# Question on MiniDSP filters and stacking



## hcanning (Oct 5, 2009)

Hi all,

I am having a lot of fun using my MiniDSP 2x4 to flatten the response of my sub! I just have a couple of questions.. I have a pretty serious peak to tame, as well as a far less serious but still correctable dip.

Is it going to cause any problems if I use two filters at the same frequency and bandwidth, one at -16db and the other 'stacked' to reduce by a further 4-5db, to achieve the desired cut on the peak? It obviously shows as desired in the MiniDSP plugin but I'm wondering if it'll cause any issues by going "out of spec" (more than -+16db) so to speak?

Also if I'm adding a boost of, say, 6-8db, and I'm looking at the input/output meters in the software whilst sending test tones, as long as there's no clipping showing in the meters (right into the red?) I'm OK and within the available headroom and shouldn't have any clipping/distortion, right?

Thanks!


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## Wayne A. Pflughaupt (Apr 13, 2006)

Technically it’s not a problem stacking filters. However, I have idea how things work with the miniDSP. I suppose if there is a problem, it’ll b something you’ll hear.

Can’t definitively answer the question about clipping, as (again) I don’t have a miniDSP. If you’re confident that the output meter reflects the addition of filters, then as long as you keep it well out of the red you’re fine. I say "well out of the red" because you want plenty of headroom should you ever use a source with a hotter signal than the one you were using as a reference for your post.

Regards,
Wayne


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## hcanning (Oct 5, 2009)

Wayne A. Pflughaupt said:


> Technically it’s not a problem stacking filters. However, I have idea how things work with the miniDSP. I suppose if there is a problem, it’ll b something you’ll hear.
> 
> Can’t definitively answer the question about clipping, as (again) I don’t have a miniDSP. If you’re confident that the output meter reflects the addition of filters, then as long as you keep it well out of the red you’re fine. I say "well out of the red" because you want plenty of headroom should you ever use a source with a hotter signal than the one you were using as a reference for your post.
> 
> ...


Thank you for your response Wayne. I guess my gut feelings were right. I'll have a play


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## hcanning (Oct 5, 2009)

After a morning of fiddling, here's my graph. I've been watching various clips to tweak the overall level, and just watched a full movie (Hacksaw Ridge, wow what a sound track) and it sounds impressive. There's no annoying boomy bass, just nice and deep and integrated nicely with the rest of the soundstage.










Edit: Purple is pre-calibration, but I guess that's obvious! I didn't want to go too mad boosting that null. I might even remove that filter completely and see if I can tell any difference. Unfortunately it wouldn't respond to moving the sub around in its immediate location and it's not really practical to put it anywhere else, so that's life!


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## andyr (May 27, 2011)

hcanning said:


> After a morning of fiddling, here's my graph. I've been watching various clips to tweak the overall level, and just watched a full movie (Hacksaw Ridge, wow what a sound track) and it sounds impressive. There's no annoying boomy bass, just nice and deep and integrated nicely with the rest of the soundstage.
> 
> 
> 
> ...


Excellent result, hcanning! :T

Would you mind telling me what miniDSP PEQ parameters you set, to tame that large peak around 45Hz?

Thanks,
Andy


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