Is Bi - amping worth the trouble?

Now, you're beginning to get it.

So back to your origional question: Is it worth it?

I had a pair of power pigs and an old 100 wpc amp. It was a very strong 100 watts though but I auditioned another pair of monoblocks that were much more refined and had great imaging. Unfortunately the monoblocks didn't have nearly the bass depth and slam. No problem, just use all the amps, right?

The good part was that the bass crossover was at 90 Hz. If it was any higher, it would be more difficult because the hearing is more sensitive in the midbass.

Still, not that simple. First, the old amp was inverting. Easy fix; reverse speaker wires to bass. Then the gains didn't match so I went down to the doohicky shop and bought a 5 KOhm carbon potentiometer, a box and some female RCA's. Wired that up and twiddled for weeks. It was better but not quite right. Every time I changed the volume, I had to adjust the gain. Every CD had to dialed in. Even then, it always seemed bloated around the crossover point. Went back for a different doohicky. This time, it was a wire-wound pot. No better. Another thing that happens with multiple amps is ground loops and hum. Just another part of the learning experience.

Started looking at active crossovers and what would be involved. They ain't cheap. While I knew the crossover point, I could not find the slope of the passives in the speaker. Considering that each order (1st, 2nd...) adds 90 degrees of phase and and the speakers were designed to be coherent at one of those, I thought I should know. Turns out that wasn't relevant because active X-overs have a choice between 24dB/octave and 48(8th order). I also started to learn something about notch filters that I could not account for. In the speaker, the x-over was soldered on a circuit board. This seemed like brain surgery at the time and I could have ended up with a pile of parts. Now, with a bit more knowledge, these aren't simple problems but nothing insurmountable.

There was one other alternative, or so I thought. I bought a dual, 23 position rotary switch (attenuator) and a bag of resistors. This ain't cheap either and it certainly wasn't easy but Mr. Doohicky was happy.. Soldering 46 tiny resitors on a tiny switch is not fun. The ones that can be bought preassembled had a higher range than I needed. I chose all the resistors between 1K and 3K and added a DPDT switch that added another 3K (paralleled 6K), 6K or nada. Much better. No more fiddling with it, at least not after the first month, and no bloating. It also gave a great way to adjust the bass to my tastes. The DPDT switch turned out to be unnecessary.

Granted, an active would have killed that passive parasite and made the speaker much more efficient, I still have to wonder. I was planning on building a set of speakers from the ground up with an active x-over, because I'm convinced that's the best, but a sweet deal popped up.

The next set of speakers had an active x-over/bass amp from the factory. Well, semi-active, but let's not go there. It has controls for gain, low-pass, hi-pass and phase. Hooked it up with those little monoblocks because I didn't exxpect the midbass and up to take much power. Lots of trial and error with the settings and location. Changed from RCA to XLR. Different preamps, even built one myself. Learned that phase is more than quarter turns (90 degrees) and could hear within 10 to 15 degrees on either side and went for the middle.

No matter what I did, there was a dip at the crossover until a friend brought over his behemoth SS amp and the dip went away. I also tried with tube amps but not my taste. You could say the little monoblocks was a mismatch of character. The 1600 watt bass amp had a lot more. I was expecting to buy a new amp for the speakers but not quite so soon. Now, I've got three behemoths and it all worked out beautifully. By the way, bridging does work for some amps.

If you want to know see how complex it can be to make a versatile x-over, check out Wisdom's "Brain".

Did you expect a short story?

I am sorry Blindjim to scare you like this, but this is what it means when somebody talks about using an active Xover to change slopes or Xover points, and bipassing the speakers XOver.

Like I said on my first post:
Just use the Xover in your speakers, they were designed with them and you should keep them, just add a tubed amp in the mids and highs, and an SS on the bottom, use a passive preamp like the EVS attenuators or the Luminous Audio preamp on the bass amp and let the tubed amp run free. The speaker xover will allow your speakers to do their job properly.

I recommended a passive attenuator to match the gain on both amps, it is always best to "loose" some definition on the bass than on the mids, that is why the volume should be adjusted on the SS amp. To add an active stage (active XO) just for this would take away from the signal, because of this Marchand Electronics made a Bass Correction EQ :
http://www.marchandelec.com/wm8.html
Which is like an Active Xover for bass only, adding some other niceties... and leaving the mid and high source as pure as possible.

"I can add another pair of ICs... another amp... maybe make a move in changing out my speaker cables"

That is all it takes!

"I'd even go so far as to add another device like an outboard X over"

This would be good also, I would use the bass correction thingy for "bass" and a passive line level XO for the only other amp: the tube amp.

If you love this too much, in a couple of years you will be gutting your speakers to tear away the original Xover and hard wire....and maybe not, I wouldnt do it....I would get horns for that!!!

