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.

Vandersteen Audio High End Speakers | Vandersteen Audio

Vandersteen Audio High End Speakers

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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.

 

[Atmasphere]

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

Might be. If the preamp has a very low output impedance that would be a small concern as the impedance will swamp the effects of capacitance in the cable.

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.

At 80Hz the waveform is 14 feet long. The waveform must pass by the ear completely for the ear to know its there. It takes a few more iterations to know what the note actually is.

Imagine the problem of a note at 40Hz with a 28 foot length.

This means in most rooms unless quite large, a note at that frequency will have bounced around the room several times before your ear can identify the note. Therefore below about 80Hz in most rooms, the bass is 100% reverberant. It is harmonics of the note from the main speakers that let you know where the sound came from. As long as the subs do not make energy above about 80Hz, they will not attract the ear's attention.

On that account, time alignment simply isn't a thing. But if the subs are active much higher, it certainly is!

 

[Audiohertz2]

Imagine if it’s an after the fact servo controlled correction sub ..!

Spirit Airlines …

 

[marty]

Might be. If the preamp has a very low output impedance that would be a small concern as the impedance will swamp the effects of capacitance in the cable.

At 80Hz the waveform is 14 feet long. The waveform must pass by the ear completely for the ear to know its there. It takes a few more iterations to know what the note actually is.

Imagine the problem of a note at 40Hz with a 28 foot length.

This means in most rooms unless quite large, a note at that frequency will have bounced around the room several times before your ear can identify the note. Therefore below about 80Hz in most rooms, the bass is 100% reverberant. It is harmonics of the note from the main speakers that let you know where the sound came from. As long as the subs do not make energy above about 80Hz, they will not attract the ear's attention.

On that account, time alignment simply isn't a thing. But if the subs are active much higher, it certainly is!

Agree to disagree Ralph. When I listen to reproduced orchestral music that contains bass below 60 and the system is not time aligned the vagaries of instrument location can differ from note to note. For example D1= 37Hz; F1 = 43Hz; A1 = 55Hz, C2=65Hz E2= 82 Hz. Depending on your crossover point, the localization of these notes will be distributed proportionally between the sub and the mains. If your sub is placed at a different location from the mains, the sound you hear will be localized accordingly depending on the note. The same instrument will appear to eminate from different locations depending on the note played. That is not what the microphone hears. The old adage that bass is not localized is totally fallacious. Anyone who attends classical concerts can easily point with one finger and their eyes closed to the source of an instrument with significant bass radiation such as a tympani, tuba, or single double bass from anywhere they sit.

The reason the famous Sheffield drum track is such a valuable evaluation tool is that the recording engineers (as stated in published interviews) were obsessed with reproducing both <30-40Hz bass fundamentals of the kick drum as well as the 90-120Hz components of the upper bass from the kick drum and the floor tom tom. A reproduction system that is truly time aligned will make Jim Keltner's trap set sound like mush a far as localization. Swarm subs make such reproduction sound completely unacceptable to me, event though the overall frequency response is "smooth". Again, what one prioritizes in your home reproduction system is simply personal preference. But accurate time alignment of the subs to mains is just something I cannot live without. It is the reason IMHO why most subs are not as sonically successful as they might be with more stringent set-up. Impulse measurements can be extremely valuable in facilitating such alignment. Unfortunately, such tools are not commonly used by audiophiles.

 

[Mike Lavigne]

with my twin tower EA MM7's which are time aligned, i have the 86" tall active sealed box bass towers (-4- 15" stacked under 35hz) and the 4 passive 11" mid woofers 25hz-250hz (in the main towers) all equa-distant from my listening position for a synchronized wave launch. i get very locked in, explosive and cohesive bass. my room is large enough to allow for the lowest octaves. my imaging is full range (of the bass that is directional), the bass is of a piece with the images.

no significant dips or humps in the FR curve. i did have a big 10db suck out at 30hz until i closed up my ceiling bass trap in 2015.

i'll leave the finer technical stuff to you guys. but i like the idea of time alignment when you can do it (not every room is wide enough). the bass towers of the MM7's can be placed anywhere in the room, but are best kept time aligned.

 

[Ron Resnick]

I am enjoying this Ralph/Marty debate!

 

[pjwd]

Agree to disagree Ralph. When I listen to reproduced orchestral music that contains bass below 60 and the system is not time aligned the vagaries of instrument location can differ from note to note. For example D1= 37Hz; F1 = 43Hz; A1 = 55Hz, C=65Hz E2= 82 Hz. Depending on your crossover point, the localization of these notes will be distributed proportionally between the sub and the mains. If your sub is placed at a different location from the mains, the sound you hear will be localized accordingly depending on the note. The same instrument will appear to eminate from different locations depending on the note played. That is not what the microphone hears. The old adage that bass is not localized is totally fallacious. Anyone who attends classical concerts can easily point with one finger and their eyes closed to the source of an instrument with significant bass radiation such as a tympani, tuba, or single double bass from anywhere they sit.

The reason the famous Sheffield drum track is such a valuable evaluation tool is that the recording engineers (as stated in published interviews) were obsessed with reproducing both <30-40Hz bass fundamentals of the kick drum as well as the 90-120Hz components of the upper bass from the kick drum and the floor tom tom. A reproduction system that is truly time aligned will make Jim Keltner's trap set sound like mush a far as localization. Swarm subs make such reproduction sound completely unacceptable to me, event though the overall frequency response is "smooth". Again, what one prioritizes in your home reproduction system is simply personal preference. But accurate time alignment of the subs to mains is just something I cannot live without. It is the reason IMHO why most subs are not as sonically successful as they might be with more stringent set-up. Impulse measurements can be extremely valuable in facilitating such alignment. Unfortunately, such tools are not commonly used by audiophiles.

