TOPIC: DDRC-88A: Occasional distortion on 2 channels

Hello,

I'm running my DDRC-88A (current firmware) for 2 month now, generally it is doing a great job correcting my room.
I got a 5.1 setup running through an Onkyo TX-NR 905 AV-receiver.

But occasionally I get some kind of distortion of the audio on channels 5 & 6 - my rear speakers, right after powering on the system.

It is only noticeable when there's a signal playing on those channels, the audio sounds like being put through a noise generator - you can still hear the original audio but heavily distorted/with added noise. The volume of the affected channels stays roughly normal though.

Whenever this happens (roundabout every 15th system power-up) I restart the DDRC-88A and the noise is gone.


Any suggestions what may cause this? I hope my unit isn't faulty.

Thanks in advance,
Raphael

@ Raphael,

Mmh, this is odd indeed. Is that distortion coming at a specific time? e.g. higher than usual level?
We're wondering if you're basically experiencing some issue of saturation of the input level. Easiest would be for us to see your configuration file (i.e. project) so we can load it on our test bench. Please share that with us as a dropbox link maybe (large file).

Easiest might be to start a tech support ticket for the latter. (minidsp.desk.com)

DevTeam

When it is occuring then directly after turning on the unit, and it doesn't go away on its own then. But powercycling the DDRC-88A has always helped so far.
It is totally independant from the input level, happens on low level signals aswell as high level.

My projects target curve doesn't exceed the 0db level anywhere.
I don't think it's saturation, because the profile works fine after powercycling the unit.

Going to upload the project file/open a ticket when I get home later.

Raphael

I've just opened a ticket and attached a link to download my current project file. #10573

Thank you,
Raphael

Thanks Raphael,.

Our tech support team will get back to you directly I'm sure. They'd just need to figure some time to test your project and such.
In the mean time, please do us a favor: It's already been few times that we've heard of a similar symptoms, and it was a simple wiring issue (e.g. shield not connecting right). Please have a trial at swapping the wiring that is being used for these 2 rear speakers for both inputs and outputs.
- If the noise move to another speaker, then we know it's cabling related.
- If the noise still remain on the exact same channel then we're narrowing it down to something specific to the DDRC-88A configuration/hardware.

Makes sense?

DevTeam

Yup, I'm going to try this when the issue comes up next time.

Thanks

Not that odd considering I report this issue 3 months ago and others are having the same issue.

I've seen someone over at avsforums having the same issue aswell...

BTW, I just replaced all my RCA-cables with higher quality ones, and the issue still comes up. :/

Last time when it happened I took the DDRC-88A out of the loop by directly connecting the affected in & out RCA-cables, then noise was gone instantly. IMHO it has to come from the DDRC-88A.

I think I've narrowed it down a bit more... before the issue starts there's usually a slight "pop" sound out of the other speakers. Nothing really loud, but noticable.

@cal900: Did something come out of it after reporting it?

I was asked to reset and start all over again from scratch, which has not been possible for me to try.

They were reluctant to accept that it was the 88A at fault, but I've known all along that it is because everything was fine before and the problems started when I added the 88A to my system.

I am hoping to be able to reset and start over in a few weeks, but I don't believe that it is going to make any difference.

Dear both,

So you're in the loop, we're now trying to investigate this issue (none of our units here able to get that state after many hours running these projects) by having one unit being shipped to us as we speak. It's most likely something specific to the file + firmware + hardware.. Either one of these combination is creating the issue which is very limited considering the large amounts of unit in the field. Right now we're aware of 3-4 units top based on the tech support received, so a very small amount which makes it harder to understand the issue.

We appreciate your patience once again. Like any troubleshooting process, the basic troubleshooting we ask for (e.g. reset the unit, make sure you're running the latest firmware, send us your files, check your cabling) can indeed be felt useless by some of you and make you feel that we're not trying to address the issue but please understand our position. We're trying to isolate the information here that is useful, not trying to blame anybody.. Daily we get reports of issues when it's really 90% of the time a simple software misconfiguration issue, we got many reports of noise when indeed it was cabling. So it's worth for us to ask for information and try steps, it's worth for us to get that feedback from people having issues so we can then narrow down the problem working hand in hand with the community. Shipping units back and forth doesn't solve a problem especially if it's system triggered. Hoping this long explanation makes sense, miniDSP doesn't "ignore" customers. We're here to help and will soon update asap we test that unit that is about to ship from Adam.

Devteam

Thank you for the information devteam.

I totally understand your side of the situation, no worries.

Hope it turns out it's something that's fixable without shipping the units back.
Please keep us posted on your progress.

Raphael

tw1l1ght wrote:
That's probably me.

I've had this issue for quite some time now.

I've had a ticket open since the 23rd of October, Case No 10753, and I find the support response to be very bad.

I've done all the basic troubleshooting, and have Dropboxed my project as requested on the 29th October and haven't heard a word back since.

My unit also resets volume levels intermittently, as well as having the problems described in this thread.

I accept any piece of electronics can have problems, but we rely on support to deal with issues and more importantly, to communicate effectively.

The support team here only reply to me when I email,them, they seem to ignore me otherwise.

Even looking at this thread, it's been almost two weeks since responding.

Right now, I want to remove this unsupported equipment from my system, but I shouldn't have to bear the cost.

tw1l1ght wrote:
We have the same Case No, just noticed.

Has your unit ever reset the volume levels itself, or have you experienced really low muffled sound on system startup?

I've had the random pops also.

AidenL wrote:
Not that I noticed, so far it's been "only" random pops and the noise issue on channels 5+6.

@ AidenL ,

We've already answered few comments offline to your tech support emails offline so I'm not 100% sure if there is much to add here. I would hope that all the answers we provided would give you more information as to what happened to your file? We did test it, we did run some further script and did clarify all this information in the tech support ticket. Unfortunately, it's a bit hard for everybody to realize that "random events" (i.e. sometimes my level is low) isn't something that we can easily troubleshoot over a 1h test bench. If it was, we'd be more than happy to help. It requires for us to run a file over time and along multiple scripts doing powercycling/checking some random sequences.

"I've done all the basic troubleshooting, and have Dropboxed my project as requested on the 29th October and haven't heard a word back since."
While everybody here here has been very busy lately, we did received your file on a Friday afternoon (29th) and explained on the Nov 3rd of November that we would load the file which we did right away as our technician got some free time. Maybe you didn't receive that tech support ticket? Sorry to hear that.

As mentioned in our tech support ticket, we're behind our products and are more than happy to help! Sometimes a simple email suffice to know what's the progress on the testing. Since you've purchased your unit from a dealer, they would be able to help organize a replacement unit for you. That's a simple process.

Hoping all this info helps and sorry to read you're so upset about us. Just understand that we're here to help, just not within 24h over a week end period especially as sometimes it's much harder than it looks (i.e. completely random event)... Feel free to contact us or call us if you have further questions.

Devteam