[Housteau]

Things have been going very well.  I believe I have found a good position for the V60s that will allow the VLAs to be where I believe they will do their best.  It is the position you see in the photos.  That will all have to be worked out when that time comes though.  For now, I have been been working with my loaner sub to see how far that can take me, as it may be a good while before the VLAs are in country.

I ran across something this morning that really surprised me, so much so that I had to give Brian a quick call to see what he thought about it.  I did a frequency sweep of the system one Hz at a time with just the V60s running and with the sub plate amp off.  I was shocked to find that the V60s in my room went down to approx. 57 Hz before starting to roll off.  According to the hash marks on the subs plate amp, I have it set to roll in somewhat below that, possibly closer to 50 Hz.  A continuation of my frequency sweep with that amp on to the subwoofer did show a smooth transition to the lower frequencies.

When I had originally set the system up, I just did a few tones to balance all three amplifier levels to each other and placed the crossover frequency where it sounded the best.  I had not taken to the time to see what each hash mark represented and assumed it was actually closer to that 70 Hz hinge point I have read so much about.

Add into the mix a parametric notch filter and 0 - 180 phase control and this is one versatile system that should work really well in any number of listening spaces.

I just thought that this learning was worth passing on.

[James Romeyn]

I would have thought that a speaker as coherent from top to bottom and revealing as this one is would be more ruthlessly critical of less than optimum recordings.  But, I haven't yet found this to be true.  Maybe it is the purity of the reproduction that allows them to be heard properly for the first time?

That is what I think is true too. Every time I really advanced my system, or heard something really good elsewhere, I found more and more recordings enjoyable. For some of them I thought are unlistenable before. Now I'm much more careful before I name a recording as bad.

I couldn't agree more.  I just plugged in my new Bongiorno Ambrosia preamp, one of 5 sum total in the USA.  I previously thought a Ricki Lee Jones & Wayne Newton CD had only one or two good songs.  While listening, the sound was so good I just sat back & listened to most of the CDs & enjoyed them very much. 

Dave,
I thought your IRS 1bs looked great in your room, very stately, beautiful.  But the V60s look just off the scale good, another level altogether.

You should can the look of that room & sell it!  You could pay for 10 more V60 systems!   

[Housteau]

I thought your IRS 1bs looked great in your room, very stately, beautiful.  But the V60s look just off the scale good, another level altogether.

Thank you Jim.  I live in a small town and only wish there were more audiophiles about so we could share experiences and learning's.  I only know of one right now and really envy the local clubs that larger cities have.  I guess not having access to that sort of thing makes forums such as this a very valuable resource to me. 

When I look at the V60s, the word majestic very much comes to mind.  I find them stunning and much more attractive than any of the older and newer designs out there.  Also, after living with them this passed week and a half, I have no doubt that once mated with the VLAs they would stand up easily to the old Infinity IRS V and Genesis I statement systems in regards to the presentation of shear sonic pleasure.  I think they come darn close now with just this single subwoofer.

My listening room is special, but I don't want everyone to think that my entire home is like that though.  My home is actually a very modest 1500 square foot slab house built around 1976.  I had the listening room built as a separate structure behind my house as part of a detached garage.  Being separate has some distinct advantages.  It allows me to listen late at night without disturbing anyone in the house.  My wife generally turns in very early as she get up early for work in the morning.

[John Casler]

And for those of you who don't know, Dave is on more than the "cutting edge" of Audio, he is also a "Swordsman".

If you look closely at his avatar, those are swords, and many of them, in that picture.

[PLMONROE]

<Dave,
I thought your IRS 1bs looked great in your room, very stately, beautiful.  But the V60s look just off the scale good, another level altogether.

You should can the look of that room & sell it!  You could pay for 10 more V60 systems!>   


That's for sure! From what I can tell of Dave's pictures if the old "Audio Video Interiors" magazine was still in monthly publication his sound room could make     "center fold"

Paul

[Housteau]

I have noticed a small issue with using these bridging circuits that I wanted to pass on.  Depending upon your amplifiers you may experience more transformer hum coming from the speakers.

My mono VTLs have their own mild signature hum that I have grown used to and don't find unusual at all.  I find it very similar to any number of systems I have heard over the years.  My Eagle 2a also has its own hum that was noticeable on my former Infinity bass towers.  They carried the frequencies from 150 Hz on down and were positioned flanking my main speakers with just a slight toe-in.  That hum was only noticeable if I moved out of the sweet spot off to the side and more in front of where they were pointing.

