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Bi-Amp Questions


rplace

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I have an old Denon AVR 3600 collecting dust. It has 5 X 110 watts. I also have a pair of split LaScala LSIs. I've never bi-amped anything but with multiple channels of power and speakers already split between the high and low sections I got to wondering if bi-amping is something I could do easily just as a sort of side project. What say you all and where do the crossovers come into play in this picture? Surely it can't be as simple as feeding the LF section one channel of the amp and the HF the other could it?

 

Currently the LSIs are being fed by a Sonic Impact Super T-Amp. Just feel the need to change things up a bit. Any suggestions?

 

 

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Real bi-amping requires an electronic crossover. 

https://dbxpro.com/en/product_families/crossovers

223s_Front_Large_full_width.jpg

In your case this should work. Set the crossover point to 400 and remove/bypass the LF section of the crossover.  The more common use (and the way I use it) is to drive a pro sub below 100 Hz and keep the mains' woofer motion to a minimum and to get more power into the "system".  Your benefits will be very small, but you will be able to get more power into your LSIs, and vary the levels between LF and HF sections.  Be sure to get one that has phono ins/outs.  If you have a crossover later than a Type AA, you probably should put a 20 watt, or higher resistor across the output terminals for the woofer in the crossover, or remove the connection from the input to the woofer section of the crossover. 

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Isn't it possible to do it passively using the crossovers in the speaker? I'm not against an active crossover network, but I think if I was going that route I'd probably have a dedicated amp for each not be trying to repurpose an AVR. FWIW these LSI LaScalas are in my garage, not my main listening location. Wanting to use what I have and play around a bit.

 

As a side note I have a pair of Altec 511b horns 2 inch to 1 inch adaptors and an extra set of Khorn tweeters. I was sort of hoping to build a second top section for the LSI so I could easily swap them out and hear the differences between the two horns. Any ideas greatly appreciated.

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49 minutes ago, rplace said:

Isn't it possible to do it passively using the crossovers in the speaker?

definitely.  if you have all the stuff laying around, why not try it out?

 

if you had two physical amps, using one amp per speaker would be called vertical bi-amping vs using one amp for the woofers, one amp for the tweeters, which would be called horizontal bi-amping.  active vs passive depends on your crossover use...  I'm not sure what you'd call it with a single multi-channel amp acting as a bi-amp configuration, but it sounds like a fun experiment. 

 

i'd imagine you could use the Denon to cross each amp channel separately, to create an active bi-amp configuration.

 

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Yea that is more along the lines of what I was thinking. One channel of the amp each for:

Right-LF Right-HF

Left-LF Left-HF

 

I figured that would use 4 of the 5 channels. I'm having a hard time seeing how the multi channel receiver designed for HT would actually function as two amps in a vertical or horizontal bi-amp set up like I've read about many years ago. I also have a Carver preamp/tuner laying around unused. Maybe just have the source material go to the Caver Pre then split the left/right with RCA 'Y' cables to Left front, Right front, Left rear, Right rear on the Denon AVR using it strictly as an amp? Getting complicated fast. Hopefully somebody has a better solution.

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whoa, actually, looks like you ALREADY have secondary bi-wiring speaker terminals built in.

https://www.manualslib.com/manual/38289/Denon-Avr-3600.html?page=10#manual

 

i was imagining "tricking" it by sending the main speaker leads to the LF, and surrounds for the HF, but you may already have a speaker configuration option that would work.

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On 11/7/2017 at 4:01 PM, rplace said:

Yea that is more along the lines of what I was thinking. One channel of the amp each for:

Right-LF Right-HF

Left-LF Left-HF

Your Denon AVR 3600 does not support bi-amping.  I understand your logic of wanting to use all the amp channels available but If you try to use them that way the wrong signals (not just power) will be sent to the various drivers.

 

I recommend you do NOT do this.  The AVR3600 simply was not designed to be used that way.

 

EditI just read the link to the manual that @isotopesope provided.  Because your AVR is older, it looks like there is some confusion about the verbiage.  My  Marantz 6011AVR is bi-amp capable and it is specifically supported in the AVR's setup.  Bi-wire is another concept where the single output on the AVR is sent by two sets of wires to the HF and LF of the speakers.

 

But the manual link shows how to do exactly what you are talking about, using the outputs to wire directly to HF and LF inputs on the speakers.  If your manual supports it I feel a lot more comfortable about it being used.

 

Quote

6 pre-out jacks
Multi-room, multi-source with A/V ouptuts
IS programmable remote control
On screen display
Auto preset FM memory
Dolby Pro Logic decoding in digital domain
Dolby Digital (AC-3) decoding
Bi-wiring front (L/C/R) speaker terminals
DDSC digital
Record output selector
80 Hz subwoofer crossover frequency
"S' video inputs & outputs
RF demodulator for AC-3 laser discs
10 analog inputs including phono
110 Watts x 5
Cinema EQ
5 channel stereo

 

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13 hours ago, isotopesope said:

whoa, actually, looks like you ALREADY have secondary bi-wiring speaker terminals built in.

https://www.manualslib.com/manual/38289/Denon-Avr-3600.html?page=10#manual

 

i was imagining "tricking" it by sending the main speaker leads to the LF, and surrounds for the HF, but you may already have a speaker configuration option that would work.

 

Who would have thought, RTFM I guess. Thanks for noting that. It's been in a cabinet for a long time. I've probably not looked at the back of that receiver in a decade. Did not even know the extra binding posts were there.