Marty
Are you talking about time alignment as a single impulse with a smooth decay... that requires subs to be quite a way forward of other drivers and if there is dsp , a loooong way forward.
Thats pretty tough to achieve without a complete digital domain crossover and multiple amps etc.

Then of course how is the music recorded and mixed ..

I agree with your proposition...we hear the bass notes when they first pass ( supposedly pitch is not clear) and it is possible they may assist in localization but its importance in the sea of tradeoffs in speaker design is not certain in my mind.
Having played with dsp crossovers to achieve linear phase and perfect time alignment it certainly creates an amazingly precise soundstage but that seems to me more a consequence of higher frequencies.
I must try some min phase crossovers and see if it shows at lf

Phil

 

[Holmz]

Agree to disagree Ralph. When I listen to reproduced orchestral music that contains bass below 60 and the system is not time aligned the vagaries of instrument location can differ from note to note. For example D1= 37Hz; F1 = 43Hz; A1 = 55Hz, C=65Hz E2= 82 Hz. Depending on your crossover point, the localization of these notes will be distributed proportionally between the sub and the mains. If your sub is placed at a different location from the mains, the sound you hear will be localized accordingly depending on the note. The same instrument will appear to eminate from different locations depending on the note played. That is not what the microphone hears. The old adage that bass is not localized is totally fallacious. Anyone who attends classical concerts can easily point with one finger and their eyes closed to the source of an instrument with significant bass radiation such as a tympani, tuba, or single double bass from anywhere they sit.

The reason the famous Sheffield drum track is such a valuable evaluation tool is that the recording engineers (as stated in published interviews) were obsessed with reproducing both <30-40Hz bass fundamentals of the kick drum as well as the 90-120Hz components of the upper bass from the kick drum and the floor tom tom. A reproduction system that is truly time aligned will make Jim Keltner's trap set sound like mush a far as localization. Swarm subs make such reproduction sound completely unacceptable to me, event though the overall frequency response is "smooth". Again, what one prioritizes in your home reproduction system is simply personal preference. But accurate time alignment of the subs to mains is just something I cannot live without. It is the reason IMHO why most subs are not as sonically successful as they might be with more stringent set-up. Impulse measurements can be extremely valuable in facilitating such alignment. Unfortunately, such tools are not commonly used by audiophiles.

The literature about localisation being difficult at low frequencies is pretty clear.
However teh distortion products at the 2nd, 3rd etc. can really start to get into the range where they are localised.
And any chuffing is clearly more broadband.

 

[Legolas]

I agree. Ron has 0 idea if the edginess was the preamp or the crossover. I would also lean to the crossover. My gut says the preamp did little to change the sound.

Ron really needs to disconnect the preamp and put the Hegel back in. I bet the edginess is still gone. Maybe he will deport the Italians. Unless he is dealing the line and recognizes the mark up on Aries is more $$ to pocket than Hegel.

No, the Aries Cerat Incito S is superb value, and the most affordable preamp AC make. It punches well above its price. It is also very neutral / uncoloured. I would look elsewhere in the system if there is a hardness issue.

 

[marty]

Marty
Are you talking about time alignment as a single impulse with a smooth decay... that requires subs to be quite a way forward of other drivers and if there is dsp , a loooong way forward.
Thats pretty tough to achieve without a complete digital domain crossover and multiple amps etc.

Then of course how is the music recorded and mixed ..

I agree with your proposition...we hear the bass notes when they first pass ( supposedly pitch is not clear) and it is possible they may assist in localization but its importance in the sea of tradeoffs in speaker design is not certain in my mind.
Having played with dsp crossovers to achieve linear phase and perfect time alignment it certainly creates an amazingly precise soundstage but that seems to me more a consequence of higher frequencies.
I must try some min phase crossovers and see if it shows at lf

Phil

Phil

Asking any single transducer to reproduce “what the microphone hears” is a tall order. When you divide the frequency range up into multiple drivers, with the lowest frequencies driven by a separate speaker (possible made by a different manufacturer) is even more difficult especially if they are in a different location from the mains. As has been discussed previously, if you are placing subs behind the mains, not using dsp to match the arrival time to the listener (by retarding the mains) leaves limited options. Without dsp, a good place to start is to aim for locating the sub so the voice coils of the drivers are in the same plane. Moving the sub front or back a bit can be helpful and for a variety of reasons, as you said, it might be that the best alignment of the subs might actually be to locate them a bit in front of the mains. (The problem with that is that it looks ridiculous and most audiophiles would never accept it.) But if you start off with the subs in, or reasonably close to the same plane as the low frequency diver of the mains, and with perhaps minimal use the phase control on the sub (if there is one), one might achieve an alignment that sounds good with minimal arrival time differences between the subs and mains. To reiterate, the best way to gain arrival time equivalence is to use dsp. Like many others, I’ve gone down that path for years as discussed elsewhere

https://www.whatsbestforum.com/threads/dsp-one-persons-experience.520/

but ultimately abandoned it because, similar to your observations, there were trade-offs in the mids and highs I was not willing to accept, so back to analog I went.

Marty