rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool

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#1,084
pos said:
You have to make sure you do not hit 0dBFS line anywhere in area where calculations or data transmission are not handle in floats.
Keeping a 6dB margin is a good practice.

Why are you using Jriver's PEQ instead of doing them within the convolution?
Click to expand...

Pos, do you mean specify the scaling in the convolution config file? I could do that. Any advantage of doing it that way?
 
#1,086
wesayso said:
This sentence above might explain that, as long as the PEQ's are not boosting...

Are they?
Click to expand...

Thats what i was thinking.
But there is a confusing option menu where you can specify each object in the chain to be independent of the internal volume. Not yet clear what thats doing.

With everything disabled in the DSP stack i still see the -10db different on the pink noise. Something is amiss, havent found it yet
 
#1,088
jojip said:
Strange thing is the internal volume slider doesnt seem to make a difference to the level displayed on the analyzer
Click to expand...

Just tried this in my setup by playing a random song and looking at the analyzer. It perfectly lines up with the internal volume control, drop the volume and the graph in Analyzer drops as well. I guess we'd need to see more settings to get this sorted out. It would be strange (to me) to drop internal volume by 12 dB only to later raise that volume level in another DSP section by 9 dB.
Something is off here... Could you make a screen-grab of the Options -> Audio that includes the volume settings?
 
#1,090
Isn't this one doing exactly what you want?

What you show here is a left channel -20 dB signal source playing and in the analyzer it is showing -19.8 dB for that left channel. With the internal volume set at 100% it all seems to fit rather well. A leak signal is seen in the right channel of -96.5 dB. The rest of them are silent.

Not sure what is wrong here, seems quite alright to me.
 
#1,092
Hello,
I'm using audioweaver to prosess FIR filters like this for example:
http://www.diyaudio.com/forums/digi...ery-audioweaver-anyone-tried.html#post4522868 post #6 and #7.

I want tha holy grail of high frequency resolution and low latency, but struggle🙂

I have tried a lot with rephase, setting long FIRs eg many taps (65536) and about 20ms centering. The frequency resolution will not go up. It's actually better results with 2048 taps and centering: middle.

Do anyone know settings that enable high frequency resolution and low latency e.g. that has not to have symetric impulse response?
Any linking to litterature is also appretiated.
I'm looking for https://eilex.com/vir-filter/ functionality in freeware.....


Regards Torgeir
 
#1,093
hi all,

i have an UMIK-1 & experiencing with REW software. i detected a phase problem regarding my subwoofer and tried rePhase.

however, failed to get a result; because i do not have enough knowledge regarding measurement & optimization, phase, magnitude, impedance, etc.

can you suggest me relevant books for gaining a proper background and an insight for acoustics?
 
#1,094
Is this where I should ask? In rephase, I cannot see any FR plotted after I "import" a measurement from REW, I just see the phase plotted. I tried following here: https://www.minidsp.com/applications/advanced-tools/rephase-fir-tool

Any suggestions? Should I make a new thread instead, or could someone point me to where this discussion has been gone over previously? (I didn't find)

Here is what I see in rePhase and in REW:
 

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#1,095
critofur said:
.....In rephase, I cannot see any FR plotted after I "import" a measurement from REW.....
Click to expand...

Looks in your REW plot measured frq response dynamic range is within +47dB to +77dB and into Rephase visible range is set to -30dB to +20dB. In Rephase at "Ranges" tab you can change the scale so frq trace get visible or into REW before export then offset measurement to zero dB area.
 
#1,096
Yes, you can use the "gain offset" setting in the measurement import tab.
The array keys will let you quickly lower the value until the magnitude graph becomes visible.

When your finished with your correction don't forget to use the bypass button to make sure correction levels are in check.
 
#1,097
phantom4 said:
hi all,

i have an UMIK-1 & experiencing with REW software. i detected a phase problem regarding my subwoofer and tried rePhase.

however, failed to get a result; because i do not have enough knowledge regarding measurement & optimization, phase, magnitude, impedance, etc.

can you suggest me relevant books for gaining a proper background and an insight for acoustics?
Click to expand...

Hello,

This is a question that goes far beyond the scope of this topic 😛

The most difficult (and rewarding) part is getting a good main/sub integration using your crossover (IIR or FIR).
When this is done, phase linearization is pretty easy to do.

By the way, what it is that you want to linearize the phase of?
Is it the main/sub crossover, or the high pass of the sub?
 
#1,098
Hopefully my question is sufficiently on-topic 😱.

I really love how FIR filtering can turn a multi-way loudspeaker into a minimum-phase system. The first time I looked at step response of a 2-way with steep filters and linearized phase, I was truly baffled. What I do not like to see though, is pre-ringing. As far as I know, if you ever depart from minimum-phase, there is no way to move back to minimum-phase without adding pre-ringing. Is this right?
 
#1,099
pos said:
Hello,

This is a question that goes far beyond the scope of this topic 😛

The most difficult (and rewarding) part is getting a good main/sub integration using your crossover (IIR or FIR).
When this is done, phase linearization is pretty easy to do.

By the way, what it is that you want to linearize the phase of?
Is it the main/sub crossover, or the high pass of the sub?
Click to expand...

my subw's design is isobaric, working bandpass. inside the band, there is a huge dip around 54Hz (central freq). same dip exists in main speakers. subw signal is being cut on my subw amp (LPF ~100Hz).

same dip exists in the measurement of main speakers.

after having computed excess group delay, GD chart of REW indicates a peak in group delay as ~90ms right at 68Hz (central freq).

i would like to deploy rePhase, however does not have enough knowledge. i cannot determine the cause of the problem; is it due room mode, is it just a simple magnitude problem that can be smoothed out with EQ? actually, i am confused.

that is why i am asking for solid books to gain a solid understanding of hifi system - environment relationship.
 
#1,100
keyser said:
Hopefully my question is sufficiently on-topic 😱.

I really love how FIR filtering can turn a multi-way loudspeaker into a minimum-phase system. The first time I looked at step response of a 2-way with steep filters and linearized phase, I was truly baffled. What I do not like to see though, is pre-ringing. As far as I know, if you ever depart from minimum-phase, there is no way to move back to minimum-phase without adding pre-ringing. Is this right?
Click to expand...

If your target is a minimum phase response (ie you don't linearize the phase of the system's high/low pass) and your crossover are summing properly in a large enough angle, then you should not get any pre ringing.
Most DAC use linear phase antialiasing filters so you will get pre ringing there, but this is supposed to be outside of the audible range.

Regarding your question, yes using FIR you can turn a linear phase system back to minimum phase just as like you can turn it linear phase in the first place.
With careful measurements you can even make the linear phase anti aliasing filter of your DAC minimu phase, basically by adding allpass filters, and it will eventually remove any pre ringing you might have there.
 
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