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**miniDSP DDRC-88A Official Thread**8-channel AI/AO Dirac Live in a box

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#1 · (Edited)
Guys,

This is a dedicated thread on the MiniDSP product called DDRC-88A home theater in a box for those who are interested in Dirac Live Room Equalization solution. Only applicable with existing pre/pro/receivers that have an 8-channel analogue output to separate amps.

What is Dirac Live?
Dirac Live digital room correction technology optimizes the sound system both in terms of it's impulse response as well as the magnitude frequency response. Dirac accomplishes room correction through a technique called mixed phase. I.e. it is not IIR nor FIR, but something in between.
A technical write-up on Dirac Live by Mathias Johansson from Dirac's website is here: http://www.dirac.se/media/12044/on_room_correction.pdf

Details of the DDRC-88A are available here: http://www.minidsp.com/products/dirac-series/ddrc-88a

Wiring diagram hookup for the DDRC-88A:


Owner's manual is available.


Cost is under a grand USD - not including shipping.
  • For European AVS members, contact Homestudio with details provided by Keith Barnes in post number 522.
  • For UK AVS members, contact Kalibrate with details provided by Keith Barnes in post number 593.
  • The rest of the world will have to order from MiniDSP based in Hong Kong.

Again this is an external box solution for:
  1. those who have external amps to drive speakers; or
  2. those who have active speakers.
If you have a receiver with internal amps, sorry it's not going to help much.


The DDRC-88A has both balanced and un-balanced inputs via Phoenix terminal blocks. A solution for those with XLR pre-outs has been given by miniDSP in their forum thread post number 17019. MiniDSP recommends to:
  • buy a short XLR patch cable;
  • Cut it in the middle;
  • Use the XLR male to bare stripped wire for the DDRC OUT. You just "screw" the bare stripped wire to the pluggin phoenix connector we provide in the package (see user manual); and
  • Use the XLR female to bare stripped wire for the DDRC IN.
AVS member Jerry has provided step-by-step details for XLR cable connection in post number 729. Post up-dated to include heat-shrink for a more professional looking finish. Thanks Jerry!


Analogue input and output connection details.
  1. MiniDSP has confirmed that it's possible to have a mixture of balanced and unbalanced signals. One has to take care of the gain structure - see 2nd post for additional information.
  2. On the analogue input side; use either the balanced or the unbalanced connection - not both on a per channel input basis.
  3. It is also possible to have unbalanced input and balanced output or the other way around.
  4. On the output side, both the the balanced and unbalanced terminals are active; i.e. 'hot'. So both can be used at the same time.


Features:
  • Bypass of the DDRC-88A is available. Good for those who would like to compare their current flavor of room correction such as Audyssey, ARC, YPAO, MACC, AccuEQ, PEQ, etc. vs. Dirac Live. Note when Dirac Live is ON, the REQ within the pre/pro/receiver needs to be disabled with distances/levels set to zero. See Markus post number 611 for details.
  • Correction is adjustable for start and end frequency as well as tilting to a custom house curve. I.e. One can start from 20Hz up to 1kHz with a 10dB tilt and no correction below 20Hz or above 1kHz.
  • Can store up to 4 presets of adjustable room curves.:) Dirac Live has single seat positioning (often referred to as the money seat) or a wider sofa seating positioning measurement options. The single and sofa seat + 2 more can be saved into the presets. This would allow some flexibility in tuning the sound depending on listening situation. I.e. having family/friends over vs. critical listening by yourself. Note that an unlimited number of projects can be saved on the PC for loading into anyone of the presets.
  • Can do multi-zones. I.e. Up to four 2-channel stereo systems in the home, see post number 4 for additional details.

Current issues:
  1. Has a maximum of 7.1 channels.
  2. If you have height/wides/ceiling speakers (Dolby Atmos, Auro3D, DTS:X), you may want to consider an additional DDRC-88A solution to go beyond 8 channels. (Edit: AVS members westmd and Keith Barnes have successfully implemented a dual DDRC-88A setup. westmd in post number 4,900 and Keith Barnes in post number 8,675 with the tutorial in post number 8,683.)
  3. Sampling resolution is capped at 48kHz, might be a disappointment for those with multi-channel hi-rez files. I.e. 192kHz/24bit.
  4. Have to use MiniDSP's microphone for in room acoustical measurement with Dirac. Model number UMIK-1. Post number 18,754 in miniDSP forum explains the reasons for this.
  5. No remote trigger to start or IR code for ON/OFF operation. There could be a potential issue when the unit losses power - may cause a thump to the downstream speaker. Suggested to leave the unit on all the time and this may not please some.

