Multiple Sub integration - MiniDSP, DCX2496, - Pros/Cons? - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 3Likes
Reply
 
Thread Tools
post #1 of 34 Old 07-07-2017, 07:22 AM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Multiple Sub integration - MiniDSP, DCX2496, - Pros/Cons?

Considering more complete control over my 6 sub setup and wanted some feedback on using the MiniDSP units or DCX2496 / iNuke units (Others?)

Currently only 2 sub outputs from AVR (delay / distance and YPAO basically only adjustments + obvious level and phase). Each of 6 subs has "auto EQ", but it isn't adjustable after it sets itself, and there of course isn't a way to have it account for the other 5 and their effect / interaction on the response.

So I guess I'm looking for a way to control, on a per-sub basis:
1) Delay
2) EQ

I've got REW installed on an old laptop (sure its an old version), also have a UMIK around somewhere. Haven't used either in a while, but presumably these can be used (updating to latest REW version) in conjunction with a MiniDSP or similar.

Any experience gained using devices which are made for this purpose would be appreciated!
Iamjcl is offline  
Sponsored Links
Advertisement
 
post #2 of 34 Old 07-07-2017, 09:20 AM
Member
 
Jag768's Avatar
 
Join Date: Aug 2015
Location: the Netherlands
Posts: 23
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 10
There's more info on this in this thread. There's also an application note from miniDSP on how to use REW/miniDSP/MSO for integration of subs in order to get max flat reponse at each seat. It takes some time to master, but it's worth it.
Jag768 is offline  
post #3 of 34 Old 07-07-2017, 10:00 AM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Quote:
Originally Posted by Jag768 View Post
There's more info on this in this thread. There's also an application note from miniDSP on how to use REW/miniDSP/MSO for integration of subs in order to get max flat reponse at each seat. It takes some time to master, but it's worth it.
Thanks!

So the MiniDSP link you mention shows the use of a DDRC-88A unit (with corresponding BM software, apparently) and using the DDRC unit to process the 7 "main" channels + 1 LFE channel, or 3 .1 channels and 5 main channels - or 8 outputs.

I'm not sure I need / want to re-process my "main" channels (maybe I should), but I also have 11 main channels (Atmos) so don't think it would work anyway. I guess the "Dirac" part of this unit is similar to the baked-in "Ypao" on a Yamaha AVR? Guessing it may be more capable...

But I was assuming I could keep my AVR main outs directly connected to their respective amps (only using internal AVR / Ypao processing for those channel) and re-process just the sub out(s) of my AVR, and "fine tune" up to 8 sub outputs with different gain/phase/time alignment/EQ settings using one of the 4x10 or 10x10 HD MiniDSP units?

So presumably I could use a Dirac / DDRC-88A to only process the two AVR sub-out channels, but does the Dirac unit do something for multiple sub setup that the 4x10 / 10x10 HD units don't do?

Thanks for any help!
Iamjcl is offline  
 
post #4 of 34 Old 07-07-2017, 10:34 AM
AVS Forum Special Member
 
andyc56's Avatar
 
Join Date: Feb 2013
Posts: 1,172
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 391
It only makes sense to use the DDRC-88A if you wish to replace your room correction (for all speakers, both subs and satellites) with Dirac.

Even if you had a DDRC-88A, and you wanted individual EQ, delay and gain for each of your 6 subs, you'd still need to get a miniDSP 4x10 or DCX2496 or similar for the subs, unless you are only running a 2-channel setup.

Having individual EQ for the subs is what allows, along with special software, reduction of the seat-to-seat variation in bass response due to room modes.

If you do end up getting a 4x10, you should get the plugin for 48 kHz sample rate (the 10x10 plugin), not the 96 kHz one. The reason is that the lower sample rate gives better frequency response accuracy when using filters that have a significant effect on the very lowest frequencies. This is illustrated in a review at the DIY Geezer site.
Jag768 likes this.

