 24-bit signal to the DAC, digital volume control shouldn't be audible.

 

I'm very interested to hear how your active bi/tri-amp project goes.

[LewinskiH01]

I'm very interested to hear how your active bi/tri-amp project goes.

 

My implementation is going to take a good del of time. First I need to come to terms with all of this. Budgeting constraints and logistics of every single piece to where I live are a big pain in the rear, too.

 

It's looking like my first step will be getting Dirac or Acourate in my server and do DRC with the system as-is. In a few months I might get a multichannel DAC/DEQX/AV processor, and start actively crossovering the subs and the mains. Next year a SS amp to drive woofers in the mains, and so on. I will be posting my findings, but don't expect weekly updates :-)

[rcohen]

My implementation is going to take a good del of time. First I need to come to terms with all of this. Budgeting constraints and logistics of every single piece to where I live are a big pain in the rear, too.

 

It's looking like my first step will be getting Dirac or Acourate in my server and do DRC with the system as-is. In a few months I might get a multichannel DAC/DEQX/AV processor, and start actively crossovering the subs and the mains. Next year a SS amp to drive woofers in the mains, and so on. I will be posting my findings, but don't expect weekly updates :-)

I have no experience with this, but it looks to me like JRiver and optionally Audiolense XO would be much more straightforward effective than doing it with Dirac and/or Acourate, if you want to do the crossover in your computer. This is also a cost effective route. The only thing is you'd need some kind of multi-channel DAC. You could use HDMI and a 7.1 HDMI pre-pro/receiver, MOTU 192HD, Lynx Aurora, Antelope Orion, or exaSound e18. It looks like Lynx Aurora is very commonly used by recording studios.

 

If you do the crossover outside the computer, then it looks like a DCX2496 would be a cost effective option, although not as flexible as using JRiver and/or Audiolense XO for the crossover. In that case, Dirac would work, but you'd have 2 stages of ADC/DAC. Probably not an issue with 24/96 resolution and EQ correction, but not exactly purist.

 

From what I can tell, Audiolense XO and Acourate have similar capabilities, but Audiolense XO looks easier to use.

 

Unfortunately, using Dirac with a computer based crossover (rather than external) appears to be a big mess and full of compromises, which is a shame, because I have use Dirac, and otherwise, I really like it.

[retro]

Unfortunately, using Dirac with a computer based crossover (rather than external) appears to be a big mess and full of compromises

 

Not at all..