Hmmm, that's unfortunate. Since Sigma Studio has an FIR filter could one just use that to correct phase?
Last edited:
I'd suggest not trying to correct phase, but just using linear phase xovers for a good start, if they are available. Complementary would be best.
Alright, what would you say is the steepest linear phase filter that I can get on there? I'm looking for steep because I'm looking to push this celestion and another compression driver as low as I can.
That comes down to the dsp capability of what you are using.
Which means how many taps of FIR are available at what sampling rate.
I know nothing about Sigma...
but tell me what xover frequency and order you want, and i'll give a stab at predicting how many taps you need.
Which means how many taps of FIR are available at what sampling rate.
I know nothing about Sigma...
but tell me what xover frequency and order you want, and i'll give a stab at predicting how many taps you need.
Ideally I'd like 1400hz at 24db per octave. I was looking through the manual earlier, I'll try and get that information for you. It's a pretty powerful chip.
Edit: 3000 double precision biquad filters or 24,000 FIR filter taps per sample at 48 kHz audio sampling rate.
More importantly is when I'll be using this for an XO around 1100hz at 24db per octave (or steeper) in the next project.
Edit: 3000 double precision biquad filters or 24,000 FIR filter taps per sample at 48 kHz audio sampling rate.
More importantly is when I'll be using this for an XO around 1100hz at 24db per octave (or steeper) in the next project.
Last edited:
24,000 taps @ 48kHz is hugely powerful. Haven't heard of that much power in a chip...unless it's maybe all resources applied to a single channel spec.
Please link me to further info.
1400Hz at 24dB/oct needs no more than maybe 200 taps.
fwiw, 24dB/oct is not steep at all, imo...
Last edited:
Cool. Powerful for sure.
You should have no problem impementing however steep you wish, brickwall included, at 1400Hz.
What you're working with is beyond my technical knowledge, but I do believe the tap count listed is an all out single channel spec.
Without more info, I'd divide the 24,000 by however many channels you need, to get an available tap count per channel
You should have no problem impementing however steep you wish, brickwall included, at 1400Hz.
What you're working with is beyond my technical knowledge, but I do believe the tap count listed is an all out single channel spec.
Without more info, I'd divide the 24,000 by however many channels you need, to get an available tap count per channel
The usual workaround for the warping of the frequency axis with bilinear transform is the use of a higher sampling rate.
Regards
Charles
Regards
Charles
Not yet. I accidently wrecked my 3e DSP after completing the SigmaStudio project, but before I could take measurements and listen. Then the new board was back ordered for several months (sigh), but a new one is on the way. I'm anxious to compare the Harsch implementation against a previously completed LR4 design for the same speakers.
Ernperkins,
Sorry to hear about your 3E amp, if you are in the market for a new TPA3255, there is a GB for a RTR TPA3255 with PFFB enabled that just started. I’m using the TPA3255 to drive a passive Harsch XO with the PTT6.5 and RS28F in a waveguide. I also have Sigma Studio and have developed a custom 8ch ADAU1452 with nice quality AKM ADCs and DACs. Still working on getting the DAC to work right though. Making a DSP from scratch is a lot of work. 🙂
Sorry to hear about your 3E amp, if you are in the market for a new TPA3255, there is a GB for a RTR TPA3255 with PFFB enabled that just started. I’m using the TPA3255 to drive a passive Harsch XO with the PTT6.5 and RS28F in a waveguide. I also have Sigma Studio and have developed a custom 8ch ADAU1452 with nice quality AKM ADCs and DACs. Still working on getting the DAC to work right though. Making a DSP from scratch is a lot of work. 🙂