Last edited by andyc56; 07-07-2017 at 10:48 AM.
andyc56 is offline  
post #5 of 34 Old 07-07-2017, 10:57 AM
Member
 
Jag768's Avatar
 
Join Date: Aug 2015
Location: the Netherlands
Posts: 23
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 10
Quote:
Originally Posted by andyc56 View Post
It only makes sense to use the DDRC-88A if you wish to replace your room correction (for all speakers, both subs and satellites) with Dirac.

If you want individual EQ, delay and gain for each of your 6 subs, you'd still need to get a miniDSP 4x10 or DCX2496 for the subs, unless you are only running a 2-channel setup.

Having individual EQ for the subs is what allows, along with special software, reduction of the seat-to-seat variation in bass response due to room modes.

If you do end up getting a 4x10, you should get the plugin for 48 kHz sample rate (the 10x10 plugin), not the 96 kHz one. The reason is that the lower sample rate gives better frequency response accuracy when using filters that have a significant effect on the very lowest frequencies. This is illustrated in a review at the DIY Geezer site.
That's very important information indeed. Does MSO support the use of the SUB_EQ filter type?

You could also consider the C-DSP 6x8, as it is costs less than 1/3 of a Dirac DDRC-88A and also less than the 4x10 HD. I've just purchased one myself, to replace my 2x4 unit and handle 2way active fronts and 4 subs. I've just ordered the unit, it hasn't arrived yet.

Attached Thumbnails
Click image for larger version

Name:	IMG_9893-2.jpg
Views:	401
Size:	104.5 KB
ID:	2222857  
andyc56 likes this.
Jag768 is offline  
post #6 of 34 Old 07-07-2017, 11:09 AM
AVS Forum Special Member
 
andyc56's Avatar
 
Join Date: Feb 2013
Posts: 1,172
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 391
Quote:
Originally Posted by Jag768 View Post
That's very important information indeed. Does MSO support the use of the SUB_EQ filter type?
No, it doesn't. I'm not even sure what they are doing with that filter type.
andyc56 is offline  
post #7 of 34 Old 07-07-2017, 11:34 AM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Quote:
Originally Posted by andyc56 View Post
It only makes sense to use the DDRC-88A if you wish to replace your room correction (for all speakers, both subs and satellites) with Dirac.

Even if you had a DDRC-88A, and you wanted individual EQ, delay and gain for each of your 6 subs, you'd still need to get a miniDSP 4x10 or DCX2496 or similar for the subs, unless you are only running a 2-channel setup.

Having individual EQ for the subs is what allows, along with special software, reduction of the seat-to-seat variation in bass response due to room modes.

If you do end up getting a 4x10, you should get the plugin for 48 kHz sample rate (the 10x10 plugin), not the 96 kHz one. The reason is that the lower sample rate gives better frequency response accuracy when using filters that have a significant effect on the very lowest frequencies. This is illustrated in a review at the DIY Geezer site.
GREAT info - thank you!
Iamjcl is offline  
post #8 of 34 Old 07-07-2017, 11:39 AM
AVS Forum Special Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: Northern Okan range (NW Cascades region)
Posts: 7,941
Mentioned: 104 Post(s)
Tagged: 0 Thread(s)
Quoted: 2347 Post(s)
Liked: 2110
I wouldn't suggest the dcx, it only has 3x6, and like the inuke can't do sub 20hz (not without filter tricks at least...)

Stick with the minidsp or inukedsp.
BassThatHz is offline  
post #9 of 34 Old 07-07-2017, 12:48 PM
AVS Forum Special Member
 
andyc56's Avatar
 
Join Date: Feb 2013
Posts: 1,172
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 391
Quote:
Originally Posted by Jag768 View Post
You could also consider the C-DSP 6x8, as it is costs less than 1/3 of a Dirac DDRC-88A and also less than the 4x10 HD.
That looks like a good choice - much cheaper than the 4x10 and still has the 15 msec max delay, rather than the 7.5 msec max delay of the non-HD 2x4.
andyc56 is offline  
post #10 of 34 Old 07-08-2017, 08:18 AM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Quote:
Originally Posted by andyc56 View Post
That looks like a good choice - much cheaper than the 4x10 and still has the 15 msec max delay, rather than the 7.5 msec max delay of the non-HD 2x4.
I'm still not clear on what the differences in these units actually would be?

