Ron’s New System

[Ron Resnick]

The two small towers between the smaller bass traps are power amps IIRC.

yes

I am assuming, perhaps incorrectly, that they drive the woofer towers since the SETs are driving the panel speakers.

No. The VTLs drive the woofer ribbons in the Clarisys speakers.

If so, why are they so far from the towers?

They connect to the Clarisys crossovers.

I don't see the point in having them more forward, in the middle of the "soundstage." I also don't love having them right behind the panel speakers, either being vibrated by the woofer ribbons or disrupting the back wave of the woofer ribbons.

Where would you suggest I locate the VTLs?

Usually bass impact suffers with longer speaker cables, hence monoblocks to minimize that problem.

Both pairs of speaker cables I am using are 2 meters. This is shorter than the common 8 foot speaker cable length.

What is the crossover frequency to the main panels?

There is a high pass in front of the VTLs. There also is the crossover in front of each Clarisys speaker.

Which crossover frequency are you inquiring about?

Did you limit bass frequencies from entering your SETs? If yes, how has that been going?

I was, using the $29 Harrison Lab FMOD high pass filters. I concluded last week that I have been chasing my tail for months trying to troubleshoot edginess in the system (blaming the Italians) when I now believe it was these cheap high pass filters causing the edginess all along.

I ordered from Duelund four fancy capacitors targeting 2800pF. I picked as a pair the two which measured the closest.

Phil Marchand is inserting them into Cardas jumpers. I then will evaluate whether I gain more sonically by relieving the Italians of having to reproduce frequencies below 300 Hz than I lose in transparency by inserting a fancy capacitor in the signal path.

 

[Atmasphere]

I don't see the point in having them more forward, in the middle of the "soundstage." I also don't love having them right behind the panel speakers, either being vibrated by the woofer ribbons or disrupting the back wave of the woofer ribbons.

Where would you suggest I locate the VTLs?

If it were me I'd have them as close to the speaker terminals of the towers as possible. Two meters isn't bad unless the tower is 4 Ohms or less. The lower the impedance of the speaker the more critical the speaker cable becomes. A simple way to reduce that issue is to place the amp as near to the speaker as possible. I wouldn't be too concerned about vibrating it by the panel speakers, since they won't see that much sound pressure. As you know, if you are listening at the listening position and then get up and walk to either speaker, the sound pressure does not increase at all or only very slightly. So you can take advantage of that fact and place the woofer amps were its optimal.

I was, using the $29 Harrison Lab FMOD high pass filters. I concluded last week that I have been chasing my tail for months trying to troubleshoot edginess in the system (blaming the Italians) when I now believe it was these cheap high pass filters causing the edginess all along.

I ordered from Duelund four fancy capacitors targeting 2800pF. I picked as a pair the two which measured the closest.

Phil Marchand is inserting them into Cardas jumpers. I then will evaluate whether I gain more sonically by relieving the Italians of having to reproduce frequencies below 300 Hz than I lose in transparency by inserting a fancy capacitor in the signal path.

+1

 

[Ron Resnick]

Ralph,

Russtafarian kindly pointed out that you were asking about woofer towers, and I was answering about woofer ribbons.

Please see my edited and corrected replies.

 

[PeterA]

Ralph,

Russtafarian kindly pointed out that you were asking about woofer towers, and I was answering about woofer ribbons.

Please see my edited and corrected replies.

Ron, what are you using to drive the Pendragon woofer towers? It appears that you are using three sets of amps.

 

[Ron Resnick]

Ron, what are you using to drive the Pendragon woofer towers?

The built-in 1,000 watt Class AB Gryphon amplifiers.

 

[Atmasphere]

Ralph,

Russtafarian kindly pointed out that you were asking about woofer towers, and I was answering about woofer ribbons.

Please see my edited and corrected replies.

Right.

In that case if it were me I might move the VTLs to the rear of the Clarisys', positioned just so between the tweeter and woofer but otherwise as close to the speaker as I could get it, so as to reduce the speaker cable length. I'm likely being overly picky about such things, having had bad experiences with longer speaker cables. The sound pressure to which the amps would be exposed would not change.

Or I might just leave it all where it sits

 

[Holmz]

…


I was, using the $29 Harrison Lab FMOD high pass filters. I concluded last week that I have been chasing my tail for months trying to troubleshoot edginess in the system (blaming the Italians) when I now believe it was these cheap high pass filters causing the edginess all along.

I ordered from Duelund four fancy capacitors targeting 2800pF. I picked as a pair the two which measured the closest.

Phil Marchand is inserting them into Cardas jumpers. I then will evaluate whether I gain more sonically by relieving the Italians of having to reproduce frequencies below 300 Hz than I lose in transparency by inserting a fancy capacitor in the signal path.

