PASSIVE BIAMPING BASICS

[BE36]

With the Assumption that I have:

1) ALK Crossover that can Biamped

2) McIntosh Mc240 Mids & Tweets

3) Adcom 535 for bottom end

Would hooking up a Low Pass Filter, Bryston 10b, be a realivily simple event? (seeting the Cross over at 700hz, Test CD and My Sound presure meter to match the volume and we are done?)

Do I have to be concerned with any phase or time delays, etc?

The Mc240 is a great amp and much better overall than my Adcoms but I am looking for my cake and eating to, Crisp Low End with great mids and Highs.

Bobs Cast Woofers? VRDs any other suggestions?

[Coytee]

I'm not an expert nor did I stay in a Holiday Inn Express last night however, I am biamping.

I think if you want to biamp correctly, you are going to need an active crossover after your preamp. I too own some ALK crossovers that had some kind of strap on them. They're in my LaScalas (I bought his 5800 so I could make them 3-way).

There might be some way to split the signal and put parts in the path to truncate the HF or LF...but I think without an active crossover you are STILL going to be sending full signals to your amps and they're going to be sending full signals to each leg you are trying to create here UNLESS you have the active in there dividing the signal up prior to your amps.

Does that make sense? In other words, as I perceive you to be saying, you are going to have a full signal go to your amp(s) and a full signal OUT of your amps into each leg of this crossover. At this point, each leg is getting a full amplified signal from your amps and you might put other parts in there (low pass...but honestly, that talk is foreign to me) anyways...if you put this filter in there you are intending on beating the signal into submission at the crossover input.

The amp however STILL has to do all the work of creating the full signal.

If you put an active PRIOR to the amp, you now have one amp who is only working from 0-700 hz and the other amp working from 700 to 'infinity' hz and the work load on both amps is now lightened.

I'm sure someone else will come along and give you an exact answer in 4 words or less []

[Deang]

I suggest you read the manual that Al sent with the networks. If you built the networks yourself, you can download the manual from his website.

[BE36]

I am not an Electrical Engineer I was probably a litttle to general whe when I said Low Pass Filter. I mentioned the Bryston 10b which would be an active "Spilter" between my Pre and Amps.

Is a Bryston required? Does a Dbx 223 do the job?

I would pay a forum member to make a 700hz Splitter that was designed to by transparent or assembly one of the kits that are avialible. (I do all of my own plumbling and electrical but I have never been taught or learned on my own soldering electrical connections.

[bigrfish]

Google is your friend.

[nola]

BE36

I have some similar gear and an idea similar to yours. I have KHs and LSs, late 70s. Recapping 1 AA network with Sonicaps from Bob Crites. These will be used on the LSs. I will get ALK Unis for the KHs. I now have 2 MC240s, each with different tubes, but with similar sound (only use 1 currently).

My original project idea was to actively biamp the KHs. I also have Adcom amps: 535, 2535, and a 555. None being used currently. (Post Katrina, things were a mess here)

However, I have read many postings discouraging this and no-one I have talked to over the phone, etc. has encouraged it.

In brief folks say, don't bother biwiring or passive bi-amping; active bi-amping on the Khorn has left many feeling that they spent a lot of time and money for little or no improvement. Perhaps due to the high efficiency of the Heritage line, most any size amp (above say 3 watts) is plenty for any non commercial space / venue.

I have to remember to ask folks about this next week in Indy.

Perhaps we should chat. Are you going to Indy next week? If not, lets trade numbers by PM.

Thx

[Coytee]

Nola, as I understand it... if you were going to do your Khorns "right" you would actually have to tri-amp them, not biamp them (each driver with its own amplified channel)

I'm thinking there are only one or two people who are actually triamping Khorns (Maron I think and???)

So, it's not something that many care to deal with the tripling of amps and the extra cost involved there. I'd say, especially if you already have enough amplifiers, get a decent 3-way active on ebay and give it a whirl. If you don't like it, yank it and go back to stock.