My needs are to basically be able to control delay per subwoofer location (I can obviously already control phase, level, x-over etc... per unit) with existing controls.

I guess the other major thing is to be able to use MSO to analyze the sound and figure out what all these parameters should be.

So not sure the $1,000 Dirac unit offers any benefit for my use (if I continue to use Ypao to process the satellite signals)? They talk about impulse response but I'm not sure what it is doing.

Also - please let me know if I have this right (abbreviated version):

1) PC runs REW and MSO apps.

2) USB UMIK is plugged into PC.

3) PC audio analog Left / Right outputs goes into an AVR input. (How do you know your PC audio analog out is flat down to 20hz? Does PC analog audio even output below 20hz...?)

4) AVR outputs to be processed / analyzed go into MiniDSP, then out to corresponding subs / amps.

5) Playback tones / signals via REW and/or MSO, save files via REW / MSO, import appropriate files into MiniDSP (using MiniDSP plugin?)

6) Unplug PC - MiniDSP is configured until you want to change or move something?

Just trying to get a grip on the connections / configuration and the process.

Thanks for any help.
Iamjcl is offline  
post #11 of 34 Old 07-08-2017, 09:02 AM
AVS Forum Special Member
 
andyc56's Avatar
 
Join Date: Feb 2013
Posts: 1,172
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 391
Quote:
Originally Posted by Iamjcl View Post
I'm still not clear on what the differences in these units actually would be?

My needs are to basically be able to control delay per subwoofer location (I can obviously already control phase, level, x-over etc... per unit) with existing controls.

I guess the other major thing is to be able to use MSO to analyze the sound and figure out what all these parameters should be.

So not sure the $1,000 Dirac unit offers any benefit for my use (if I continue to use Ypao to process the satellite signals)? They talk about impulse response but I'm not sure what it is doing.

Also - please let me know if I have this right (abbreviated version):

1) PC runs REW and MSO apps.

2) USB UMIK is plugged into PC.

3) PC audio analog Left / Right outputs goes into an AVR input. (How do you know your PC audio analog out is flat down to 20hz? Does PC analog audio even output below 20hz...?)

4) AVR outputs to be processed / analyzed go into MiniDSP, then out to corresponding subs / amps.

5) Playback tones / signals via REW and/or MSO, save files via REW / MSO, import appropriate files into MiniDSP (using MiniDSP plugin?)

6) Unplug PC - MiniDSP is configured until you want to change or move something?

Just trying to get a grip on the connections / configuration and the process.

Thanks for any help.
MSO should be viewed as an advanced technique, used when you want to optimize the flatness of the bass response at multiple seating locations simultaneously. If you only care about the response at a single seating location, MSO isn't necessary. It's not for everybody, and its use should only be undertaken after fully coming up to speed on REW measurements.

As I mentioned before, the Dirac unit is unnecessary unless you wish to give up on your AVR's room correction and use Dirac instead. I believe Jag768 referenced that article in connection with MSO because it's concise and well-written. The guys from miniDSP are much better writers than I am, so that MSO tutorial has helped some people that don't have the Dirac unit, even though it's written for use with that unit.

The usage of REW is best explained in "Getting Started With REW: A Step-by-Step Guide" by @AustinJerry . In it, he explains how to use REW with a computer having HDMI output and AVR with HDMI input. In this way, one needn't worry about the frequency response of the computer's analog sound device. The frequency response of the microphone itself is measured by the manufacturer (or calibrator) and provided in the form of a calibration file, which REW uses to correct its data for the microphone's frequency response imperfections.

Briefly, connections will be:
Laptop HDMI out -> AVR HDMI in
UMIK USB out -> USB port on laptop
andyc56 is offline  
post #12 of 34 Old 07-08-2017, 09:19 AM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Quote:
Originally Posted by andyc56 View Post
MSO should be viewed as an advanced technique, used when you want to optimize the flatness of the bass response at multiple seating locations simultaneously. If you only care about the response at a single seating location, MSO isn't necessary. It's not for everybody, and its use should only be undertaken after fully coming up to speed on REW measurements.

