[carusoracer]

Looking for info on how and what people have used in their setups to power and crossover the 2nd voicecoil in the Gallo Reference 3 Speakers.
I spoke with Gallo and they recommended an Amplifier with a volume or gain control knob.
Also recommendations for XO and how to set them up.
My Gallo's should be here soon and I know I want the Bass to perform down to 25k

EE MiniMax PreAmp (NOS Tubes)
Musical Fidelity A3cr Power Amp
Music Hall Maveriick SACD player

[miklorsmith]

I used to own the Gallos.  I used an integrated amp with 6moons-recommended "Harrison Labs" low-pass filters, available on their ebay store.  They come in the form of twin-ended RCA jacks that go between the amp and interconnect.  The problem I had with them was that the lowest value they offer is 50 hz, where the primary voice coil is good to about 40 hz.  There was an unpleasant bump around the overlap.

Harrison offered two solutions:  Run two sets in series, effectively lowering total value or use one of their high-pass units for the main amp.  If you go with the first route, which was their second choice, talk to them about what the combinations ultimately yield.  I think my final solution was a 50 hz and a 100 hz, which gave an effective crossover around 40 hz.  

Their primary suggestion would put an additional filter in the signal path.  These units are reported to be fairly transparent, but I didn't want anything in the main amplifier range and avoided this route.

I had an integrated laying around that worked OK - about 70 wpc into 8 ohms.  The 4-ohm resistance would about double that for the second coil.  However, I never thought this was an optimal solution.  If I were to stick with the speakers, I'd get something similar to the dedicated Gallo amp.

Good luck!

[carusoracer]

Thanks for the reply it does sound like a tough situation.
How can you describe the "bump" did you ever eliminate it or gave up?
The reference Amp will not be out untill sometime in the summer?
 Also did you invert the connections on the speakers?

[Jack Gilvey]

My Gallo's should be here soon and I know I want the Bass to perform down to 25k

 Hmm...that might be tough...

[miklorsmith]

The bump was created by a single Harrison unit low-passed at 50 hz.  I eliminated the bump by going with two Harrison units in series.  This has its own troubles, as this arrangement reduces amp gain considerably.  I was unable to get enough juice out of the "sub" amp, though it definitely filled in the bottom end.

I did play with inverting phase.  When the mains only were connected, it definitely helped.  Trying both sets of posts in any combination was inconclusive.

Happy ears!

[djbnh]

The superimposed in-line low-pass filter is an FMod by Harrison Laboratory and spec'd as 50Hz @ 12dB/octave. Gracias to Kalman Rubinson of Stereophile for sharing the Crutchfield connection from whence I purchased this little $29 gizmo. I'd experiment with bi-amping the side-firing woofers' second voice coils...Dedicating two eVo 4 GenII channels to the Gallos' regular full-range inputs as you would any ordinary speaker, the two others were preceded by the 50Hz networks to power the woofers directly in parallel. While I was ready to take notes, I was not entirely prepared for what was to follow. In a nutshell, 'unassisted' and despite their brute appearance, these woofers began their roll-off around 40Hz. Some of this is clearly a slightly variable function of boundary reinforcement which was sorely lacking in my case. It will enter the picture in a regular, fully enclosed room of more common dimensions. However, with the twin-drive scheme in my unusually open environment, the drivers' roll-off was distinctly retarded. Response now extended fully audible to a shockingly taut 25Hz. How do I know? Look at the Avantgarde woofers above. Ask me how I wouldn't know!
...However, when I bi-amped the Gallos for 'active woofer drive', the only thing missing vis-a-vis the German monster subs was raw air displacement. That's no surprise. Any child would see that four sealed woofers driven from 250-watt dedicated high-current amps couldn't help but move more air. The Gallos also lacked the last word in infrasonic shudder on certain synth pedals of Trance/Ambient fare. However, the word 'lack' in this context is really a very feeble $2,500 joke. For all sane intents and purposes, the bi-amped Reference III is a bona fide full-range speaker that reaches to 25Hz in honest fashion. For obvious reasons, I cannot comment on the relative need for bi-amp augmentation in spaces smaller than my own. What I can stress unequivocally is to not use a higher low-pass filter value. You merely want to augment the woofers from the point at which they begin their natural roll-off. The next filter value in the FMod line is 70Hz. This will likely be a little higher than ideal and cause minor midbass fattening. That could be great shakes for movies -- and indeed was the case with the 80Hz THX-style sub-out from my modest T 751 NAD home-theater receiver -- but is far less desirable for linear 2-channel music with the greatest possible transparency.

I guess one AC listener (miklorsmith) and Srajan hear/address the same issue differently. carusoracer, perhaps reading Srajan's review is a good starting point, and best of luck in your own choice of what to do.

[tl1000sv]

I'm currently doing filtered biamping with my Gallos.  I use a dbx 223 crossover, which has attenuators (gain control) and infinite frequency cutoff adjustment

This strategy works fine and was inexpensive.  You can see the layout on my A'gon system here: http://forum.audiogon.com/cgi-bin/fr.pl?vopin&1108927202&read&3&zzlTl1000sv&&

You absolutely need a gain control of some sort.  But not for the reason you'd think.  The problem is that there is EMF that is generated in the primary voice coil, if the secondary voice coil overpowers the woofer.  This energy makes its way past the internal crossover and manifests itself as a nasty "pop" through the mids.

You need to find the CD with the most aggressive, loudest bass transient you have, and play it repeatedly, backing down the secondary bass gain until you can't hear any distortion.  It's a LOT lower than you think - hence the max output of only 200wpc @ 4 ohms of the Gallo SA amp.

My primary amp is a Belles 350A.  In the real world, about 50% of my jazz/rock/classical collection sounds better with bass augmentation, but the rest sounds better without.  I am coming to the conclusion that a REALLY strong primary amp is the ticket that makes these babies sing.  I've sent off the 350A for the Reference upgrade, which will then push out 64 amps of transient power.  If it makes a big difference, I will probably abandon bi-amping with these speakers.  So I'll update this thread when it gets back.

By the way, be aware of a big caveat of the passive line-level crossover (F-MOD) solutions.  If everything is just right, they work well.  However, the crossover frequency is derivative of the amplifier input impedance.  So what you think is a 70 Hz F-MOD could be a 45 Hz crossover in one system, and 130 Hz in another.  Harrison's website downplays this (there is a single hand-drawn graph that approximates the correlating curve), for obvious reasons.

Tim

[carusoracer]

Thanks for the reply.
I still do not see a picture of the DBX unit? Also where can one obtain them?

I will talk to Harrison on Monday for a good technical explanation before trying their setup.

I tried my Gallo's with a Buddy hooking up some bare crossovers and I simply have to have the 2nd voicecoil driven:-0
I like the sound of the speakers with out but Luv them with the additiional Bass output. It just seemed to complete the picture that the speakers con portray.
I'm also concerned about Matching impedence