[vmpsownerrrrp]

Greetings:

New here, and need help in an attempt to experiment with vertical biamping. I own a pair of VMPS Super Tower R Special Edition (side attached ribbon midrange panels) circa 2002. I have the John Curl designed VMPS Electonic Crossover, and understand how to biamp horizontally using the electronic crossover. Brian and my dealer explained the horizontal setup long ago.

Now that I have new mono block power amps, which can also be run in stereo, with volume controls, I would like to try vertical biamping, without an electronic crossover. Please know that though I can speak some of the stereo jargon / lingo, I have no intuitive, scientific, or intellectual understanding of stereo equipment, or connections, so please be patient with my lack of understanding the processes involved.

My first question is simply... are my speakers capable of vertical biamping / biwiring without a lot of internal rewiring of the speakers /
or internal adjustment of the crossovers? (I know they are capable of horizontal biamping using the 2 pairs of binding posts and the toggle switch in up position).

My goal would be as follows, from reading up on how to vertically biamp:

1. For my left channel speaker, use one amp in stereo mode with the preamp sending left channel information to the amp, which will be wired to run the bass with one channel and the tweeters / midrange / ribbon midrange with the other amp channel.
2. And then also do the same for the right channel speaker.
I do have 4 speaker wires (2 pairs) ready to go.

To clarify, my speakers have the 2 pairs of binding posts, upper and lower, and the toggle switch with down position for single amp use and up position for biamping.

Thanks to anyone who can help...
Stephen

[RSorak]

Changing from hor to vert biamping in no way does away for the need for the crossover, and in fact to me demands a 2nd one to be done right..{I guess you could put the crossover before the amp, and send its Low FR output into both the L and the High FR into both R and it would still do job w just 1}...Sending full freq signal to the tweeters is NOT recommended and is why you still need a crossover.

[James Romeyn]

...I own a pair of VMPS Super Tower R Special Edition (side attached ribbon midrange panels) circa 2002. I have the John Curl designed VMPS Electonic Crossover, and understand how to biamp horizontally using the electronic crossover.  Brian and my dealer explained the horizontal setup long ago...

...I would like to try vertical biamping, without an electronic crossover...

...tweeters / midrange / ribbon midrange with the other amp channel...
 

IMO it's critical to provide an image of the speaker for proper reply.  Are you the original owner?  Asking just to confirm the speaker was originally the model you list above.  "Midrange/ribbon midrange" doesn't make sense; the image will clear this up.   


IIRC VMPS Super Tower/R w/side mounted mid(s) came in 3 versions in this ascending sequence:

• BG single large true ribbon, called "ST/R Special Ribbon Edition," requires and includes transformer for the ribbon, IIRC no separate tweeter because the ribbon provides full extension, high ribbon failure rate
• Multiple 8" BG ribbons, no transformer, Infinity-type spiral planar tweeters on baffle
• Multiple 8" planar drivers, ditto Infinity-type spiral planar tweeters on baffle

Only #1 above requires the active JC low-pass active xo, because the ribbon is crossed around 133 Hz.  Passive low pass crossover on the woofers @ this low a frequency has too much loss.   


I can't recall the highest pole in Curl's xo, but IIRC it's too low to use with #2 and #3; IIRC #2 mids cross around 750 Hz, #3 mids cross @ 260 Hz.


Regardless: if your speaker is properly wired to use with Curl's xo, the speaker has no passive low pass woofer xo, and requires an active LP xo, full stop, no exception; there's no option to omit the active LP xo.   


Further, AFAIK, all #2 and #3 have passive low pass woofer xo only, no active LP is possible because the xo pole is higher than the range of Curl's xo. 


As already correctly posted, there's sum total no internal speaker difference correlating to the use of vertical vs. horizontal biamp.


Lastly, #3 has a huge peak @ 1k Hz, circa 6 dB IIRC.  I heard countless VMPS with this midrange as is, and near the end, with that peak fixed with DSP.  To say the latter outperformed the former is a gross understatement.   


If you have #3 and have no DSP to fix that peak, I suggest it's mandatory to use an amp (several affordable available now) with DSP to fix that bump.  A speaker xo designer might be able to design a passive notch for that peak, but I have no idea how successful would be such fix.