AVS Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
43 Posts
Discussion Starter #1
Hi

I am wanting to biamp my Pardigm's with my new Emotiva MPS2. The problem is that my source (let's say my front left speaker) has one RCA out, and I need to feed it to two mono blocks. Are there any cables out there that go one end RCA into two end RCA? And are they any good?

Thanks

Riney
 

·
Registered
Joined
·
596 Posts
you will need an electronic crossover to split your low and hi freq. to your two amps first if you want to bi-amp your speaker.
 

·
Registered
Joined
·
43 Posts
Discussion Starter #3
Ok. That makes sense. Any suggestions on crossovers?
 

·
Registered
Joined
·
1,952 Posts

Quote:
Originally Posted by riney /forum/post/12935377


Ok. That makes sense. Any suggestions on crossovers?


Real bi-amping and the use of active and line-level passive crossovers is best left to experienced enthusiasts and speaker DIYers. Few speakers are suitable for bi-amping because many include EQ elements in their passive crossovers, these are for the voicing of the speaker. Bypassing the passive crossover of such a speaker, as would be done with real bi-amping, would change the intended voicing.


Some modern speakers are set up for "fools bi-amping" a practice which has no benefit other than to let inexperienced audiophiles throw the term "bi-amping" around.


That said there are many fine active crossovers available. The base ART available at Parts Express and some pro-sound shops ar about $100 is a good unit. Other popular brands are DOD, DBX, Rane and Behringer. IME the easiest to use are the DODs and ARTs. Try a local pro-sound store or Guitar Center.


But mind this, if you're going to use an active you need to know that you can bypass the speaker's own passive crossover without effecting the voicing. And you need to know the speaker's crossover point and slope so you can set the active correctly. And it could be that the speaker has an asymetrical passive crossover in which case only a fairly sophisticated active like a Behringer, DBX or EV digital crossover would allow you to match the speaker's crossover characteristics. You could open a can of worms, like I said, bi-amping is best left to the experienced enthusiast.


Regards


 

·
Banned
Joined
·
20,735 Posts
As tom mentioned, active biamping is a very complex undertaking if you're doing it yourself. Most systems that are designed to be actively biamped sell xovers for this purpose that are designed for the speakers in question that you place prior to the amplifiers. For passive biamping, all you need is a y-cable, which you can purchase anywhere for very little, including radioshack. The merits of passive biamping are dubious.
 

·
Registered
Joined
·
1,952 Posts

Quote:
Originally Posted by ChrisWiggles /forum/post/12939644


The merits of passive biamping are dubious.


Chris---With respect, I submit that the benefits of passive bi-amping as defined by the old school are almost equal to the benefits of active bi-amping. I mean using passive filters at the line level between preamp and amps as shown in the diagram in my post. This passive bi-amping goes back to the 1950s at least.


Sad to say the practice of bi-amping has become so full of disinformation (thanks to technically and historically ignorant writers in hi-fi and HT publications) that discussions of it have a hard time setting definitions much less discussing merits. Especially when grouchy old pain in the ass hardliners like me are around.



Kind Regards
 

·
Banned
Joined
·
20,735 Posts
Oops, terminology confusion. When I said 'passive biamping,' I was referring to what you called "fools biamping," just running a Y cable on a full range output to two amps each driven full range to the speaker. This is what I find most people mean when they say "passive biamping" because it uses two amplifiers driving the passive crossover sections of the speaker separately. On the other hand, active biamping would remove the passive crossover at the speaker, and add a crossover prior to the amplifiers. That's the meaning I was intending.
 

·
Registered
Joined
·
1,809 Posts
Can somebody explain to me why having the crossover before the amps, rather than after the amps, makes any real difference? Either way the amp is not making any power if the cross over is not letting it through. Just curious.
 

·
Registered
Joined
·
1,952 Posts

Quote:
Originally Posted by dknightd /forum/post/12941492


Can somebody explain to me why having the crossover before the amps, rather than after the amps, makes any real difference? Either way the amp is not making any power if the cross over is not letting it through. Just curious.


One of the benefits is that the amplifier driving the tweeter gets no low frequency signal, as a result the amp doesn't have to work as hard. You also do away with the insertion loss of speaker level passive crossovers and the effects of reactive components at the speaker level. Some people report better dynamics and less distortion overall when using actives, I'm one of them. On the other hand my best speakers use regular speaker level passives and I leave them alone because the crossovers contain EQ needed for proper voicing.