As I mentioned before, the Dirac unit is unnecessary unless you wish to give up on your AVR's room correction and use Dirac instead. I believe Jag768 referenced that article in connection with MSO because it's concise and well-written. The guys from miniDSP are much better writers than I am, so that MSO tutorial has helped some people that don't have the Dirac unit, even though it's written for use with that unit.

The usage of REW is best explained in "Getting Started With REW: A Step-by-Step Guide" by @AustinJerry . In it, he explains how to use REW with a computer having HDMI output and AVR with HDMI input. In this way, one needn't worry about the frequency response of the computer's analog sound device. The frequency response of the microphone itself is measured by the manufacturer (or calibrator) and provided in the form of a calibration file, which REW uses to correct its data for the microphone's frequency response imperfections.

Briefly, connections will be:
Laptop HDMI out -> AVR HDMI in
UMIK USB out -> USB port on laptop
Thanks - Understood. Didn't think about HDMI audio out at all - brain fail.

Maybe the MiniDSP article referencing the Dirac unit in conjunction with MSO was throwing me.

So essentially, what is it that MSO would want to "adjust" inside the MiniDSP, after it has the requisite info about what each of your subs is doing individually (at multiple locations)?

I would presume:
1) Level
2) Phase
3) Delay
4) X-over
5) EQ

Or are there additional parameters it adjusts / controls by way of the MiniDSP?
Iamjcl is offline  
post #13 of 34 Old 07-08-2017, 11:29 AM
Member
 
Jag768's Avatar
 
Join Date: Aug 2015
Location: the Netherlands
Posts: 23
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 10
Quote:
Originally Posted by Iamjcl View Post
Thanks - Understood. Didn't think about HDMI audio out at all - brain fail.

Maybe the MiniDSP article referencing the Dirac unit in conjunction with MSO was throwing me.

So essentially, what is it that MSO would want to "adjust" inside the MiniDSP, after it has the requisite info about what each of your subs is doing individually (at multiple locations)?

I would presume:
1) Level
2) Phase
3) Delay
4) X-over
5) EQ

Or are there additional parameters it adjusts / controls by way of the MiniDSP?
MSO adjusts whatever you supply it with. So you can define the filters you use yourself. I agree with Andy on this, you can use the hdmi out of your computer or alternatively, the analog audio out. And the USB mic. And then first run some measurements with REW, also with the external timing reference. After you got a little familiar with REW, start reading the MSO tutorial / documents. MSO takes some time to master, especially if you're new to all this.

One tip: make sure that your AVR is set up the way you want it to, before making the measurements. So set delays, levels, EQ en the xover. And write those values down before you start (otherwise you'll forget).
Jag768 is offline  
post #14 of 34 Old 07-08-2017, 02:39 PM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Quote:
Originally Posted by Jag768 View Post
MSO adjusts whatever you supply it with. So you can define the filters you use yourself. I agree with Andy on this, you can use the hdmi out of your computer or alternatively, the analog audio out. And the USB mic. And then first run some measurements with REW, also with the external timing reference. After you got a little familiar with REW, start reading the MSO tutorial / documents. MSO takes some time to master, especially if you're new to all this.

One tip: make sure that your AVR is set up the way you want it to, before making the measurements. So set delays, levels, EQ en the xover. And write those values down before you start (otherwise you'll forget).
Thanks - I guess I'll need to look into a MiniDSP or similar in order to get started, otherwise I can't do much about the REW results (unless I only use 2 subs, since I only have 2 independently adjustable sub-outs from AVR).

My MLP can be pretty good (by ear) but the surrounding seats are bad - hence the 6 subs. Using the spaced out 6, all are now pretty fair, but it seems muddy to me at MLP, but I don't have those massive wrong-sounding nulls / phase issues in some of the guest seats.

