[Roc]

John & George.

Thanks for posting the pictures.

You should post the one showing the beautiful MLS cabinet too.

Wood is African Ebony.

Dave

[ctviggen]

That's a "wife friendly" system!     Are you also biamping the RM40s?

[zybar]

John & George.

Thanks for posting the pictures.

You should post the one showing the beautiful MLS cabinet too.

Wood is African Ebony.

Dave

Dave,

It was all John.

Hopefully we can get some more pics of the speakers and room.

George

[Roc]

That's a "wife friendly" system!     Are you also bi-amping the RM40s?

Got rid of the wife, kept the stereo !
No more moaning about how the room looks or how much money I'm wasting.

I'm double bi-wiring.  Not bi-amping.
The wires you see are 20' long, and rolled up currently.
Ordered new (shorter) spkr wires from big John.
Should have them next wk.

I have lots of pic's of the spkr's.
I'll send some more to John and he can post what he likes.

Hard to tell in these pic's but I'm using a "back against the wall" listening arrangement.
Read about this in "mapleshades" magazine.  Didn't pay much attention to it.
Then saw/heard big Johns "Listening chamber" and decided to give it a try.

My Listening position is against the treated (dead-end) wall.
Speakers are literally in the middle of the room, firing into the dead end.

Benefits:
More powerful and extended bass. 
Huge soundstage, most realistic I've heard. 
Enhanced perception of depth between musicians. 
Feels exactly like being at concert. 

Down side:
All the sonic defects of the room are more pronounced and come right at ya.
Had to acoustically treat the entire room, add more bass traps, etc. and I'm still not quite there yet.
Speaker placement and PR damping are more critical than ever.
And that top woofer on the RM-40's is giving me more grief.

I'll be out of the office for a week and won't be able to keep up with this thread.   

Dave

[James Romeyn]

Can current owners get a sticky w/ detailed instructions & pictures on how to remove the crossover and reinstall the OXO?

Obviously w/ the pots and crossover external something has to change internally w/ the speaker.

Thanks.

I doubt B will get time for that.  I'll put it on my to do list but doubt I'll have time till early '07 after I move.

[James Romeyn]

And that top woofer on the RM-40's is giving me more grief.

Dave

Dave
Brian won't take my advice, but IMO the 40 sounds better w/ the midbass at the floor & the lowbass at the ceiling (later 40s may have dual low bass & no midbass driver, unsure).  He doesn't notice it so much in his soundroom because his seat is very far from the speakers.

[James Romeyn]

My RM30C MLS TRT BH5, Supermax OXO, variations: Stan Warren wire & xo-to-spkr wire nut junctions (plastic non-conductive mechanical binding posts will replace the wire nuts later)

[lonewolfny42]

Now you see it better....

[Eugene2]

Received my supermax 30m  :thumb:today.  Have them burning in, my 91 yr old Dad was helping me connect my very difficult to maneuver Virtual Dynamics Master bi-wire cable.  After we completed the setup, we put on a mapleshade blues cd and he said "dern! sounds like he is standing in the room!,"  I felt the same way.  Cannot wait until they finish breaking in.

[lifewithmusic]

So . .  . the OXO is a passive crossover. 

Brian, do you make an active crossover? Aren't active crossover's typically supposed to have advantages over passive crossovers?

[James Romeyn]

B doesn't make an active xo now.  This has been rehashed a lot lately, but here goes again.

Passive

Pro: Only alternative for single amp.  Less cost/complexity/clutter/floorspace.  May accomodate a seperate amp for each range of the speaker system w/ seperate inputs.

3 different cap grades available: standard, $550/pr, $1200/pr msrp.  Upgradable.

Provides the August '06-released passive eq curves.  Combined w/ tweeter de-horning, the passive eq provides the inverse of the curve anomaly caused by the CDW.  A non-eq'd CDW tends to sound sound dull & lifeless.  The properly eq'd CDW works splendidly.

Distortion introduced by passive xo components passes directly to the speaker drivers & is not multiplied by a downstream amplifer, such as the case w/ an active xo. 


