New DIY Mid High

Jul 31, 2017
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First time really listening using the basic IIR filters Peter posted here

Sounds wonderful. Love the clarity on the high end and how the further away you get, the only thing that changes is volume, stays very sharp.

I'm on the very beginning of the learning curve when it comes to processing, so looking forward to making them sound even better.



@Peter Morris - I pm'ed you about your latest FIR filters, but here is probably better. I read through this thread and the 60 degree thread again, but the only filters I am seeing are these.

1. Sounds like there are newer ones? Are they posted somewhere and I'm missing it?

2. For someone new like me, where should I be getting started when it comes to doing my own measurements? This thread has been super informative, enjoying learning from you all.
 
Jul 31, 2017
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What are you housing for processing and amplification?
Q-sys 110f to QSC cxd4.5Q network amps + speakerpower plate amps for my subs.

The q-sys can do full fir via coefficient csv / wav import.

It's pretty cool software, you build out your routing first, dropping in all the items you'd like into your process, then take that design and set it up.




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I tried to do copying Peter's settings here, using RePhase to export the FIR crossovers and the raised cosine filters. Haven't gotten a chance to listen yet and they are probably wrong.

Also still trying to figure out how to phase align the subs.

I've been bugging Peter for help, but any other advice would be wonderful. Learning a lot!
 
Feb 24, 2015
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Q-sys 110f to QSC cxd4.5Q network amps + speakerpower plate amps for my subs.

The q-sys can do full fir via coefficient csv / wav import.

It's pretty cool software, you build out your routing first, dropping in all the items you'd like into your process, then take that design and set it up.



I tried to do copying Peter's settings here, using RePhase to export the FIR crossovers and the raised cosine filters. Haven't gotten a chance to listen yet and they are probably wrong.

Also still trying to figure out how to phase align the subs.

I've been bugging Peter for help, but any other advice would be wonderful. Learning a lot!

Hi Ti, Very nice work.

The q-sys looks very capable. How many taps, at what sample rates, can it handle?

One trick I've learned for aligning subs, when using linear-phase crossovers, is to find the sub's delay with everything in play other than the FIR filter. This usually gives a dead-on repeatable time. Then turn the FIR filter on, which has a known # of samples delay, add that delay to the previous measurement, and you get a specific delay that ties linear-phase together pretty perfectly. Delay finder times will group very closely around that total time, the more linear the phase of the sub and main through the crossover region, the tighter the grouping will be.

Of course, if you are using IIR between sub and the DIY you will have to go through the 'phase trace overlay method'. Which can be a little confusing at start because of inconsistent delay time readings for the sub.

I'd recommend to anyone who has the FIR capability to first learn to tie things together with linear-phase, because it becomes trivially easy with a little experience. It is also good preliminary training for moving to IIR and the phase trace overlay method , for when the FIR latency is too much for the application..

FWIW :)
 
Jul 31, 2017
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Hi Ti, Very nice work.

The q-sys looks very capable. How many taps, at what sample rates, can it handle?

One trick I've learned for aligning subs, when using linear-phase crossovers, is to find the sub's delay with everything in play other than the FIR filter. This usually gives a dead-on repeatable time. Then turn the FIR filter on, which has a known # of samples delay, add that delay to the previous measurement, and you get a specific delay that ties linear-phase together pretty perfectly. Delay finder times will group very closely around that total time, the more linear the phase of the sub and main through the crossover region, the tighter the grouping will be.

Of course, if you are using IIR between sub and the DIY you will have to go through the 'phase trace overlay method'. Which can be a little confusing at start because of inconsistent delay time readings for the sub.

I'd recommend to anyone who has the FIR capability to first learn to tie things together with linear-phase, because it becomes trivially easy with a little experience. It is also good preliminary training for moving to IIR and the phase trace overlay method , for when the FIR latency is too much for the application..

FWIW :)
Thanks Mark!

4096 taps @ 48khz.

I've watched some videos on the "phase trace overlay method". Went ahead and downloaded a trial of Smaart and can use the Q-sys as a USB soundcard. I've gotten that working, but haven't run measurements yet. Hopefully this evening.

With the mid hi's, Peter kindly sent over his latest FIR settings and I directly copied them from the Lake Controller. His approach of using FIR linear-phase filters for all the crossovers except the sub make sense to me. I will try to replicate that.

I'll post some measurements shortly and perhaps you can steer me in the right direction.

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As a promise to this thread, I'll also post some additional drawings of the mid-hi. Max get's most of the credit, since I will use his as a baseline, but with some modifications now that I've actually built two pairs.

Will do two versions, one for people building without a CNC with exact measurements of each part of the horn path so you can easily trace it out + part dimensions + cutsheets.

Then a second version for CNC users that you should be able to directly import into your CAM tool and define your toolpaths. Will color code it so it's super easy, EG: Red paths = outside throughcut ---- Green paths = 6mm deep pocket etc.
 
May 8, 2011
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Hi Ti,

What I have been doing for the sub crossover is to use an IIR to keep the latency acceptable for FOH application. I think typically you can get away with 10 ms (or more) as the loud backline instruments are usually at least this distance in time behind the FOH speakers.

I then use the ‘phase trace overlay method' to match the two phase traces often adding and additional all-pass filter to the sub to get every thing to match perfectly.

When adding all-pass filters to various pass bands you have be mindful of the resulting signal polarity, sometimes you may end up flipping it to get every thing to line up correctly.
 
Likes: Ti Liptak
Feb 20, 2013
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Richmond, VA
Hi Jaroslav,

They look great, love your build quality - I hope you have great success with these boxes.

Best Regards

Peter
Thank you for the positive feedback I've been using boxes since June 2018 and the listeners and musicians are happy and amazed how it is possible that such a small box so nicely and so loudly plays :)
Once again thanks to Peter for this design.
Jarda Mike