Trouble shooting:
  • If the front light is OFF and the switch mode power adapter is ON (i.e. showing a green light. Edit: Keith Barnes advised that not all units power adapter have a light to indicate it is powered ON in post number 8,937) most likely the internal fuse needs replacing. Specs for the fuse is 2Amp 250v 20mm x 5mm Slow Blow. Revised fuse rating by miniDSP as advised by Markus in post number 9,186.
 
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#11,023 ·
Not in my case. When I use dolby surround, it produces sound from LR and 4 ceiling speakers. I play from Amazon prime using my PC.
Let's try this again. Dolby Surround takes a 2.0 signal and synthesizes sound to extend to other speakers that would not normally be getting sound. In my case, since I have a 7.1 configuration, Dolby Surround produces sound in the center and surround speakers. If I had ceiling speakers, it would produce sound from them as well. Are you claiming that it is not producing sound from your center and surround speakers as well?
 
#11,024 ·
OK, so you will be feeding a full-range left and right signal to the 88A. What signal do you want to go to the subs? Unless you extract low frequencies using bass management, then the subs either will get no signal (i.e. dead silence), or a full-range signal (which is not ideal). If you use bass management, you can select crossovers appropriate for your left and right mains, depending on how capable they are. Regardless, it is my opinion that subs handle bass better than the mains, regardless of their size. And subs can be placed to optimize bass response, while mains are normally placed to optimize imaging. Rarely will a speaker placed to optimize imaging also be optimized for bass response.

There is no such thing (in my mind) as stereo subs. Low frequency signals, regardless of their origin, permeate the listening space, and it is very difficult to localize the bass source. Of course, you may have a differing opinion, but all I can do is make recommendations based on my experience, and the knowledge of all the people who have advised me along the way. So, here are my recommendations which you can follow, or not:

- Set up bass management in the 88A.
- Select a reasonable crossover value (40, 60, 80Hz, etc.).
- Route the resulting low frequencies in the "LFE Mgt" channel to both subs in the Mixer screen.
- Configure Dirac to equalize the single combined sub signal.
- Don't forget to time-align the subs in the 88A Output screen.
- Enjoy.
Thanks for the great input Jerry! I was thinking along the lines of two multi way speakers with big subwoofers for each channel instead of the 2 subwoofers being handled separately by bass management together. The bass management doesn't have as much variety in it's crossover as the output crossovers do,but makes more sense in the application and Really produced SUPER results with my test system at home this evening! The BM is a nice enhancement for sure!
 
#11,025 ·
Stereo will always be my default when listening to music, but PL2x sure is fun too. I hated it before I treated the front wall, and now it's even better with the Dirac mixed phase thingamajiggies dialed in.

I think I've just scratched the surface with what can be done with the 88BM and by no means do I have any idea what I am doing... :D

As rcohen told me, listening with fresh ears and listening over long periods of time are two different things. Last night after having the system on for hours it sounded great, I wouldn't change a thing. However this morning when I turned it on using the exact same settings it sounded a little dull to my ears. Not bad, but not as good as last night. He told me that would happen, and eventually he found a curve that he loved both with fresh ears and after long listening sessions.

Ok, next up I'm going to measure (with the omnimic) how the center/sub measure together and then the same with the L/R subs. Then I can figure out the best frequencies to cross them using the BM.

I haven't even tried to include the nearfield sub yet. Should be interesting. I love the fact that I have the hard numbers as far as the delays go, should make it easier to dial in the near sub.
I see you finally made it over to Dirac Carp! Nice. I hope it works out well for you. It's a tweaker's dream :D.
 