I’m unsure about whether the Harrison are the issue, but it would be interesting to know how that was concluded.
And at that price, they certainly make it quicker and easier to hone in onto target frequencies that work or not.

However I sort of cheated on my approach to the identical problem.

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I ‘m not sure whether the battery biasing is needed, but it makes sense if there is hysteresis in the capacitor, which the biasing overcomes.
That seems like it would be the main possible causal mechanism for the Harrison Labs causing “The Italians” to complain.
But you sort of miss out on battery biasing with the Duelund’s in a jumper, but maybe those capacitors have less hysteresis than teflon ones?

300 Hz seems a but high, but if it works then that’s great.

 

[Atmasphere]

I ‘m not sure whether the battery biasing is needed, but it makes sense if there is hysteresis in the capacitor,

If a non-polar electrolytic is used, it certainly should be biased with a battery for best performance. I don't know of a non-polar electrolytic that provides a lead for this purpose and I've no doubt that the distortion that results from passing a signal thru such a thing has led to the bad rap electrolytics have.

But if you simply build up the desired value from two identical polarized caps, the lead in the middle where they are 'back to back' allows you to apply a biasing Voltage which allows the caps to be linear. This only works if the DC bias Voltage on the caps is greater than the audio signal which is has to pass. To do this you'd also need a network of resistors so the battery can be referenced. Its really easy to see why there are large value film caps now!

 

[Holmz]

If a non-polar electrolytic is used, it certainly should be biased with a battery for best performance. I don't know of a non-polar electrolytic that provides a lead for this purpose and I've no doubt that the distortion that results from passing a signal thru such a thing has led to the bad rap electrolytics have.

But if you simply build up the desired value from two identical polarized caps, the lead in the middle where they are 'back to back' allows you to apply a biasing Voltage which allows the caps to be linear. This only works if the DC bias Voltage on the caps is greater than the audio signal which is has to pass. To do this you'd also need a network of resistors so the battery can be referenced. Its really easy to see why there are large value film caps now!

Isn’t that dielectric hysterysis also some of the hypothesis behind the DBS biasing of the AQ cables?

 

[marty]

On this account, multiple subs are far more effective breaking up standing waves which are the number 1 problem with bass in most rooms. Once you have that sorted out then the bass traps will be found to be far more effective.

Ralph
This discussion, and your comments of the merits of multiple subwoofers, is sort of like watching the audio version of the movie "Hot Tub Time Machine'. This topic has been discussed many times in 2017, 20219 and many times since. Perhaps most importantly ("spoiler alert") there is no single answer or approach that will satisfy everybody.

The Geddes system, also known as a a multiple subwoofer swarm, is a method of neutralizing room resonances to optimize frequency response, not time alignment. If optimal frequency response is what you seek, that could be an effective approach. I am however, not a fan as time alignment suffers unacceptably. Depending on the crossover point chosen, the sonic anomalies of reproducing a bass or baritone male voice or the left hand of a piano or lower brass can be so temporally dysphoric that the illusion of reality is just unacceptable to me. Alternatively, the conventional subwoofer placement method commonly used, namely placing woofers several feet behind the mains, is a technique that many of have used (including myself), but time alignment? Fuggetabout it. This simply can't be done without dsp to retard the time arrival of the mains with respect to the subs. However, that doesn't mean that the sonic results using this subwoofer placement technique can't be sonically pleasing. It's a classic case of "not perfect" but perhaps "darn good", which is why some prefer this approach. This is why some experts, such as Barry Ober at JL Audio, defend it as a good choice nonetheless (details below). Unfortunately, this approach is also less than satisfactory for me regarding time alignment of the bass frequencies with respect to the arrival of sound coming from the mains particularly in the region immediately above crossover frequency of the subwoofers.

No need to re-invent the wheel but some posts which cover this topic in greater detail can be found here:

post #13

Time aligning subs to main speakers

I’m after some advice on how to think about t time aligning subwoofers to main speakers. Two papers that have informed my thinking are the http://www.acousticfrontiers.com/guide-to-bass-optimization/?utm_source=CTA and http://www.soundoctor.com/whitepapers/subs.htm. The latter puts forward a...

www.whatsbestforum.com

post #1732, 1735, 1736

Ron's Speaker, Turntable, Power and Room Treatment Upgrades

I was looking at those Funk subwoofers again. That is some awesome cabinetry skills.

www.whatsbestforum.com

 

[Audiohertz2]

Well Geddes did some reinventing of the wheel himself, much aplenty really , Ralph is a student of ……

Just saying.