The V60s on the other hand carry the frequencies down to the high 50s before rolling off, and are positioned more towards the listener.  Because of these two facts, I now hear the hum from both amplifiers where before it was just from the VTLs.  Adding to that is the nature of the bridging circuit.

This circuit works by taking the output of one amplifier and feeding to the input of another.  Since I am biamping the v60s, my Eagle 2a's input is the output from my VTLs.  What is happening is the Eagle is receiving the hum from the VTL and adding that to its own hum signature.

Now it isn't that bad, but it is very noticeable to me in the absolute dead silence between CD tracks, but not much at all with LPs.  Generally, once the lowest level of music begins, such as a single piano note, that hum fades into the background blackness.  It doesn't appear to effect the music at all and just exists as an artifact when no music is playing.

[John Casler]

<Dave,
I thought your IRS 1bs looked great in your room, very stately, beautiful.  But the V60s look just off the scale good, another level altogether.

You should can the look of that room & sell it!  You could pay for 10 more V60 systems!>   


That's for sure! From what I can tell of Dave's pictures if the old "Audio Video Interiors" magazine was still in monthly publication his sound room could make     "center fold"

Paul

Yes, Dave's room and pics are so good that it is now featured on the VMPS Website.



Look here: http://www.vmpsaudio.com/RMV60.htm  and scroll down

[James Romeyn]

Good job, folks!  I sent two of Dave's pics to a friend.  It looks great seeing them in such a fantastic room, much better than a blank backdrop...Our own VMPS "Reality Show"!!!!!!!!!

[James Romeyn]

I have noticed a small issue with using these bridging circuits that I wanted to pass on.  Depending upon your amplifiers you may experience more transformer hum coming from the speakers.

My mono VTLs have their own mild signature hum that I have grown used to and don't find unusual at all.  I find it very similar to any number of systems I have heard over the years.  My Eagle 2a also has its own hum that was noticeable on my former Infinity bass towers.  They carried the frequencies from 150 Hz on down and were positioned flanking my main speakers with just a slight toe-in.  That hum was only noticeable if I moved out of the sweet spot off to the side and more in front of where they were pointing.

The V60s on the other hand carry the frequencies down to the high 50s before rolling off, and are positioned more towards the listener.  Because of these two facts, I now hear the hum from both amplifiers where before it was just from the VTLs.  Adding to that is the nature of the bridging circuit.

This circuit works by taking the output of one amplifier and feeding to the input of another.  Since I am biamping the v60s, my Eagle 2a's input is the output from my VTLs.  What is happening is the Eagle is receiving the hum from the VTL and adding that to its own hum signature.

Now it isn't that bad, but it is very noticeable to me in the absolute dead silence between CD tracks, but not much at all with LPs.  Generally, once the lowest level of music begins, such as a single piano note, that hum fades into the background blackness.  It doesn't appear to effect the music at all and just exists as an artifact when no music is playing.

Dave
Here's another circuit I've used to good effect.  It should minimize the hum if that's of interest.

It's an inexpensive low-level high-pass xo; it's passive but is employed as if it was active.  When its 1st order electrical slope is combined w/ the midbass 2nd order mechanical cutoff (sealed enclosure) you should have approximately a 3rd order total effective slope.  If desired the pole is easily tuned above the 50-some Hz you have measured for the midbass cutoff; this would allow a higher notch pole w/ the sub xo.   

A single cap or bank of paralleled caps are inserted in series at the input to your midbass Eagle amp.  Use small-value polarized speaker xo caps.  Start w/ about .022, .033 or .047mF; the pole is altered by adding/subtracting .01 &/or .001mF caps in parallel w/ the original cap.  Doubling the cap value cuts the pole frequency in half; conversely halving the value doubles the pole.  Brian may send you a selection of mylar caps for a nominal fee.       

When I tried it I employed mylar caps & RCA plugs & chassis-mount jacks just before the midbass amp input; test leads w/ alligator clips were used to add/subtract caps.  It worked well.  After you select your favorite values you could make a permanent jumper gizmo w/ the RCA plug/jack (my preference) or solder the caps inside the amp at the inputs. 

