Yes indeed... Cut through the hype to see if they are actually any good... And what they really do if you're not peeking.
Hmm.. One page of almost useless info - not enough data about how they measured it, for a start... Measured only at a low level,poor choice of input (they had to ADC an analog source rather than using a digital source)... Hmm...
All BM s in the 80 s did it this way with TW and SUperTWs.
In the end, they replaced some problems with other ones. They sounded very clear but extreme bright imho.( But who cares. Nowadays they created new problems for their perfect solutions.)
Similar for their woofers which had coil/magnet sensors, going very low but no bass.
Maybe it was the MR causing the problems, had also inductive sensors and prominent sound. They called it precision. We had another name therefor. 😀
The woofers became also the problem to run over their mechanical limits, i will never forget this nightmare in my servicejob in those days.
I remember also Serviceguys for the Infinity servostatic, it was said , all of them had black arms due some specific problems therewith.
I sold such a system to an autosound company about 35 years ago,
and it works pretty well, assuming that it is for woofer use. Requires
some EQ, as the feedback aims toward velocity rather than the usual
acceleration model.
🙂 😎
Yes, it works well on the bass and for low freq extension in small volumes and still with relatively low distortion it is good way to go.... but it adds extra cost and complexity. So, this approach isnt for the low end of the crowd.
In my case, small volume/size isnt a concern. This is for the high-end crowd. So, a little complexity and cost is less a factor. I want greater accuracy and that includes lower distortion. Starting with good drivers to begin with for the purpose. I will use a sealed/closed box for a sub only application. And using the PA portion of the Crown amps (2500W per channel 😱) but lowering the distortion can be done in several ways - electronically. There are hard ways and easy ways and in-between ways.
I would like the simplest ways that get me 50% or more reduction in distortion. MFB and DVC are in the running due to ease of application and might make a great project for DIY'er also.
So far, my simple added Re MFB approach is about as simple as it gets and provides significant results. Plus, all DIY'ers can mod their amps to do it in a short time and at lowest cost. I happen to have DVC drivers, so that adds a second - middle or in-between complexity solution.
THx-RNMarsh
Last edited:
Are there many high end DVC drivers to choose from though? They are common in car audio....but....
Rythmik Audio F12SE Subwoofer These guys are indeed on to something. Review By Clarke Robinson
Rythmik Audio • Servo subwoofer testimonials and reviews
There's another brand or two somewhere. GR-Research does an OB version that's more musical.
I was modding their amplifiers for people for awhile, which gave them even more articulation. But I haven't been able to compare a modded one vs. a Funk subwoofer that a guy I know with decent tastes, says is better. The Funk uses DSP and massive drivers with probably a shitload of mechanical brakes, which is why they have thousands of watts from classD. However replacing JL Gothoms with servos is something that happens.
On the contrary, i found this idea to compare the response curves at different SPL levels, interesting.
Last edited:
My point is, any energy that enters the listening space must come from the cone, otherwise a cone position system does not reflect what we hear.
Tapped horns actually present more energy via the back of the woofer, the combined energy cannot entirely be controlled coherently.
Heck, it's so much easier to fix the BL non linearity mechanically in the magnetic circuit. I'm surprised nobody has done that yet.
Jn
I'm surprised at this because I don't see anything new here. Heck Peavey has mfg these for ages. McCauley has had them for a long time too.
I'd test my Focal drivers but the rubber surrounds disintegrated into nothing ness.
It's good all good stuff.
Cheers,
The Funk, as in Dave Funk the physicist and amp designer/builder?
Also, Wilson has a sub with a servo in it. Either 18 inch or 21 inch, both?
Wilson doesn't service them any longer so someone might be able to pick one up "cheap" and do a look see and re-design with modern parts.
They were pretty high dollar items, if I recall.
Here is a review LINK
Cheers
Also, Wilson has a sub with a servo in it. Either 18 inch or 21 inch, both?
Wilson doesn't service them any longer so someone might be able to pick one up "cheap" and do a look see and re-design with modern parts.
They were pretty high dollar items, if I recall.
Here is a review LINK
Cheers
Last edited:
Speakers are interesting, but I just happened upon a piece of TI applications information that reads as follows:
"In listening tests at TI's sound room evaluating different circuit components used in the LM4702 demo amplifier, there was one part whose negative effect on audible signal quality was undeniable. A DC blocking capacitor on the input of the LM4702 degraded sound quality. In multiple listening tests, with different participants and at various locations around the country, the negative effects of even the best film and foil polystyrene DC blocking input capacitors in the audio signal path was confirmed. It is therefore recommended that DC blocking capacitors not be used in the signal path for mid to high-end audio equipment. Where DC offset from another signal source may be a problem then the use of a DC servo circuit that keeps DC offset from appearing at the output of the amplifier is recommended."
This is the document that contained the above information: http://www.ti.com/lit/an/snaa031a/snaa031a.pdf
"In listening tests at TI's sound room evaluating different circuit components used in the LM4702 demo amplifier, there was one part whose negative effect on audible signal quality was undeniable. A DC blocking capacitor on the input of the LM4702 degraded sound quality. In multiple listening tests, with different participants and at various locations around the country, the negative effects of even the best film and foil polystyrene DC blocking input capacitors in the audio signal path was confirmed. It is therefore recommended that DC blocking capacitors not be used in the signal path for mid to high-end audio equipment. Where DC offset from another signal source may be a problem then the use of a DC servo circuit that keeps DC offset from appearing at the output of the amplifier is recommended."
This is the document that contained the above information: http://www.ti.com/lit/an/snaa031a/snaa031a.pdf
Pretty sure TI doesn't even have a listening room. Now I 'think' this was a natsemi part. Not sure they did either, BUT both companies did have a number of audiophiles...
- Status
- Not open for further replies.