My other alternative is to set memories / remote sequences to select "one person only" or "whole room" setups, but that's kind of a kludge.
Iamjcl is offline  
post #15 of 34 Old 07-08-2017, 02:43 PM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Also - as I've only really had the one adjustment of phase to independently adjust the 6 subs to reinforce one another and not cancel them out, I guess what I've really needed is a distance / delay control for each (and not the whole group of 6 collectively). I was under the impression they were sort of the same (phase and delay), but obviously this appears not to be the case. And any attempt at EQing the whole group of 6 clearly isn't going to be efficient.
Iamjcl is offline  
post #16 of 34 Old 07-09-2017, 05:33 AM
Member
 
Jag768's Avatar
 
Join Date: Aug 2015
Location: the Netherlands
Posts: 23
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 10
Well, in that case, MSO sounds like a good idea. It 'll probably help a lot. Once you've done the measurements, you can post your project in this topic, so others can help you setting it up. Take into account that you'll probably won't get it right the first round.
Jag768 is offline  
post #17 of 34 Old 07-10-2017, 12:40 PM
AVS Forum Special Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: Northern Okan range (NW Cascades region)
Posts: 7,941
Mentioned: 104 Post(s)
Tagged: 0 Thread(s)
Quoted: 2347 Post(s)
Liked: 2110
Quote:
Originally Posted by andyc56 View Post
Quote:
Originally Posted by Jag768 View Post
You could also consider the C-DSP 6x8, as it is costs less than 1/3 of a Dirac DDRC-88A and also less than the 4x10 HD.
That looks like a good choice - much cheaper than the 4x10 and still has the 15 msec max delay, rather than the 7.5 msec max delay of the non-HD 2x4.
Only 15? That isn't very much. The dcx does like 500ms. Hundreds of feet...

My dsp will support 1000ms of delay, but pc's have lots of ram... that's only 0.8mb of ram per channel @ 32/192.
BassThatHz is offline  
post #18 of 34 Old 07-10-2017, 08:05 PM
AVS Forum Special Member
 
andyc56's Avatar
 
Join Date: Feb 2013
Posts: 1,172
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 391
Quote:
Originally Posted by BassThatHz View Post
Only 15? That isn't very much. The dcx does like 500ms. Hundreds of feet...
Yup. It's still small, but at least it's better than the 7.5 msec maximum of the non-HD 2x4. The regular 2x4 maximum delay gets a little worse still (7.2 msec) when the 2x4 Advanced plug-in is used. It's stated as 7.5 msec in the plugin datasheet, but the Audioholics video about sub integration using the miniDSP clearly shows a maximum of 7.2 msec.

Domestic applications don't need 500 msec delay, but if one has a big room and a combination of near-field subs and much more distant ones, the 15 msec maximum might not be enough. If the most distant sub is 20 feet further away from the MLP than the closest one, the needed correction will exceed the 15 msec maximum.
andyc56 is offline  
post #19 of 34 Old 07-12-2017, 01:17 PM
AVS Forum Addicted Member
 
Stereodude's Avatar
 
Join Date: Jan 2002
Location: Detroit Metro Area
Posts: 14,140
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 3401 Post(s)
Liked: 2491
FWIW, MiniDSP doesn't really have a good unit for subwoofers. IMHO, the Balanced 2x4 unit is probably the closest one to being suited for the job if the max delay is acceptable. The ones with 96kHz sample rates have pretty serious overshoot if you use steep low frequency filters. The 2x4 Balanced is voltage limited on the input and output side and the 4x10 does better in this regard, but again the overshoot. I suggested they make a model targeting subwoofer usage with double the voltage capability of the 2x4 balanced, but with a lower than 48kHz sampling rate to have even less overshoot, but so far they haven't made it.

If you're careful you can use the 2x4 balanced and not have the voltage limits clip or limit your LFE chain and it has the best overshoot performance. If you need a lot of delay I'm not sure what product to recommend.
Stereodude is online now  
post #20 of 34 Old 07-12-2017, 02:21 PM
AVS Forum Special Member
 
diy speaker guy's Avatar
 
Join Date: Jan 2011
Posts: 1,403
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 503 Post(s)
Liked: 503
The overshoot shown in the article could be corrected with other dsp filters unless I'm misunderstanding something. And the article says the LFE management is more stable in the overshoot issue than the regular channels. Not sure if the LFE management includes the high pass fitter, I don't actually own one yet but I just ordered the 2x4 HD earlier today. I'm hoping the overshoot won't be an issue and I'm pretty sure I can deal with it if it turns out to be. I hope.
diy speaker guy is online now  
post #21 of 34 Old 07-12-2017, 04:53 PM
AVS Forum Addicted Member
 
