Bi-amp Existing Speakers???

[LLDeese]

REFERENCE SIX INFINITY SPEAKERS
PRODUCT SPECIFICATIONS
General
Woofer 10" (25.4cm) IMG
Power Rating 35 - 225 watts
Frequency Response 35Hz - 40kHz (+/-3dB)
Mid-Bass Driver 6" (15.2cm) IMG
Midrange Driver 5" (12.7cm)
Tweeter EMIT-R
Nominal Impedance 6 ohms
Sensitivity 90dB (1 watt/1 meter)
Crossover Frequency(ies) 200Hz, 1.5kHz, 4kHz

I have a pair of these speakers I would like to run the two 10 inch woofers with a different amp. Is their any way to make the existing crossovers biamplable, or it is easy to build a crossover to do this?????

I have replaced the mid-bass drivers and the midrange drivers with infinity kappa 4 ohm car speakers. And the ten inch woofers with a kappa perfect 10.1. I have had these speakers this way for two years and no ill effect. And they sound awesome!!!
Thanks,,,,,,,,,,,,,

 

[richie00boy]

Do you mean biwired? Biamp means an individual amp for each. If you mean biwired you have to cut tracks on the crossover to separate out the individual filter inputs. IMO it's not worth it, especially as you have already changed the design by putting in different drivers.

 

[Cal Weldon]

richie, he knows he needs a different amp, he was asking about the XO. IMHO he needs an active XO rather than trying to do it passively. Active gives you so much better control over the system.

 

[Narcisse91]

I think I have that same set of speakers, but they're tucked away in storage temporarily...

If it were me, I would look at eliminating the original crossover and starting from scratch. You removed all the original speakers, so the original crossover may not be doing much for you anyway.

So you've basically got a 10" sub in each one? Along with a midrange and midbass speaker?

 

[LLDeese]

I want to run the 10s with different amp from the other three drivers. But keep the tens crossovered at 200hz and the rest of the system the same. What is a good active crossover???? Or what would it take to build a passive crossover???

Thanks,,always appreciated!!

 

[Cal Weldon]

An easy way to do this is a plate amp to run the woofers and your regular amp to run the rest passively through the old XO. (might work well)

Or you can use the plate and do a custom passive XO for the rest. (my preference)

Or if you don't want two wires running your speakers, use the high level from your regular amp to feed the plate and the high level out will have a built in XO which you can feed to the old XO. (least good but still OK)

 

[DrDeville]

richie, he knows he needs a different amp, he was asking about the XO. IMHO he needs an active XO rather than trying to do it passively. Active gives you so much better control over the system.

What Cal said.

I also strongly suggest you go active, with separate amps for as many drivers as possible--since you're four-way I believe, you could get away with going active three ways, leaving the XO between the top two drivers.

I have heard direct comparisons between systems with active and passive crossovers, and the improvement is spectacular--a huge improvement in clarity and transparency, with little downside, and this was with high-end speakers, substituting for their already superb passive XO.

If you search around, you'll see people raving about this, and the reported improvements are even more dramatic with less expensive speakers.

But now for the specifics.

For the line level XO, I suggest the Behringer DCX2496. PartsExpress has it for $250. It's incredibly flexible--can operate as two or three way, etc. And it sounds good, though pro sound, so not Audiophile Approved. But if you search around you'll find an active community of users and upgrades.

The nice thing with going active is it unburdens the amps tremendously, and makes amplifier quality much less of an issue. So you get get by with inexpensive amps, and upgrade later as the urge hits.

In terms of specifics, i don't know this for a fact, but I'm thinking you can simply disconnect the speakers you want to run active from the passive XO, and replace them with an equivalent resistor connected to the XO's wires for that speaker--e.g. 8 ohms. That resistor doesn't have to be high power, since the active XO should cut out that frequency. It's just there to provide the correct load on the passive XO.

Relating all this to this forum, active XO's are great with fullrange systems, because they allow taking the bass load off the fullrangers, increasing clarity and dynamics.

Hope this helps.