#11,026 ·
I see you finally made it over to Dirac Carp! Nice. I hope it works out well for you. It's a tweaker's dream :D.
Thanks Doc! For sure, that along with the BM plug in it's almost worth the cost simply for the fun of messing with everything. :D I know in the end you didn't need it, but did you try just using it to EQ up to 300 ish hz and no eq above that? I think in the end I will like using EQ for everything when I find the right curve(s), but for you I bet below Schroeder would be all you'd need. :)
 
#11,027 ·
Thanks Doc! For sure, that along with the BM plug in it's almost worth the cost simply for the fun of messing with everything. :D I know in the end you didn't need it, but did you try just using it to EQ up to 300 ish hz and no eq above that? I think in the end I will like using EQ for everything when I find the right curve(s), but for you I bet below Schroeder would be all you'd need. :)
Yeah, it's a great solution for below Schroeder. The thing is that with Audyssey in LR bypass I get my unmolested 2 channel and for HT the most recent version of Audyssey actually does a pretty good job. Not quite as good as Dirac, but good enough that the added complexity of the 88A just wasn't worth it to me. If it were bomb proof I'd probably have kept it to be honest. But sometimes strange things happen with the 88A. And that's not to bash it, because they're nearly always solvable, but the benefit/aggravation curve was bent just a little more towards Audyssey. At least right now :D. I keep an eye out on this thread though since there is no doubt it is a better solution than Audyssey overall. Not even close in a lot of ways. Just in the ways that matter most to me in my current configuration it still wasn't enough.

But add sub/satellite crossover optimization, ala Dirac Unison, and I'll be back. ;) :D
 
#11,028 ·
WOAH!!! When loading a configuration into the 88BM just now I got a VERY loud pop sound. Not a bass thud kind of pop, a much higher frequency and unsettling pop sound. Molon Labe warned me that this happened to him with the 88A but I hadn't experienced it yet. That wasn't fun, I hope it doesn't happen every time I load a configuration into the 88BM.
 
#11,029 ·
WOAH!!! When loading a configuration into the 88BM just now I got a VERY loud pop sound. Not a bass thud kind of pop, a much higher frequency and unsettling pop sound. Molon Labe warned me that this happened to him with the 88A but I hadn't experienced it yet. That wasn't fun, I hope it doesn't happen every time I load a configuration into the 88BM.
Are you sure you're running all the latest firmware/software and ALL other apps are stopped? Did you install the Dirac Live DLL?
 
#11,030 ·
There is no such thing (in my mind) as stereo subs.
Correct. Typical listening room sizes scramble any directional low frequency information AND they create false directional information that is not in the recording. Better reduce seat to seat differences by using multiple subs with a monophonic bass signal and have higher frequencies deliver directional information.
 
#11,031 ·
I've spent the last couple of hours trying to get a single sound out of my just set up 88. I've reset to defaults using the mindsp tool a couple of times and restated my Mac a couple of times too.
When I click a channel to start a test tone I hear nothing, even with all volumes maxed out.
First thought was a hookup error or that my power amp was not functioning.
I checked all cables - correctly installed.
I pulled out each output cable from the 88 and plugged them into my pre-outs on my receiver - I can hear all my sources playing now so my amp is working fine.

Here's the set up steps I made:

1. Wire in the 88 between my receiver and power amp & sub.
2. Connect Mac via USB and Mic via USB.
3. Launch miniDSP software and check connection to 88 - success. Quit miniDSP software
4. Launch Dirac software and choose Custom System, 6 channels, 88 is already selected as Test signal playback device.
5. Choose Umik in Mic config tab, recording channel 1, cal file selected and loaded.
6. Output levels tab - Input Gain at -0, Output volume at -80. Click Test on left channel and slide Output volume up
7. Repeat all channels

Nothing is heard through any speaker or the sub.

Is there anything obvious I'm doing incorrectly?
 
#11,032 ·
^ With everything connected as you describe, and without running a Dirac calibration, are you getting sound from the AVR through the 88A to the speakers? For example, if you play the AVR speaker level-setting test tones, do the tones play through to the speakers? Make sure the 88A's output level is set to max, of course.
 
#11,033 ·
^ With everything connected as you describe, and without running a Dirac calibration, are you getting sound from the AVR through the 88A to the speakers? For example, if you play the AVR speaker level-setting test tones, do the tones play through to the speakers? Make sure the 88A's output level is set to max, of course.
Unfortunately not, nothing plays through the 88A at all. It's as if the 88A is a dead short
 
#11,035 ·
I was having USB sync issues so I removed power to the 88A and when it powered back on the loud pop occurred.
Is this also what user carp did?

2 - Dirac projects crashing software
Problem isn't DLCT crashing but corrupted project files. It's not clear what is causing corrupted DL project files.
 
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