Stereodude's Avatar
 
Join Date: Jan 2002
Location: Detroit Metro Area
Posts: 14,140
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 3401 Post(s)
Liked: 2491
What article?
Stereodude is online now  
post #22 of 34 Old 07-12-2017, 05:24 PM
AVS Forum Special Member
 
diy speaker guy's Avatar
 
Join Date: Jan 2011
Posts: 1,403
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 503 Post(s)
Liked: 503
the link in post 4
diy speaker guy is online now  
post #23 of 34 Old 07-12-2017, 07:02 PM
AVS Forum Special Member
 
andyc56's Avatar
 
Join Date: Feb 2013
Posts: 1,172
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 391
Quote:
Originally Posted by diy speaker guy View Post
The overshoot shown in the article could be corrected with other dsp filters unless I'm misunderstanding something.
It's a messy problem for software developers, as for very low cutoff frequencies the filters behave as if they had different biquad coefficients from the ones computed by the software and loaded by the user from the biquad text file. The developer would have to have a detailed and accurate model of what's going on inside the chip, and maybe even the vendor's plugin software too. Even then, other problems remain, as such a model would only yield the actual (wrong) filter behavior for a given set of coefficients, not how to alter the computed biquad coefficients so the actual filter behavior closely matches the analog filter prototype (if this is even possible).

Last edited by andyc56; 07-12-2017 at 07:27 PM.
andyc56 is offline  
post #24 of 34 Old 07-12-2017, 07:19 PM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Quote:
Originally Posted by Stereodude View Post
FWIW, MiniDSP doesn't really have a good unit for subwoofers. IMHO, the Balanced 2x4 unit is probably the closest one to being suited for the job if the max delay is acceptable. The ones with 96kHz sample rates have pretty serious overshoot if you use steep low frequency filters. The 2x4 Balanced is voltage limited on the input and output side and the 4x10 does better in this regard, but again the overshoot. I suggested they make a model targeting subwoofer usage with double the voltage capability of the 2x4 balanced, but with a lower than 48kHz sampling rate to have even less overshoot, but so far they haven't made it.

If you're careful you can use the 2x4 balanced and not have the voltage limits clip or limit your LFE chain and it has the best overshoot performance. If you need a lot of delay I'm not sure what product to recommend.
So I've got a 10x10 HD on the way to try out for (hopefully) improving the integration of 5 / 6 sub locations around the room.

What do you mean "voltage limited"? As in clean analog output voltage? (not clipping), or has limited input voltage headroom (typical pre-amp subwoofer output voltages might or would overdrive the analog input stage?)

I'll be trying the unbalanced unit - what are it's specific issues?

This appears to be a time-consuming endeavor to try and integrate these subs, so I hate to embark on it if the main hardware that will be responsible for most of the adjustments (MiniDSP 10x10HD) is not capable of proper operation.

Are there ways to get around the issues with these units (use low input levels, low output levels, add needed gain in the sub amp instead, etc...)

Thanks
Iamjcl is offline  
post #25 of 34 Old 07-12-2017, 07:27 PM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Quote:
Originally Posted by andyc56 View Post
Yup. It's still small, but at least it's better than the 7.5 msec maximum of the non-HD 2x4. The regular 2x4 maximum delay gets a little worse still (7.2 msec) when the 2x4 Advanced plug-in is used. It's stated as 7.5 msec in the plugin datasheet, but the Audioholics video about sub integration using the miniDSP clearly shows a maximum of 7.2 msec.

Domestic applications don't need 500 msec delay, but if one has a big room and a combination of near-field subs and much more distant ones, the 15 msec maximum might not be enough. If the most distant sub is 20 feet further away from the MLP than the closest one, the needed correction will exceed the 15 msec maximum.
Don't think I'd need more than the 15msec, but would a workaround be to use sub output 1 from AVR, with a "distance" of zero set in the AVR, to drive the "far" sub input(s) of MiniDSP, and sub output 2 from AVR, with a "distance" of 15' set in the AVR for that output, to drive the "close" sub input(s) to the MiniDSP?