Con: Interaction between amp & speakers causing potential performance degradation depending on the amp's architecure & the load/complexity of the xo & speakers.  The vmps loads seem moderate.  If the most expensive TRT caps are employed, the weakest link is the passive low-pass coil on the bass, which decreases the damping factor & may slow transient performance.  How much can only be quantified by direct A-B w/ a particular active xo.     
When single-amping, L-pad attenuation required, degrading ribbon transparency.  Again, can only be quantified by direct A-B w/ a particular active xo.  Can be minimized by regular treatment of contacts w/ Caig ProGold.

Active

Pro: Amps & speaker drivers are direct-coupled.  Best damping factor, esp relative to bass drivers.

Con: Any & all distortion caused by the active circuitry, including the level control system, is multiplied many times over by the amplifier downstream. 

Cost/clutter/floorspace/heat.  Requires one amp + its power cord, pair of interconnects & speaker cables for each range being actively x'd. 

A CDW-equipped VMPS ribbon will sound dull & lifeless if the active xo does not include the proper eq curves.  Such eq curves may be impossible to replicate in production analog active xo's; in other words, I hope you like to solder because you may need to build it.  The alternative (a bad one because of it's negative impact on ribbon transparency) would be to provide the eq via four eq ch's (one per each mid/treble range) in series w/ the xo-YECH!!!!!!  The AudioCircle active digital xo guru is ekovalsky, one of the nicest & most generous people w/ his time at the circle.  You'll have to ask him if the current active digital eq's can accomodate a 1st order high-pass eq filter slope at 5 kHz.  Please notify us all after you find out because curious minds want to know.           


Notes

Any statements comparing the general attributes of active to passive should be considered misleading & worthless in deciding the actual subjective value of one specific passive xo vs. one  specific active xo. 

That said, based on my experience w/ the CDW, I feel 100% certain in predicting, on a current VMPS-CDW-equipped speaker, that an outboard TRT xo w/ current passive eq curves would blow away ANY active xo not duplicating the proper eq curves, especially if the passive xo's were driven by the same three amplifiers that are absolutely necessary in the active xo rig.

Right now, based on what I know, the one & only range that would positively only benefit by a good 1st or 4th order active low-pass xo is the bass, as long as the pole could be adjusted +/-10 Hz in single-Hz steps centered around the OEM pole frequency (sorry I forgot, between 260-280 Hz).  If a sub is employed, it would be exceptionally nice if the midbass drivers also had a 1st or 4th order active high-pass filter pole.  This would allow the user to tune around (create a hole) at the normal ceiling-floor mode around 70 Hz.   

IMO any active xo not able to replicate the necessary eq slope for the CDW (1st order high-pass pole @ 20 kHz, flat at 5 kHz) can & probably should be ignored.  Want to know the effect?  Find a VMPS ribbon speaker designed & built w/ original tweeter horns, standard grills & NO passive eq modifications for the CDW (= pre-August '06).  Find a CDW for that speaker model.  Replace the standard grill w/ the CDW.  What happened to the tonal balance?  Inquiring minds need to know.     

We all wait breathlessly for Brian's 3 to 6 word answer to the same post   
  

[lifewithmusic]

Thanks Jim.  That's what I wanted to know, and kinda what I thought.  You said better than I've seen any of that articulated any where else on this board.

[PLMONROE]

This may be a dumb question but it is a point on which I guess I am unclear. As I understand it, in passive bi-amping the incoming signal is split, typically through a Y connector and fed to two amplifiers. One powers the bass spectrum while the other powers treble with the internal crossover separating the two. What is gained (if anything) by using an electronic crossover to split the incoming signal ahead of the amplifiers? It would seem that this adds equipment into the chain to split the signal that the internal crossover would later split anyway. Is an electronic crossover only appropriate for active bi-amping or am I getting tied up with semantics (or something)?

[James Romeyn]

Normally, each range of the speaker will be either passively or actively x'd.  You will probably never find the same pole in a speaker x'd both actively & passively.  This would entail the active xo in series w/ the passive xo for the same pole, & that would make simply no sense at all (not saying impossible, but makes no engineering sense).  Conversely, you COULD potentially have one pole (e.g. low-pass) of one speaker range x'd actively, while the other pole (high-pass) of the same speaker range was x'd passively. 

