TOPIC:

Hi,

I'm having trouble with my miniDSP/miniamp setup. I have single-sub sub/sat system. The L&R outputs are 1&2 respectively and the sub is 3&4. I have the sub in Stereo mode.

The left channel outputs to both the left sat and the sub, but the right channel only outputs to the satellite. There is apparently nothing from output 4. When I mute output4 in the software, it makes no difference to the sound. If I mute output 3, there is no signal from the sub at all.

I have two DSPs and two AMPs, so I was able to try them in every combination, and I get the same result. Therefore, I think I have something set up wrong. Can anyone help me to figure out what I've done? Is there a jumper,wiring or software setting that could cause this?

I thought that I had all the jumpers set up correctly based on the manual. The only one I wasn't quite sure about was the "I2S Routing Headers for selection of which I2S channel gets amplified" jumper for channels 3&4 on the amp (the bottom set). The manual says to set it to "sub out", but it's not clear which pins that refers to. I have it set to the default value of "I2S_Data_OUT_ch3&4" being the only closed jumper in the bottom set.

Thanks for your help.

Hello,

Not sure to understand the problem right but a couple of comments:
- In a Stereo sub configuration (4ch total), you're not in 2.1 mode (3ch). Agree? I'm therefore guessing that you're in a SE (single ended) 4x10W configuration on the miniAMP for that configuration to work and actually setup the plug-in to
"stereo mode"

- Please show a pic of your board so that we can see your jumper configuration. Easier than lots of words..

Thanks.

Thanks for getting back to me. I have three speakers total. The way that I understood it is that that the LF outputs would be summed and sent to the sub in BTL mode.


I can't seem to attach the photo. The output jumpers are setup with 1 and 2 (the two left ones) open. 3 and 4 (the right two) are closed.


Config1 is closed. Config2 is open (2.1 mode)

Thanks again

Ok, if you have 3 speakers, you don't have the subs in stereo mode but rather in "mono mode" (i.e. mixed to a mono channel we mean). So first step, make sure that your plug-in is configured correctly to Mono setting.

Your wiring seems correct apart from that so most likely down to the plug-in configuration.

Now, a warning, that settings in the 2.1 plug-in even in mono modes are not "copied" over.. I.e. you need to make sure that both channels have the same settings. Pay attention to the number (OUT 3&4) in the top section of each plug-in output to make sure that you're actually modifying the correct channel.

Hope this helps you troubleshoot.

Thanks! I have no idea how to do this. I'll search around, but if you can give me a hint where to look I'd appreciate it.

Jeremy

Okay, so I searched the forum and googled.

Do I need to change anything in the I2S header?

Do I just click the "Mono" mode radio button in the "sub output mode"?

If I do that, aren't outputs 1&2 mono now also? It sounds strange, and there's still no bass output when I mute output 3. I have 1&2 as the sats and 3&4 as the sub.

I guess what I want to know is, how do I get OUT4 (LF from right channel) to be summed in OUT3 (or does that happen automatically in the 2.1 mode?

Sorry for all the questions. I know I'm missing something simple here.

No jumper change should be required. Simply toggle the "Sub output mode" in the system settings to mono. What it will do is mix "input 1&2" (not outputs.., they are very much stereo) together to a single output for the BTL.

Please have a look at the 2.1 plug-in datasheet. It shows a diagram which should clarify a bit more the DSP path.

Hope this makes sense and sorry for the confusion...

DevTeam

Thanks for that. It's perfectly logical, and exactly how I thought it should work. It's just that when I do this, the sats don't seem to be in stereo. I have some left-only and right-only test tracks and they seem to go to both outputs 1&2 (sats) equally when in mono mode. By contrast, in stereo mode, there is great separation.

Are you certain that 1&2 are in stereo? Besides these test tracks, how do I prove my observation to you? (or prove that I'm wrong).

Sorry to keep bothering you with this, and thanks for your patient responses.

No worries, you're not bothering us.. We're just trying to understand the symptoms...

Not 100% sure but I think that the problem may be down to a typo of the user manual.. oops...
- Outputs 1&2 of the miniAMP are SE (single Ended). Meaning they are meant to go to the Satellites. If that's the case, the satellites are on I2S_Data_OUT_Ch3&4. So the first jumper for Outputs 1&2 should be on I2S_Data_OUT3&4 (not 1&2)
- Outputs 3 (BTL) for the mono Sub in 1x20 will be the mixed signal from the I2S_Data_OUT_Ch1&2 and should therefore be in that position for the Outputs3*4 position.

All this is documented in the updated user manual online on p4.
Have a try at it and I'm pretty sure that it'll solve the problem you're seeing.

Hope this helps,

DevTeam

Woah. Amazing what a little typo can do. It works now. Thanks! There's no way I would have figured that out. I had set up everything backward based on that figure in the miniAmp manual: I had my sats (the high-pass part of my crossover) on channels 1&2, and the sub (low-pass part of the crossover) on channels 3&4. To switch that seemed strange to me during the setup, but it was the only way that made sense with the jumper description.

Just so I really get it. What do you mean by "sub in 1x20" in the second bullet in your response to me?

Guys, this is just great. I've made and planned so many ASPs for various dipole and other systems, and I'm really looking forward to doing it with your DSPs now.

Glad it worked.
We meant SUB on 1x20W (BTL output) vs 2x10W (SE output) for the satellites)

Hope this helps and have fun,

DevTeam