George

 

[pjpoes]

Often if there is a resistor in an inexpensive speakers crossover its part of an L-pad to "pad" down a more efficient drivers, often the tweeters. In better speakers it often can also be part of a zobel network or filter.

Now mind you if you completely eliminate the crossover you need a seperate amp for each driver, and will need to spend quite a bit of time balancing the system. I have read some people like to put a passive 6db per octave crossover on the midrange and tweeters in order to protect them from low frequencies, in the event of a crossover failure, and also to protect them from amplifier turn on thumps, and things like that. I do recomend something like this on your tweeters.

Active crossovers can be good, and yes, they will increase efficiency of your speaker system, however, the majority of active crossovers don't give you the ability to equalize the response, remove peaks, alter the phase, or introduce baffle step compensation. However, in order to benefit from any of this, you would have to be able to measure the response of your speakers in the first place, and have the ability to model these crossovers to compensate for these problems. I have been studying up lately and playing with the software myself to learn to do this with passive crossovers. There are some active crossovers that can do this, but not many, and they are very expensive. The DEQX is an example of one that can do this. You could also design your own electronic crossover and incorporate a lot of these features, but again, not something I could really help you with.

 

[peufeu]

Well basically the strategy is this :

First, you measure the electrical response of your passive crossover on the drivers' terminal.

If you suppose the speaker designer has a clue, which is generally the case, the curve you get is an excellent starting point for your active design.

Then, you get a few amps and experiment with various active crossovers using digital crossover software and a multiway soundcard.

(ie any PC now has 7.1 on the mobo and linux hence brutefir supports it, you know matlab and octave dont you ?)

Once you settle on a crossover curve, you can optimize an analog filter to fit it using appropriate software, and then build it.

Gainclones are good for this because everything except the woofers will be low power, and once you remove the high power loss of the passive filter, the requirements for the amps are quite relaxed.

Have fun XD

PS: don't even think about designing a crossover if you haven't assimilated the basics, ie. Dickason and a few textbooks on filter design... it's very interesting though.

 

[LLDeese]

The problem is I am running the speakers with a STR-DE845 Dolby Digital receiver and want surround sound for movies and gameplay. Would be very hard to use an active crossover with my receiver it does not have any preamp outputs, but for a subwoofer. It would be cheaper for me to buy a more powerful receiver than to worry about active crossovers.

Thanks for all the information,,
I thought it would not hurt to try to get the woofers more power and free up some power for the other three drivers.

 

[richie00boy]

In terms of specifics, i don't know this for a fact, but I'm thinking you can simply disconnect the speakers you want to run active from the passive XO, and replace them with an equivalent resistor connected to the XO's wires for that speaker--e.g. 8 ohms. That resistor doesn't have to be high power, since the active XO should cut out that frequency. It's just there to provide the correct load on the passive XO.

No. If you are going active you ditch the old passive XO altogether.

Relating all this to this forum, active XO's are great with fullrange systems, because they allow taking the bass load off the fullrangers, increasing clarity and dynamics.

Why would you run a crossover on a fullrange speaker? The whole point of using a fullrange is that there is no crossover to much up the phase response. Do you just mean adding a high-pass filter to cut off the sub-sonics?

 

[DrDeville]

No. If you are going active you ditch the old passive XO altogether.

Actually, that's not the case, though a common misconception. Many combinations of active and passive are possible, and beneficial.

Here's an excellent primer:

http://sound.westhost.com/bi-amp.htm

Figure 1 shows the sort of setup I suggested. Both you and the thread starter might find it informative.

Why would you run a crossover on a fullrange speaker?

There are a number of benefits, particularly in using a woofer to unburden the fullrange of sub-vocal frequencies:

One is reduced doppler distortion, a garbling effect on higher frequencies, caused by motions to reproduce bass notes.

Another is reduced distortion due to less overall excursion.

Another is greater dynamic range.

The whole point of using a fullrange is that there is no crossover to much (sic) up the phase response.

Active crossovers avoid some of the pitfalls of passives, and offer the benefits above. Personally, I prefer fullrange coherence in the vocal range and above, along with dynamics and slamming bass. You may prefer differently.