Favorite RCA is the copper-gold Vampire.  I'll look up the number if interested. 
If the amp employing this was used up into higher midrange frequencies or above the caps might add audible distortion, but likely fine up to the middle C xo-pole of the midbass.   
 

[Housteau]

I can see how changing the pole frequency could shift some of that extra low bass hum more outboard and offline to the subwoofer system.  That is interesting. 

When the VLA sub bass systems arrive they will be positioned more into the room and away from that back wall a bit.  They will also be a line source of low bass.  I am familiar with how the Infinity bass towers reacted when their positions changed in a similar manner.  So, I am thinking that the roll-off the V60 bass pedestals have now will work very well with this complete system, and I may not want to change it.  But, it is good to have that option to play with.

As you know, my original need for the bridging circuit was due to the low impedance load the mono subwoofer plate amps would present to my tubed preamp, driving them in parallel with what I was driving the V60 with.  The magic of that circuit not only allows me to do that safely without signal loss, but to also biamp the V60 itself through a gain adjustable bridging cable to the mid bass amp.  One of the additional benefits of this second cable is the ability to now run with the V60 L-pads wide open effectively removing  them from the circuit.  Now there is the equivalent of straight wire between the drivers and the EL34 tubes of the VTLs.  I like that.
             
The option I have yet to try, is to just run my VTLs and Eagle in parallel off my Audio Research preamp.  There are no impedance issues there, but I would need to balance the two amp systems to each other by either using the L-pads on the speaker, or in some other way.  That would eliminate the extra hum, but may take away from something else.  I will have to experiment when I get back home and see how this may work.

Paul (PLMONROE) is doing this now and has not had any issues.  The input sensitivities of his two amps are close enough that the L-pads did not have to move much from the factory setting, if at all.  However, I don't think the the sensitivities on mine are as close as his are.

[James Romeyn]

Dave
I wish you made MY bridging circuit!  Yowza!  Yours looks so SEXY!  When did you work for NASA?  Scratch that...when did you train for electrical work on nuclear-powered subs?

[PLMONROE]

What size will be the footprint of the VLAs? (am rearranging my soundroom)

[Housteau]

I think they are about 14" x 19".  Did you see the pictoral representation of the new design that dubravko
posted?

http://www.audiocircle.com/index.php?topic=16687.70

[Brian Cheney]

The columns are 14 1/2" W x 20"D x 68"H and the base is 1" wider all around, so footprint is 16 1/2"W x 22"D.

[PLMONROE]

Did you see the pictorial representation of the new design that dubravko
posted?

http://www.audiocircle.com/index.php?topic=16687.70

Yeah! I got a new name for John -- those are so beautiful they should be called the Brian Cheney "Michelangelo Edition"

[James Romeyn]

Did you see the pictorial representation of the new design that dubravko
posted?

http://www.audiocircle.com/index.php?topic=16687.70

Yeah! I got a new name for John -- those are so beautiful they should be called the Brian Cheney "Michelangelo Edition"

Note to Brian: Yes.  Go for it.  Rub it in.  It's justified.  The VMPS "Michelangelo Series"     

[Housteau]

Since I have been home, I removed one of the 'bridging circuit' interconnect pairs that I was using to biamp the V60s with.  In their place I ran both my VTL monos and Iverson Eagle 2a directly in parallel off of my Audio Research preamp.  I knew that there were no impedance issues there, but I was not sure if there was adequate adjustment available within the L-pads to allow for the input sensitivity differences between the high and low frequency amplifiers.  Well, in my case there is and by a good margin.

My other concern was with the potential of loosing some clarity by no longer using the L-pads in a wide open configuration.  I am sure that there is a benefit to running them fully bypassed, but in all honesty, I have not yet noticed any detrimental effects at all by having them rolled back.

The removal of that one circuit also removed that added amplifier hum I mentioned a few posts back.

[James Romeyn]

Well, I hate it when Brian's theories are supported by personal experience!  Drat!  Foiled again!  It was interesting recently hearing another speaker designer state that the only l-pads worth using cost $150ea (Brian's cost much less obviously).

Good work!  I'm glad you reported that, because I'm about to transform my system & must use the L-pads.  It's good to know it still sounds good!

[PLMONROE]

My experience parallels Dave's. Try as I might I can hear no sonic difference  with L-pads in or out.

Paul