I would also speculate that you could biamp with Khorns by putting one amp to the woofer and the other channel to the crossover so the crossover would deal with the midrange and HF. You would want to be able to time align the drivers and I don't know if aligning the midrange/tweeter (via the passive idea) is good enough or if you'd have to align them both to the woofer for 'best' results.

The bottom line as I see it is, most people use the Khorns as is and live with it as good enough, rather than try to squeeze the last ounce of performance out of them by triamping and dealing with the additional issues and expenses triamping involves.

I'd also speculate that if you walked into two identical rooms, one with passive Khorns and the other with time aligned, triamped Khorns that you'd be able to tell the difference. The real question would then become, is the difference in sound, worth the cost and hardware issues to achieve? I think most people get scared (wrong word?) away by that and decide the answer is no.

I was done above, but thought of something else to add...

The time aligned Jubilees sound better in my room at 10' away, than the extreme sloped Klipschorns that I had in the same corner. For them to sound their best, I actually discovered I had to be 20/30' away. It took the installation of the Jubilees and some months of hearing them before I finally stumbled onto what I think is the reason why.

Khorns were 3 way and took some time (therefore distance) for each driver to meld into a singluar sound bubble. The Jubilees being 2-way automatically helped that cohesion of sound happen sooner (therefore closer) AND add in the fact that I can time align them and presto... the sound is coming together VERY quickly with the Jubilees into a single bubble of sound. Much quicker than the Khorns, therefore, they Jubilees sound significatntly better in the same room as the Khorns because the sound is more coherent at this distance.

Make sense?

[Colin]

Like everything else with Klipsch, the use of two simultaneous amplifiers on super-sensitive loudspeakers, like the Reference series or big ole horns is NOT as crucial as typical power hungry cone loudspeakers. There is also a time delay issue with bi-amplification, which pertains more to cone drivers that constant directivity horns.

Paul W. Klipsch himself said that all the Khorns need is a good 20-watt amplifier. Except for a few posts, active bi and tri-amping Khorns is not as popular as upgrading the drivers and the crossovers.

If you “dual-amp” your big ole horns WITHOUT an active electronic crossover passive dual-amplification - each amplifier receives a full range signal and clips at the same point it did with only one amplifier hooked up to the speakers. The distortion of the high frequency (HF) horns masks distortion from the low frequency (LF) amplifier, when it is clipping. This means that if you use a 10-watt HF amp with a 50-watt LF amp it would take 400-watts to play the same level undistorted through the passive crossover!

I matched tube amplifiers with a 40-pound, Class A, solid-state amplifier rated at ten times more power. I use the delicious sounding tubes on the mid and high horns, with the cement amplifier on the bass bins. Maximum power at clipping on the Bottlehead Paramours is 6-watts. Clipping on the Pioneer M022 is 60-watts. I think this power ratio is important to balance loads in a passive dual amplifier configuration. Otherwise you get some nasty balancing issues, which are best resolved by an active crossover. Using active 3-way stereo crossovers however, is more expensive and tricky to get just right.

Passive amplification with dual amplifiers sounds better for me, since the bass bins are driven by my massive Class A amplifier with excellent impedance control. Yet, I am NOT getting the full benefits of dividing the signal ahead of the amplifiers. It is more like driving my big ole horns with a sweet and powerful sounding 200-watt amplifier – at a quarter of the price.

[SWL]

I was driving my power hungry RF-7's with a Crown 475 watt amp. While the power of the pro-amp certainly made the 7's kick ***.....I could never get the HF's to my liking. They were never clear enough......and added significant noise to the system.

At an attempt to remedy this, I left the 475 wpc Crown amp on the LF's and a vintage Harmon Kardon 430 on the HF's in a passive bi-amp configuration. With the ability to adjust the gain controls on the amps running the lows and the highs......this did the trick. 475 watts on the lows and only 30 vintage watts on the highs. The 30 watts on the highs cranks just as loud as when 475 watts was on the highs......but sounds better.

Some say that passive bi-amping or "Fool's bi-amping" is a waste of time because it doesn't have anything scientfic to back it up. My ears have told me otherwise. []