Search found 14489 matches

by Nick
Thu Aug 11, 2022 12:31 pm
Forum: Assorted Stuff
Topic: General health matters.
Replies: 371
Views: 72082

Re: General health matters.

I had a similar situation a long time ago I don't think the two situations are equivalent. In Paul's case they had been sold something that they didn't need, and in fact didn't fix their problem. I would argue that Paul was "let go" because he didn't act in his employees interest. If he h...
by Nick
Thu Aug 11, 2022 11:15 am
Forum: Beginners
Topic: Statistical Regulator Without CCS?
Replies: 5
Views: 43

Re: Statistical Regulator Without CCS?

Yes I use vr’s but they’re a pain because of the few voltages available
Yes, but in this case 180v is just two 0b3's
by Nick
Thu Aug 11, 2022 9:03 am
Forum: Beginners
Topic: Statistical Regulator Without CCS?
Replies: 5
Views: 43

Re: Statistical Regulator Without CCS?

The statistical reg is effectively a zener diode. As such it will need to be driven by a load of some sort, either a resistor, or a current source. In both cases the load will have to be low enough such that the required current and shunt current is available (and the dissipation in the zeners is wi...
by Nick
Tue Aug 09, 2022 3:31 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

Maybe I am missing something, but my understanding of speaker harmonic distortion is that we only need to excite the fundamental. Then, just like with a musical instrument (or in this case a bell), all the harmonics are automatically excited. No crossover can change the behavior of the bell - only ...
by Nick
Mon Aug 08, 2022 11:16 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

May be the bell like sound of a penny dropping in the distance. The situation that is being described is such that the third harmonic (in this case) will not be directly excited because its above the xover frequency in use.
by Nick
Mon Aug 08, 2022 11:07 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

I think from what Scott is saying is that because the drive impedance is higher it restricts the motor from generating current in the voice coil at the frequency that is the third harmonic of the exciting frequency. And because the generation of current is reduced, the harmonic can not be generated ...
by Nick
Mon Aug 08, 2022 9:06 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

A change in inductance under dynamic loads, such as caused by a big uncontrolled bell-mode / resonance generates a [distortion] voltage source in series with the coil proportional to the magnitude of that change. By inserting a high impedance at that frequency, the less the current produced by that...
by Nick
Mon Aug 08, 2022 4:44 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

stamp out the bell mode with a high impedance notch, and it goes away. That's the bit I don't understand, how does a high impedance notch stamp out anything, surely a high impedance will reduce the damping on the motor, so if (for example) we excite the bell mode you are talking about with a extern...
by Nick
Mon Aug 08, 2022 4:36 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

It's both, since they're basically connected. In the sense that one caused the other yes, but if a caused b, that doesn't mean b causes a. AFAIK, Intermodulation is the result of non linear behavior when applied to two or more fundamental frequencies. What I thought you were talking about was harmo...
by Nick
Sun Aug 07, 2022 10:29 am
Forum: Everyones Projects
Topic: 6C33C SE-OTL Project
Replies: 155
Views: 70818

Re: 6C33C SE-OTL Project

My only concern would be the feedback. I would simulate it and see what happens.
by Nick
Sat Aug 06, 2022 8:50 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

What we're talking about is a manifestation of intermodulation distortion, am i correct ?
I don't think so. I think its the result of the non linear behavior of the moving mass under resonant conditions. But I may well be wrong.
by Nick
Fri Aug 05, 2022 8:52 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

Well, the two resonant frequencies will not be exactly the same as 0.22 * 4.2 != 0.15 * 6.2
by Nick
Fri Aug 05, 2022 8:11 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

I think you need the voltage source to be on series with the loudspeaker to model the effect the pdf is talking about.

I also think they will only look the same of you consider voltage in one case and current in the other.
by Nick
Fri Aug 05, 2022 6:25 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

I don't think a high driving impedance at 4.5kHz would rescue that.
Though (and just thinking out loud as its a interesting subject) maybe a parallel notch (across the driver) might by damping the motor at 4k5
by Nick
Fri Aug 05, 2022 3:38 pm
Forum: Speakers
Topic: Purifi-based monitor - options
Replies: 103
Views: 11166

Re: Purifi-based monitor - options

if the coil never receives the frequency in the first place, no distortion can be made.
I wonder of the mode could still be excited by a harmonic or undertone of the original frequency?