anti-sin(x)/(x) for NOS DAC via software parametric equalizer

[new2hifi]

Hi:

I am using JRiver Media Center software as server and player for feeding NOS filter-less DAC (TDA1541A based), Satch Tube Max from Diy HiFi Supply.

I want to experiment with parametric equalizer in JRiver Media Center to compensate for sin(x)/(x) high frequency loss.

Can someone please recommend me setting for doing it with parametric equalizer? Frequency, Bandwidth (Q), Gain? One filter or more than one...?

Regards

[abraxalito]

I haven't used JRiver but I did simulate an LC filter to do this on LTSpice. It needed a centre frequency around 28-30kHz I recall. Does your parametric equalizer go up to such high frequencies?

If not I know another way to do this - take a look at my blog : http://www.diyaudio.com/forums/blogs...orrection.html

[new2hifi]

Originally Posted by abraxalito

I haven't used JRiver but I did simulate an LC filter to do this on LTSpice. It needed a centre frequency around 28-30kHz I recall. Does your parametric equalizer go up to such high frequencies?...

Thanks for the input. I am just looking for settings for Frequency, Bandwidth (Q), Gain for filter or filters, no need to know the JRiver Media. JRiver can make any frequency filters.

I did saw the link you posted but I don't have any skills with filters. Thus, can you write me some settings that you got from Spice simulation?

[new2hifi]

Ok! I played with settings in JRiver and used following settings in parametric equalizer.

Center frequency: 20kHz
Gain: 3dB
Q: 0.12 (-3 dB at 2.37kHz and 169kHz)

I used the Analyzer in DSP on Pink Noise and it seems the parametric equalizer is correcting for high frequency loss. See the following pictures.






(I used 1-channel pink noise; no idea why Analyzer still showed two lines in graph)

Now the question is, if I am using parametric equalizer in DSP to adjust for high frequency loss, am I going back to crappy impulse response of digital filter?

I don't have equipment to measure impulse response. Thus, please help in answering this question.

Regards

[dddac]

My experience is, that every time you fiddle around with software, manipulating the sound track, spatial reproduction and low level detail is affected seriously.

why strive for bit perfect sound reproduction and start using a tone control?

If you really lack treble, you might want to consider to reduce a bit the damping of your tweeter in your loudspeaker?

[new2hifi]

Thanks for the input dddac!

My tweeters are already hot thus even with NOS DAC I never felt the need for more treble. However, I am really curious if this method works or does it take us back to ringing impulse response of linear phase filters.

Hey.....everyone, please give us your input.

[abraxalito]

Originally Posted by new2hifi

I did saw the link you posted but I don't have any skills with filters. Thus, can you write me some settings that you got from Spice simulation?

Just noticed I didn't reply to this earlier - Spice simulation doesn't have 'settings' that would be meaningful to someone who's not comfortable with circuit simulations.

You asked whether parametric equalisation takes us to ringing - and of course the answer is 'yes, it does'. All FR changes will have effects on the time domain. The difference is that almost all digital fitlers have pre-ringing because they're designed to be linear phase. The parametric EQ won't have this artifact so could sound better - parametric EQs are usually minimum phase so just exhibit post-ringing.

[new2hifi]

Thanks abraxalito!

I appreciate your response and breaking the bad news (post ringing) to me or to others if they did not know that already.

Hum ..........so there is no free lunch in digital too.

[abraxalito]

Funny you should talk about a 'free lunch' - I think there might just be one in terms of SQ. That's to filter the output rather more aggressively than is customary. I've been listening to my DAC through an elliptic filter and its made a really substantial improvement But then I'm not using a TDA1541A so perhaps its just brought my listening experience up to the level yours always was

[regal]

VST Plugin Izotope Ozone has a minimum phase setting for parametric EQ which should prevent most of the pre-ringing






Foobar works well with VST plugins. I always come back to it. Just wish it had a good SRC