MiniDSP - Page 47

Nice! I plan on using the 10x10hd and doing something similar.

You should be able to copy inputs to the additional outputs using the built in matrix.

Similar.....lol

Absolutely! Here’s more on trying to boost nulls – should have linked it with my previous post.

Regards,
Wayne A. Pflughaupt

So it seems in the post quoted there was really no "myth" at all.

I saw the word "better", still looking for "never"...

Whether one should boost depends on the cause of the dip. Some dips cannot be corrected with a reasonable amount of boost while some can depending on the cause.

OK, I just took a measurement in my room. This is after MultiXT32. My sub is the PBultra 13 in a fairly small room. I have a balanced miniDSP 2x4 with the 2.1 advance plugin. Is it possible to make the valley around 55 a bit better using it? If so what steps should I try? Other than that the curve looks pretty good if I am doing everything right.

Can you move the sub's position at all?
If so, I would try that. Often it only take a small move.

You can add a little boost in the upper octaves, ala 55 Hz with minimal of damage since that is where the sub will have the most headroom to spare.
Edited by jpmst3 - 2/2/13 at 7:29am

Do i apply that on the input PEQ or the output? Or does it not matter as long as I bypass one?

You want to apply the EQ to the output you are using for your sub. That way if you add another down the road you can EQ it differently if necessary.

I plugged I made the changes, does it save automatically? I went to run my sweep in REW and now the sub is extremely quiet. Do I have to change the gains?

I am not sure on the details with the saving process. Perhaps someone else can chime in.

One cable from AVR to miniDSP is all that is required. The 10x10 has what's called "matrix routing," which means that any output can feed from any input (or any combination of inputs). Obviously, each amp channel needs its own signal cable from the miniDSP.

Do you know why my volume would be cut? I cannot get the sub to make any noise anymore. hmmmmm

No, it has to be something in your setup. Try removing all filters and start over adding one at a time.

It has to be something with my input voltage, it is measuring -72. That seems really low. If I put my sub trim to +12 I can get the miniDSP input voltage to read -40. Still way to quiet. I reset the miniDSP to factory defaults too.
Edited by Diesel 48 - 2/2/13 at 8:33am

Thanks Scott

Thanks!

Hopefully I'll be able to get if working without too much trouble then. Is there an option that I need to turn on for the outputs I assume? Wish there was a printed user manual with it.

What happens if you eliminate the miniDSP from the mix?

As soon as I take the miniDSP out of the chain my sub levels are normal again. My SPL meter reads roughly 70db. With the miniDSP hooked up it is nothing. The only way I could get the levels going to the miniDSP high enough were to go to levels, turn my receiver to +16db and then max out the subwoofer trim to +12. That would give the amp on the sub enough signal where I could crank the amp and hit 70db on my SPL meter. It seems like the miniDSP should not be cutting the signal that much.

Is there a gain on the input side of the miniDSP as well?

If not, you may need an Art Clean Box or some other type of booster gear.

You definitely don't want to run any component in the chain at full gain, especially the receiver. Full gain usually introduces more THD.

The only thing you can do on the miniDSP is cut the gain, not boost it.

Ahhh, well then I would imagine he has no choice but to boost the signal externally.
I was under the impression that the balanced version had more signal strength.

I am currently using the RCA out from my receiver. Maybe I should pick up an XLR cable and try the balanced output. Maybe that will give me the voltage I need.

The matrix screen in the software is pretty intuitive. Just click on the outputs you want to feed from a given input.

minidsp masters, this came up in the Rythmik subwoofers thread and I wanted to ask here.


How does the minidsp impact time alignment and phase? I really don't understand how EQ filters impact phase, any reading you all recommend?

One good read on the subject of how EQ affects system phase response can be found in the Minimum Phase section of the REW manual.

I couldn't quite tell what DonH50 was specifically referring to, but it looks like he was talking about the use of the miniDSP as an active crossover for a fully active loudspeaker. In that application, a difference in distance from each driver to the listener can be compensated by adding the appropriate delay to the driver or drivers closest to the listener. This might be useful in the case of a flush-mounted tweeter and a woofer whose effective acoustic center is somewhat behind the baffle because of the cone shape.

It sounds like what you're interested in though is an EQ application, is that right? If so, the information I linked above should help.
Edited by rock_bottom - 2/4/13 at 12:08pm

Thanks for the link. Yeah I believe you are correct that Don is more interested in full range / active crossovers but we'll let him chime in. I will just be EQ'ing my subs so not sure how concerned I should be with how minidsp filters (or PEQ filters in general) are hurting me (if at all), and if they are how do I make the situation better.

He's point about frequency vs time domain is interesting though. Audyssey and Antimode both claim time domain corrections. Is that possible with minidsp? I'm aware of the time delay, but is one overall time delay per channel really what is needed to compensate? I probably don't understand enough at this point to even ask the right questions, I'll read that link you provided.

That ends up being a somewhat complex question which I'll split into two.

First, there's the question of whether fixing up, say, a response peak with EQ will fix up the phase as well (which would also fix up the time domain quirks caused by that peak). The answer is that if e.g. the peak is in a minimum-phase region of the response, and the EQ is minimum-phase, flattening the response will indeed fix up the phase in the frequency region over which the EQ acts, which in turn will fix up (only) the time domain quirks caused by that specific peak (which you might verify with a waterfall plot). The filters in the miniDSP are of the minimum-phase type. The link shows how to determine whether the response region you're trying to EQ is minimum-phase or not.

The other issue is that most speakers, when considered over their full bandwidth, are not minimum-phase. This behavior causes time domain quirks in such speakers. Fixing up these kinds of quirks is done by so-called delay equalizers. The miniDSP does not do this. Not sure if Audyssey does, and I'm only aware of one audio product (by Thuneau) that actually does this, though there may be many more.