So in this case one input (or multiple inputs) would already have delay "built in" (provided by the AVR), and the other input(s) would have no (or less) delay - would this alleviate the issue?

I ask because I do have one location around 20' away from MLP, and one possibility is a near-field array right behind MLP. Have no idea if it is viable, but if the delay won't support it then clearly it wouldn't be anyway.

Thanks
Iamjcl is offline  
post #26 of 34 Old 07-12-2017, 07:50 PM
AVS Forum Special Member
 
andyc56's Avatar
 
Join Date: Feb 2013
Posts: 1,172
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 391
Quote:
Originally Posted by Iamjcl View Post
Don't think I'd need more than the 15msec, but would a workaround be to use sub output 1 from AVR, with a "distance" of zero set in the AVR, to drive the "far" sub input(s) of MiniDSP, and sub output 2 from AVR, with a "distance" of 15' set in the AVR for that output, to drive the "close" sub input(s) to the MiniDSP?

So in this case one input (or multiple inputs) would already have delay "built in" (provided by the AVR), and the other input(s) would have no (or less) delay - would this alleviate the issue?
This is a viable workaround, yes. If you end up using MSO, ask for specific setup instructions in the MSO thread before doing measurements. MSO doesn't directly support two independent AVR sub outputs, but for specific configurations such as yours it can be worked around.
andyc56 is offline  
post #27 of 34 Old 07-13-2017, 03:57 AM
AVS Forum Addicted Member
 
Stereodude's Avatar
 
Join Date: Jan 2002
Location: Detroit Metro Area
Posts: 14,140
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 3401 Post(s)
Liked: 2491
Quote:
Originally Posted by Iamjcl View Post
What do you mean "voltage limited"? As in clean analog output voltage? (not clipping), or has limited input voltage headroom (typical pre-amp subwoofer output voltages might or would overdrive the analog input stage?)
As in the LFE channel from many receivers / pre-pro can clip the input. Pioneer and Onkyo units can put out more voltage than the 2x4 Balanced unit can accept. The standard 2x4 can probably be clipped by any receiver's LFE output and it has a pretty weak voltage output too. I'm talking about the voltage output on the LFE channel with the channel trim at 0dB and the master volume at 0dB (reference) being higher than the MiniDSP can accept without clipping. Depending on how loudly you listen this may or may not be a problem. The workaround is to lower the channel trim on the LFE channel and be mindful of how much overall boost is being applied to the signal in the MiniDSP. Otherwise you could clip the output even if the input is good.

Quote:
I'll be trying the unbalanced unit - what are it's specific issues?
I thought you said you were getting the 10x10. AFAIK, there is no unbalanced version of it.

If you mean the 2x4 unbalanced... Good luck.
Stereodude is online now  
post #28 of 34 Old 07-13-2017, 06:34 AM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Quote:
Originally Posted by Stereodude View Post
I thought you said you were getting the 10x10. AFAIK, there is no unbalanced version of it.
I guess it has balanced and unbalanced outputs. With it not having XLRs, I just assumed it was unbalanced only. I have no use for the balanced outputs so wasn't looking too closely at it I guess.

Being that it has both balanced and unbalanced I/O, is the gain issue "better" using the balanced input terminals (vs using the RCA / unbalanced)? Or are you saying the analog I/O sections of the MiniDSP units that include balanced inputs / outputs have more headroom (using either type input / output jack) than the MiniDSP units that only have unbalanced I/O?

I'm using a Yamaha 3060 to provide the sub outs, but currently use unity gain on the 2 sub outs. This also leaves my Velodyne SC-1250 amps at very low (25-30%) gain, so I should be able to make up quite a bit of gain here if needed.

We'll see.

Thanks for the clarifications.