Another benefit of real bi-amping is that you can mix flavors: many horn speaker enthusiasts use stiff, powerful transistor amps on their woofers and low powered tube amps on their treble compression drivers. Thus the enthusiast tailors the "flavor" of the amplifier to the flavor of the driver. And since the compression drivers are often 10-15db more sensitive than the woofers there's no need for an amp with as much power as the woofers need.


One of my hi-fis is a bi-amped rig with 98db efficiency Altec woofers driven by a QSC 180wpc amp but above 1200hz the 110db Altec compression drivers are driven by a 30wpc Teac T-Amp. The active crossover is an ART.
 

·
Banned
Joined
·
20,735 Posts

Quote:
Originally Posted by dknightd /forum/post/12941492


Can somebody explain to me why having the crossover before the amps, rather than after the amps, makes any real difference? Either way the amp is not making any power if the cross over is not letting it through. Just curious.

It's an enormous difference. The crossover before the amp means that the amp is only amplifying a portion of the audio spectrum. The amp dedicated to the HF for instance, has greatly reduced strain on it because it is not amplifying any low frequencies. This keeps any strain of distortion when there is loud passages especially with lots of bass from affecting the sound quality, or driving an amp into clipping and damaging the HF drivers. In such a situation you could be clipping the hell out of the LF amp, and the HF amp wouldn't even be involved in any of that and the tweeter would be getting very pure and HQ amplification without much or any strain at all.


On the other hand if you're driving the amps full range into passive crossovers in the speaker, you don't get any of that benefit.
 

·
Registered
Joined
·
1,809 Posts

Quote:
Originally Posted by ChrisWiggles /forum/post/12948599



On the other hand if you're driving the amps full range into passive crossovers in the speaker, you don't get any of that benefit.

This is the part I do not understand. If the passive crossovers in the speakers are preventing them from taking energy at some frequency (lets say LF) then the amp is not actually putting work into amplifying these frequencies are they?

Sure they might be fed these frequencies, but if the load is not drawing current then the amp is not really doing any work. Is it? Perhaps I'm confusing the act of amplifying voltage with the amp having to actually deliver current. No current means no energy, but, it would still be amplifying voltage.


Personally I prefer one big amp, but have always wondered what is so bad about passive biamping.
 

·
Registered
Joined
·
596 Posts

Quote:
Originally Posted by dknightd /forum/post/12948725


This is the part I do not understand. If the passive crossovers in the speakers are preventing them from taking energy at some frequency (lets say LF) then the amp is not actually putting work into amplifying these frequencies are they?

Sure they might be fed these frequencies, but if the load is not drawing current then the amp is not really doing any work. Is it? Perhaps I'm confusing the act of amplifying voltage with the amp having to actually deliver current. No current means no energy, but, it would still be amplifying voltage.


Personally I prefer one big amp, but have always wondered what is so bad about passive biamping.

The load will be the capacitors and chokes in your passive crossover. There is nothing wrong with passive bi-amp but to me this is a waste of energy and money. Active bi-amp is the way to go but a lot of people may or may not have any benefit again depending on your setup, when you are talking about a couple thousands of watts system going bi,tri or even quadruple amp is the way to go for sure because your amps are not trying to amplify all the freq so better transfers of power direct to your speakers.


For my self i do have a bi-amp setup for my front channel on my surround and i will never go back to one amp even if my brother in law thinks i'm crazy hee hee(my speakers have 104 db/watt sens), for the rear well i cannot justify bi-amp and one Bryston 4B is enough anyway for me
.
 

·
Registered
Joined
·
17 Posts
Asides from using two amps is your example of "fools bi-amping" really that different from bi-wiring.


I have my fronts bi-wired mainly because when I bought the speakers a number of years ago the dealer sold me cables set up for bi-wiring. I have listened to the system both ways and really hear no difference between single vs bi-wiring. I would expect that "fools bi-amping" would also not show much of a difference either, though i have never tried it.



Debra
 

·
Registered
Joined
·
43 Posts
Discussion Starter #14
I want to thank all of you on educating me. I am going to stick with mono amping.
 

·
Premium Member
Joined
·
1,604 Posts
Just get an Earthquake Cinenova Grande 5 channels with built in adjustable crossovers on each channel, it will still run your center and your mains will stand a good chance of getting toasted with 600w per speaker (300 per channel), aouch. I would drill into the processor volume knob and chassis and put in tiny pins to limit the volume, laugh on
 
1 - 16 of 16 Posts
Top