All the Best!

Ngjockey

“Did you expect a short story?”

uh, well, yeah, I did. At the onset. Not now, however.
Man! That’s a lot of doing… we can nix the soldering business right off.. I’m a plug and play sort these days… though not by choice. Thanks much.

Jsadurni
“I am sorry Blindjim to scare you like this, but this is what it means when somebody talks about using an active Xover to change slopes or Xover points, and bipassing the speakers XOver.”

…it will take a mite more than this info to scare me off… far more, for I’ve faced far worse.

“use a passive preamp like the EVS attenuators or the Luminous Audio preamp on the bass amp and let the tubed amp run free. The speaker xover will allow your speakers to do their job properly.”

…. So simply attenuate the bottom amp with one of these items? So come out of the preamp to “IT” AND then to the amp? OK… a gizmo and two more sets of ics…. Yikes! Though that’s the cheapest path thus far … I think.

“If you love this too much, in a couple of years you will be gutting your speakers to tear away the original Xover and hard wire....and maybe not, I wouldnt do it....I would get horns for that!!!”

…not bloody likely. Were I to survive this endeavor, you can stick a fork in me. . .. I’m done. Well save the tube rolling, isoing, and PCing…. And extra riders on the home owners.

I just got off the phone w/BAT. Had a short little chat with VK. He uses a lot of words like perhaps, maybe, it’s possible, and so forth…. Yet he is inclined to think my now ‘semi’ debunked (there’s been a spurious post mortem resurrection, albeit short lived or no), plan should either be a safe & secure one that remains bright and shiny still, or ‘perhaps’ not. Still in all, he did say just what you did apart from the passive X over makers name…. he seemed to think or indicated that an ‘inline’ (one for each outgoing IC to the SS amp), was available. Plug & play! But no idea of who made them… but thereby just pluggin into the preamp, and moving the dial… IF things weren’t homogenous. He also cast his vote for the VK 75/75SE, along the way. Naturally. I am inclined to go with BAT up top… or a VAC, or…, we’ll see., but at least 60wpc or above.

He also indicated some degree of flexibility with the use of the various speaker taps on the amp as some accommodation… but did say it would affect more than the ‘matching’ aspect, and affect the sonics to some degree.

Any hesitation I uttered was only due to expense. Not involvement. Given things always work out just the way they are supposed to…. One way or the other… I still remain 100% undaunted (almost). You might even say “I am entrenched with my upcoming effort to bi-amp”. I wouldn’t but you might.

Is there such a thing as an inline attenuator like what VK said? If so, are they worth having?

I remain deeply grateful for any and all input/experiences provided me and others herein…. Really.
Many thanks.

What Jsadurni says seems to make sense to me with the 4JRS since the mid-high box and the bass box are independent. If you can adjust for gain differences you should be able to bring the drive of SS to the bass and the strengths of tubes to the mid-high. I guess I was thinking that the DB99 essentially did this with an independently amplified woofer (I am guessing it is crossed over on its own).

This is what the 4JR manual says:

BI-AMPING THE VR-4 SERIES: If the tightest bass is desired, use a solid state amplifier on the woofer modules. If you value “image float” and liquid-sounding midrange/treble response, use a tube amplifier on the M/T’s. You will not need an outboard crossover, since the crossovers in the speakers will still continue to work. Although it is true that louder output can be obtained by high-pass filtering the tube amp, the loss of transparency is usually not worth it, and the clean volume obtainable without a high-pass crossover will be usually satisfying for anyone but a metal head.

Blindjim, you want a plug and play? Cheapest possible? Here you go, simply run your BAT on the Mid / High section.. Remove the jumpers of course on the speakers, and By a CROWN K series digital Pro power amp, it has about 1k watts per channel so you will have no problem with bass slam and transparency, and they can be found cheap on ebay and things(around 600 plus used).. Also it is digital so it runs dead quiet, No heat, tons of power for Live concerts because that is what they are used for, many people use these for subwoofer setups in real hiend theaters and 2 channel.

Now it also has Level knobs built right into it so you can adjust the gain on the amp to match up to the bass output you want without effecting the output of the Bat or anything at all for that matter.. However you will need to run a balanced cable cause they only have XLR and maybe 1/4" connectors on them. It is possible however unless your preamp has 4 volt output which it could very well be if using balanced XLR outputs on it, than you might not get full gain output of a PRO amplifier, cause most consumer products could be only 2 volt output which is half and I believe the crown will be looking for a 4 volt signal for 100% gain from it.

This is as plug and play as it gets, you just need another outlet open on the wall to plug the new amp in, and another pair of balanced cheap XLR cables, and another pair of copper 10 gauge lamp cord speaker cables... It will be damn powerfull that much is guaranteed.