Earlier vmps models such as the SuperTower III & FF-series SRE Active & other makes & models such as Infinity & Genesis, have some range actively x'd (normally the bass), while upper ranges are passively x'd.

Every time a HT processor has it's high-pass filter employed for smaller speakers, active & passive xo's are being mixed in series.  The HT filter is  active upstream, while most regular speakers' internal xo is of course passive, located dowstream in the chain.

Most or all full-range speakers that include a sub amp mix active & passive xo's.  It can get as complicated as your imagination. 

Hope this helps rather than hinders your understanding. 

[PLMONROE]

HUH?  (Sorry)

[John Casler]

This may be a dumb question but it is a point on which I guess I am unclear. As I understand it, in passive bi-amping the incoming signal is split, typically through a Y connector and fed to two amplifiers. One powers the bass spectrum while the other powers treble with the internal crossover separating the two. What is gained (if anything) by using an electronic crossover to split the incoming signal ahead of the amplifiers? It would seem that this adds equipment into the chain to split the signal that the internal crossover would later split anyway. Is an electronic crossover only appropriate for active bi-amping or am I getting tied up with semantics (or something)?

Hi Paul,

Brian either has, or will be, looking into the "potential" of active digital x-overs.

He has your DEQX unit, and I think Andre from E-speaker was supposed to have (or will be) stopping in to bring him up to speed on the use of it.

I have not used the DEQX and am not sure of its full potential, but I assume if B, gets it operating he will be able to quickly evaluate it, and if it would allow him the tools and parameters he might need to maximize the potential of the technology.

In the case of the new VMPS speakers, they all can be ordered in Direct Drive versions, without internal X-overs, which would answer your question about the signal being "processed" twice.  It would not.

Now if one has an older VMPS model that has the internal crossover, and uses an external active x-over, then yes the signal would then be processed twice, and I might think to the detriment of the sound.

[PLMONROE]

That's really great, John! Thanks loads. aa

[James Romeyn]

John
This is why you make the big bucks: Why don't you find out for us whether or not any of the most popular digital xo's can simultaneously provide the xo function & a 1st-order upward tilt @ 5 kHz eq, that is apparently absolutely positively mandatory for the CDW to properly function.  It certainly appears the whole subject of full active eq for any CDW ribbon is a moot point till the eq & xo are both accomplished.  Dr. Kevolsky certainly knows the answer to this conundrum.   

I suppose, if necessary, the eq & xo functions could possibly be performed in the digital domain in two different & seperate components daisy-chained in series (one eq, one xo), though that appears to be not ideal for several obvious reasons: clutter, cost, expense, cost, potential negative effect on transparency. 

[warnerwh]

The Behringer DCX 2496 I believe what you ask Jim. It is a digital crossover with parametric equalization built it. I've not got one but had been reading the manual a bit recently so am not sure of it's full potential.

[John Casler]

John
This is why you make the big bucks: Why don't you find out for us whether or not any of the most popular digital xo's can simultaneously provide the xo function & a 1st-order upward tilt @ 5 kHz eq, that is apparently absolutely positively mandatory for the CDW to properly function.  It certainly appears the whole subject of full active eq for any CDW ribbon is a moot point till the eq & xo are both accomplished.  Dr. Kevolsky certainly knows the answer to this conundrum.   

I suppose, if necessary, the eq & xo functions could possibly be performed in the digital domain in two different & seperate components daisy-chained in series (one eq, one xo), though that appears to be not ideal for several obvious reasons: clutter, cost, expense, cost, potential negative effect on transparency. 

It is my understanding that the DEQX has those exact functions and more, but only after the Maestro has given it the "OK"  will we know if it does the real deed, as per "how we like it".

If you want to look at the technical capabilities, just go to the DEQX site and check it out.

http://www.deqx.com/

But it is all "whistling dixie" until B, thinks it will fill the need.

I have my doubts that it will exceed passive XO's in all areas, but it may offer Brian a more flexible canvas on which to paint his Sonic Landscapes.

Only time will tell.  They'll also be at CES

and what are these Big Bucks, you're talking about??