 

I guess my only remaining question is the LaScalas themselves. The HF an LF sections are separate for easy tear down and transport. Currently I have a + and - speaker wire running into the speaker and a short set of wires with banana plug connects the HF and LF sections. I'm guessing there is one crossover inside the LSI so the signal goes something like this

Source>>Speaker Wire>>Bass Bin>>Crossover>>Split out to HF and LF as necessary.

 

If I run two sets of wires from the amp to each part of the LSI can I damage the speaker. Seems like one section of the speaker will not be utilizing the crossover and that point. Am I overthinking this? Is it possible that each cabinet has it own crossover filtering out the necessary parts of the signal?

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Isn't the single crossover in the HF section?  I believe it is, there is no room in the bass horn.  So you'd wire it Amp > HF/crossover, then HF/low out > LF Bass bin. 

 

You could, IF you have a 2 piece crossover, use 2 channels in the AVR (it actually has separate amps for each channel) that are getting and sending an identical signal and connect one to the LF and one to the HF section and get "passive biamping".  I don't think you have a 2 piece crossover. 

 

As the others have indicated, your AVR may have an internal electronic crossover, allowing you to biamp your LSIs. 

 

Since you have 511Bs, you should really try to get a pair of 902s to use as squawkers.  The 902 will need an 18 dB/oct high pass at 500 Hz, and you will not need a tweeter.  I have a crossover design for a 902-8B/511B crossed at 1k from a Peavey FH-1 I'll give you.  The crossover includes contouring so you don't need an autoformer, EQ, or an L-pad to match the bass horn.  If you will add corner reflectors to your LSI bass horn it will reach 1k well enough. 

 

See the back corners of this bass horn.  You can cut the corners off of a 2x4 to make them and use sheet rock screws to hold them in place. 

 

 

 

 

MinLaScala.jpg

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2 hours ago, JohnA said:

Isn't the single crossover in the HF section?

Yes it is.  They've used up most all the space in there with the crossover, mid horn and driver and tweeter assembly.  It looks as if they took all those parts and put them in the smallest possible enclosure they could..

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14 hours ago, CECAA850 said:

If I remember correctly, you just cut one wire at the fuse holder to isolate the mid/high from the woofer.

 

I've not looked at the back of the LSIs in a long time. The have "stuff" all around them in the garage. Looking online I think you all are correct the connection is made to the HF section first then the LF from there. So the crossover must be in the HF section. I'm not really keen on cutting anything. Can you explain how this works...in layman's terms please? Looking closer at the Denon manual those "extra" binding posts can be used for the bi-wire or running a second set of speakers in a different room. Same source as the mains not like some where you can play two different sources in different locations.

 

So if it is sending the same signal to both sets of speakers or sending the same signal to the HF and LF frequencies seems like I have what I'm after minus the crossover puzzle. Since the LSIs are split by design I can't be the first person to have dedicated amps for each section can I? Even if that not quite what I am attempting. I'm unclear on how the LF section just gets what it needs. I understand how the HF section would work....signal in and the crossover will only pass what it is supposed to the tweeter and mid.

 

I'd like to do this in steps so I can play around with differences as I go. First I'd like to hook up my larger power AVR to the LSI as is. Next bi-amp or bi-wire finally play around with my 511b horn with same Klipsch drive. If I like the direction things progress I might look into making them 2-way. Long story short I just want to mess around with them in these coming fall month. I've used them as is for a while and like all of us from time to time we just can't resist the urge to fiddle around with things. Again they are not may main source of music so no real worries about making them worse in the sort term.

 

Thanks for all the input so far.

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8 minutes ago, rplace said:

Looking online I think you all are correct the connection is made to the HF section first then the LF from there. So the crossover must be in the HF section.

Yes, input is made to the HF section, and crossover is inside.  Not easy to get to....

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Again, going strictly from memory (which lets me down at times) you can remove the panel that has the speaker inputs on it.  There are 6 or 8 screws.  There's  wires that connect the HF to the LF on the back of those that would need to be cut.  I don't think you'll need to remove the crossover.  If you pull the panel and post some pictures I'm sure we can figure it out.

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I must be dense. I admit I don't know much about electronics or crossovers. At a high level I understand them to filter out different frequencies and let others pass to the various high/mid/low.

 

Forgetting my AVR for the time being. As a purely hypothetical situation lets say I have a CD player hooked up to a preamp and I have two 2-channel amps laying around. Configuration 1 I uses only 1 of those 2-channel amps. And do it like everyone since the dawn of time. CD>>Pre>>Amp (only one)>>Left/Right +/- to left and right speaker, done simple I get it. Now I want (for no other reason than I want to do it and hear it for myself) I want to use the second amp so I have two 2-channel amps. One amp per speaker to feed 1 channel to Mid/High the other to Lows. I keep the CD>>Pre. From the pre I use a Y RCA cable to feed the Left output to channel 1 AND channel 2 of Amp1. Next I do the same with the right output of the pre to feed channel 1 AND channel 2 of amp 2. On to the speakers. I put Amp 1 channel 1 to the HF section of the Left LSI and Amp1 channel 2 to the LF of the Left LSI. Lets stop there. Isn't there a problem with channel 2 feeding the LF section a full signal? No matter what I do inside of the terminal. I'm missing how the LF gets only the frequencies its supposed to get. Again I don't know much about the inner workings of speakers or crossovers. But I think I understand the basics.

 

Thanks again!

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