Last edited by Iamjcl; 07-13-2017 at 06:41 AM.
Iamjcl is offline  
post #29 of 34 Old 07-13-2017, 07:18 AM - Thread Starter
Advanced Member
 
Iamjcl's Avatar
 
Join Date: Feb 2000
Location: Down South
Posts: 874
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 32
Quote:
Originally Posted by Stereodude View Post
FWIW, MiniDSP doesn't really have a good unit for subwoofers. IMHO, the Balanced 2x4 unit is probably the closest one to being suited for the job if the max delay is acceptable. The ones with 96kHz sample rates have pretty serious overshoot if you use steep low frequency filters. The 2x4 Balanced is voltage limited on the input and output side and the 4x10 does better in this regard, but again the overshoot. I suggested they make a model targeting subwoofer usage with double the voltage capability of the 2x4 balanced, but with a lower than 48kHz sampling rate to have even less overshoot, but so far they haven't made it.

If you're careful you can use the 2x4 balanced and not have the voltage limits clip or limit your LFE chain and it has the best overshoot performance. If you need a lot of delay I'm not sure what product to recommend.
Reading your response a little more closely:

You suggest that the 4x10 HD (I assume 10x10 HD is probably the same?) has less of a I/O voltage headroom problem than the 2x4 HD?

And regarding the "96Khz sample rate" units, which ones are those? I know it was suggested here to use the 48Khz plugin with the 10x10 - Is that what you mean?

And WRT overshoot - by "Steep low frequency filters" are you talking cross-over filters or EQ / other adjustments?

I'm planning to continue using the AVR cross-overs and only use the 10x10 HD to process the LFE signals with delay, gain, and EQ.

Thanks!
Iamjcl is offline  
post #30 of 34 Old 07-13-2017, 07:22 AM
AVS Forum Addicted Member
 
Stereodude's Avatar
 
Join Date: Jan 2002
Location: Detroit Metro Area
Posts: 14,140
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 3401 Post(s)
Liked: 2491
Quote:
Originally Posted by Iamjcl View Post
I guess it has balanced and unbalanced outputs. With it not having XLRs, I just assumed it was unbalanced only. I have no use for the balanced outputs so wasn't looking too closely at it I guess.

Being that it has both balanced and unbalanced I/O, is the gain issue "better" using the balanced input terminals (vs using the RCA / unbalanced)? Or are you saying the analog I/O sections of the MiniDSP units that include balanced inputs / outputs have more headroom (using either type input / output jack) than the MiniDSP units that only have unbalanced I/O?

I'm using a Yamaha 3060 to provide the sub outs, but currently use unity gain on the 2 sub outs. This also leaves my Velodyne SC-1250 amps at very low (25-30%) gain, so I should be able to make up quite a bit of gain here if needed.

We'll see.

Thanks for the clarifications.
Please keep in mind I only have first hand, hands on experience with the 2x4 (non-HD) Balanced model. On the 2x4 Bal Balanced or RCA in perform the same in terms of voltage input because they use the same terminals. The output behavior is different. If using balanced output it has 2x the voltage swing of what you get using it singled ended (RCA). So, if you do RCA in to RCA out on the 2x4B you will get half the voltage of the input for a 6dB loss in signal strength. This means if your sub amp(s) has a balanced (XLR) input you would likely want to use it with the 2x4 Bal to avoid that 6dB loss.

The 10x10 looks to be different. It has different specs for the RCA inputs vs. the balanced terminal blocks. The RCA inputs are only rated for up to 2Vrms which you can easily exceed with the LFE output on a modern receiver if that's the real limit. FWIW, the 2x4 Bal is now rated for 4Vrms and I found it clipped at about 4.7Vrms. The balanced inputs on the 10x10 are rated to 8Vrms. You probably can't clip those as your Yamaha would most likely clip first.

It looks like you'd want to use the balanced inputs on the 10x10 using a RCA to Phoenix cable to avoid clipping the input. You could use the RCA output, but you're probably going to only get 1/4th the input voltage (for a 12dB loss). I'd recommend using a Phoenix to XLR cable from the balanced output to your Velodyne SC-1250's XLR input so the voltage output of the 10x10 is equal to the voltage input.

Last edited by Stereodude; 07-13-2017 at 07:27 AM.
Stereodude is online now  
Sponsored Links
Advertisement
 
Reply DIY Speakers and Subs

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off