By-passing speaker's passive crossover for DSP crossover - need to insert capacitor/s?

[hollis]

....DSP crossover in place ?

How did your project go?

 

[dualazmak]

Hello friends,

Now I found and believe this thread is the best place to ask my "not yet fully answered and understood" naive inquiry.

In my multichannel multi-amplifier project, I have already fully bypassed/eliminated the passive LC crossover.
(I still have the protection capacitors for Mid Be-dome, Be-tweeter and super-tweeter as shared in my above post #59.)

My another inquiry here is related to my experience in how I could bypass/eliminate the attenuators which have been sitting after the LC crossover just before the SP drivers.

I would highly appreciate if you could carefully review my post here entitled "Further Insights on SP Attenuators and their Elimination in Multichannel System" and the post here, for the details of my experience. As shared there, I found that, at least in my specific system, replacement of the attenuators with 20 - 22 Ohm resistors gave most preferable total sound quality (or sound quality preservation).

On the other hand, the simple bypass/elimination of the attenuators from the circuit somewhat slightly deteriorated the sound quality in the system with Yamaha NS-1000's Mid Be-tweeter, Be-tweeter and outer super-tweeter Fostex T925A.

Can "the subjectively favorable effect of these 20-25 Ohm parallel resistors" (i.e. a small constant and extra power load to amps) be explained and/or justified in terms of the zero-cross distortions in the amps? I myself am very questionable about this since almost all the modern Hi-Fi solid-state amps have no or negligible audible zero-cross distortions...

Any of your idea and/or speculations validating my above experience of replacing the attenuators with fixed parallel resistors will be highly appreciated.

 

[Music1969]

How did your project go?

Hi, it actually turned out great.

I bought the recommended capacitors for tweeters but haven't gotten around to soldering them in-line.

I spend a couple minutes before any listening session making sure the DSP crossover is properly active before every listening session - to make sure the tweeter doesn't woof.

I also make sure to power on and power off all electronics with the correct sequence. Amp/s on last and amp/s off first.

And I start music playing at ultra low volume and gradually increase - listening for anything unusual in sound (eg maybe DSP crossover isn't active).

Eventually I should get around to installing those caps but so far (some months now) no issues.

This was done with a very old speaker. Moreso for learning purposes.

I started a new thread about doing this with a newer and "better" speaker, under US$800

https://www.audiosciencereview.com/...-convert-to-active-under-us-800-a-pair.20890/

In a couple years, I want to pickup a used KEF R3 at a good price but I have much more learning to do first.

 

[hollis]

Hello friends,
Any of your idea and/or speculations validating my above experience of replacing the attenuators with fixed parallel resistors will be highly appreciated.

Hi Friend!

Good news and bad news. I love your thread, and I have it saved to read from the beginning. I am 100% DSP for my 4-way stereo rig though, zero attenuators for me.

 

[dualazmak]

Hi Friend!

Good news and bad news. I love your thread, and I have it saved to read from the beginning. I am 100% DSP for my 4-way stereo rig though, zero attenuators for me.

Well, do you recognize that the 20-22 Ohm fixed resistors I have in replacement of the attenuators "in parallel with the SP drivers" are still a kind of "attenuator"?? I assume they are not the pure attenuator but are just fine tuning chips/resistors for better sound quality since no sound "volume attenuation" are given by these parallel resistors as you can see them in the circuit...

If the total impedance of the SP circuits would somewhat affect or important to preserve the magical sound quality and balance of NS-1000 (and T925A), then may we still recognize the resistor as a kind of "attenuator" (not variable but fixed attenuator)? Looking from the amplifier, the parallel 22 Ohm resistor would be just an extra power consumer...

 

[hollis]

Sadly I do not understand circuits or resistors all that well. Why do you want to use attenuators instead of dropping the DSP level you send out of the multi ch D/A?

 

[dualazmak]

Sadly I do not understand circuits or resistors all that well. Why do you want to use attenuators instead of dropping the DSP level you send out of the multi ch D/A?

Thank you for your interest but looks you do not understand my point...
You need to carefully look at and understand the circuits in my post here and here.

I fully bypassed/eliminated the attenuator, but the 22 Ohm resistor "in parallel with SP driver" gives best sound quality... As you indicated, I am now fully utilizing the digital software DSP for attenuations.

The 22 Ohm resistors are just for fine tuning of the total sound quality based on my actual empirical experiments. I would like to know some theoretical or engineering reason or validation for that...

 

[dualazmak]

Hi, it actually turned out great.
....
I also make sure to power on and power off all electronics with the correct sequence. Amp/s on last and amp/s off first.
....
And I start music playing at ultra low volume and gradually increase - listening for anything unusual in sound (eg maybe DSP crossover isn't active).
....

Hello Music1969,

Nice to hear so since I am also much careful about "Shutdown Sequence" and "Startup (Ignition) Sequence" in my (provisionally) completed multichannel multi-amplifier system, as shared here entitled "Startup (Ignition) Sequence and Shutdown Sequence of the Multichannel Multi-amplifier System", for your interest and reference.

Please note that I am using three "integrated" amps, Accuphase E-460, Yamaha A-S3000 and Sony TA-A1ES, with all of their volume controllers active.