I have a set of MB Quart QM340CX which is separated 3-way speaker system comprising 1” tweeters, 5.25” midranges, 10” woofers, and 3-way passive crossover networks. I also have a pair of 8” KEF KAR 200B subwoofers. I plan to use them with a 5ch amplifier; Soundstream Reference 405. The 405 can be used in 3 channels mode, by bridging ch1 with ch2, and ch3 with ch4. Anyway, the midranges and tweeters will be installed at the front doors and the subwoofers are planned to be installed on the rear parcel. Because the MB Quart subs utilize PASSIVE crossovers while the KEF subs will receive filtered signal from the 405’s built-in ACTIVE crossovers, I wonder if installing those 8” KEF and 10” MB Quart on the same rear parcel, will the sound that is formed by different signal interfere with each other and causes bad sound?
I wouldn't expect any problems with the sound for the two different woofers but you will likely have some peaks or dips as their phase will be shifted from the 8 to the 10". I doubt that it will be a problem.
Do you have to use the passive crossovers for the Quarts? Why not use active crossovers for all of the speakers?
Do you have to use the passive crossovers for the Quarts? Why not use active crossovers for all of the speakers?
Yes, the 10” woofers in the Quart’s system are attached with the passive crossovers. It requires modification to delete them from the woofers which may be undesirable for me. However, IIRC, the passive crossovers have relatively low x-over point of around 120-200Hz. So, is it possible to set the active crossovers that feed the KEF at lower frequency such as 75Hz in order to avoid phase interference?
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After inspecting the MB Quart’s, I think it should not too hard to remove the passive crossovers from them, simple 4 screws under the label sticker and desoldering the terminals. I could now use the active crossover with them. Thanks @Perry Babin for the idea.
There’s a new way I could think recently. I’m not going to use the KEF any longer, because they’re actually being used in my home DIY speakers.
Anyway, I also have a single unit of ADS RS10 unused. What if I would install it together with that pair of the MB Quart. Yes, the rear parcel of my car will be installed three subwoofers there, two 10” MB Quart’s with a 10” ADS in the middle of them. Since the ADS has dual voice coils, so connect each VC to each MB Quart in parallel, is it possible? The total impedance now may be lowered to about 1 Ohm. But thanks to the Soundstream 405’s, it’s capable of driving 1 Ohm load. Is this idea interesting and acceptable?
Anyway, I also have a single unit of ADS RS10 unused. What if I would install it together with that pair of the MB Quart. Yes, the rear parcel of my car will be installed three subwoofers there, two 10” MB Quart’s with a 10” ADS in the middle of them. Since the ADS has dual voice coils, so connect each VC to each MB Quart in parallel, is it possible? The total impedance now may be lowered to about 1 Ohm. But thanks to the Soundstream 405’s, it’s capable of driving 1 Ohm load. Is this idea interesting and acceptable?
Are you referring to removing all passive crossovers from the system?
If you have 12dB/octave crossovers, you cannot drive signal into them if there is no speaker connected to it. If you go full active and the passives aren't used at all, no problem.
You could try the 3-sub option. I don't see a problem with it. If you drive it really hard, the 405 will likely run really hot in 1 ohm. I'd add a fan to help keep it cool.
If you have 12dB/octave crossovers, you cannot drive signal into them if there is no speaker connected to it. If you go full active and the passives aren't used at all, no problem.
You could try the 3-sub option. I don't see a problem with it. If you drive it really hard, the 405 will likely run really hot in 1 ohm. I'd add a fan to help keep it cool.
No, remove only those in the MB Quart sub/woofers.
The midranges and tweeters will retain using passive crossovers.
The system now would be like this:
Amplifier: Soundstream Reference 405
Front speakers: Boston Acoustics Pro 5.0
Rear speakers: None
Subwoofers: MB Quart QM340CX
Is the woofer crossover 12dB/octave or simply an inductor?
How did you plan on bypassing the woofer crossover?
How did you plan on bypassing the woofer crossover?
However, there’s a new problem. My car has only 4x6” holes for front speakers on the dash. So, I might only be able to install the Boston’s tweeters there. And for the 5.25” Boston’s woofers, they would be installed on the drilled holes at the bottom of the front doors. The question is, is the distance between tweeters and midranges matter? I know it should be matter in home audio, but I’m not sure for car audio because, in my opinion, car speakers might receive a compromised or more flexible design compared to home audio speakers.
Yes, it’s 12dB/octave crossover.
Bypassing the woofer’s crossovers will be performed by removing 4 screws that attached the magnet to the crossover, see pictures in post #3, and desoldering wires from speaker’s terminals. That’s all.
I don't know the crossover circuit but if the input terminals will drive the woofer's 12dB/oct crossover with the woofer disconnected, you must disconnect the woofer's crossover. Removing the series inductor may be the simplest.
The same thing applies to any 12dB/octave crossover. If there is no speaker connected to it, it cannot have signal driven into it.
The same thing applies to any 12dB/octave crossover. If there is no speaker connected to it, it cannot have signal driven into it.