This thread was merged with a second of the same title and content.hi all
I want to add a single/mono subwoofer to the two satellite speakers I just built.
Ideally, all three speakers would be powered by the same amplifier, via a passive crossover, split at ~ 100 hz.
I understand the theory and application behind a "regular" 2 way, stereo crossover, eg two tweeters and two mid bass/subwoofer drivers, but can't visualize what I'm after.
Any help or pointers would be much appreciated.
Thank you
JP
https://www.diyaudio.com/forums/multi-way/
The sticky thread right at the top is a good place to start your education.
If you want a single subwoofer you're going to need a 3rd amp channel. You can't tie the outputs of two amplifier channels together without risk of damage. However not much risk of just taking the sub off one channel alone. Not usual that recorded media have severly separated channels in the 300 hz & below band.
However, if one has bought a 3rd amplifier channel, it is cheaper to do the filtering in the analog line level realm before the amp instead of after the amps with expensive crossover components. 3 channel amps sold these days often have the sub filter and mixer built in. If you have a smart phone, read about DSP's that are programmed with such. If not, op amp tone filters and mixers are less expensive than a couple of 50 vac rated microfarad caps and some millihenry coils. Check the prices of crossover components at parts-express for confirmation of this fact.
The sticky thread right at the top is a good place to start your education.
If you want a single subwoofer you're going to need a 3rd amp channel. You can't tie the outputs of two amplifier channels together without risk of damage. However not much risk of just taking the sub off one channel alone. Not usual that recorded media have severly separated channels in the 300 hz & below band.
However, if one has bought a 3rd amplifier channel, it is cheaper to do the filtering in the analog line level realm before the amp instead of after the amps with expensive crossover components. 3 channel amps sold these days often have the sub filter and mixer built in. If you have a smart phone, read about DSP's that are programmed with such. If not, op amp tone filters and mixers are less expensive than a couple of 50 vac rated microfarad caps and some millihenry coils. Check the prices of crossover components at parts-express for confirmation of this fact.
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There's your best advice.
Components for a passive crossover at 100 Hz will be large and expensive. Passive crossovers are not straightforward and their ill effects will be greatly exacerbated by using one at such a low frequency. Plus they'll waste lots of power and give your amplifier fits.
It is so much easier to build a precise active crossover with predictable phase shift. You will achieve much better results and the power from the amplifiers will be applied in a much more efficient and effective manner.
Components for a passive crossover at 100 Hz will be large and expensive. Passive crossovers are not straightforward and their ill effects will be greatly exacerbated by using one at such a low frequency. Plus they'll waste lots of power and give your amplifier fits.
It is so much easier to build a precise active crossover with predictable phase shift. You will achieve much better results and the power from the amplifiers will be applied in a much more efficient and effective manner.
All excellent/reasonable advice. Just what I was looking for. Thank you.
I had considered the subwoofer plate amps, but somehow convinced myself, that feeding my precious tube amp output through there, was sacrileges
I should reconsider that ...or look at the active crossover/before amplification route.
I had considered the subwoofer plate amps, but somehow convinced myself, that feeding my precious tube amp output through there, was sacrileges
I should reconsider that ...or look at the active crossover/before amplification route.
Dear bankschreiner,
You must use two separate amplifiers if you want a stereo system, and this is irrespective of sub-woofer count.
All the best.
I had a passive crossover sub with two 10" woofers connected by speaker input to my bookshelf satellite speakers. the sound was lackluster at best. I built a new sub enclosure with a 250 watt plate amp and reused the two woofers as a powered mono sub. The system came alive, forget about a passive crossover sub. Feed a pre-amp signal to a plate amp with active crossover and drive your satellites with your stereo amp.
Firstly, a "single stereo amp" is a pair of amps, as in "two separate amps in one box". Since stereophonic sound pertains to two independent channels (L, R), it mathematically requires two separate amplifiers and this is true whichever way you look at it. Thus, there is no way the left satellite, right satellite and the sub are all running from the same amplifier. The OP must improvise.
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Here's the late W. Marshall Leach Jr.'s 1999 sub sat project using one 12" dual voice coil MCM speaker. This speaker has relatively low mass, adequate excursion and meets its specs. It's currently around $47. In the past I've seen it for half that figure. Look for coupons to use with Newwark.
Main Article look at the links within it for various details
A Three-Way Satellite Loudspeaker System
Crossover
http://leachlegacy.ece.gatech.edu/satspkr/satspkr4.pdf
12" dual voice coil woofer from this project (meets specs !)
https://www.newark.com/mcm-audio-select/55-1465/woofer-12-dual-voice-coil/dp/34C6021
You could source the 5mH inductors from Parts Express at a low price
Dayton Audio 5.0mH 18 AWG I Core Inductor Crossover Coil
And by "one amplifier" - these days that would be easy with many little 3 channel class D amplifiers
such as those which use TPA3116D chips.
https://www.amazon.com/FX-AUDIO-Blu...mplifier&qid=1617162439&s=electronics&sr=1-11
Main Article look at the links within it for various details
A Three-Way Satellite Loudspeaker System
Crossover
http://leachlegacy.ece.gatech.edu/satspkr/satspkr4.pdf
12" dual voice coil woofer from this project (meets specs !)
https://www.newark.com/mcm-audio-select/55-1465/woofer-12-dual-voice-coil/dp/34C6021
You could source the 5mH inductors from Parts Express at a low price
Dayton Audio 5.0mH 18 AWG I Core Inductor Crossover Coil
And by "one amplifier" - these days that would be easy with many little 3 channel class D amplifiers
such as those which use TPA3116D chips.
https://www.amazon.com/FX-AUDIO-Blu...mplifier&qid=1617162439&s=electronics&sr=1-11
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Agreed that the dual voice coil woofer is worth considering here. Although a single voice coil woofer can be made to work you can lose efficiency mixing the channels properly to prevent damage to them.
A classic sub/sat system should not be that difficult to realize, but as always there are compromises, use a band pass enclosure design for the subwoofer with an upper corner below ~160Hz and a second order electrical LP filter set at about the same frequency.
Look at the early 90's SW200, 300 and 500 sub/sat systems from JAMO, the use single coil woofer in an isobaric bandpass configuration which enables you to use them with regular stereo amps while achieving a compact and simple format.
Look at the early 90's SW200, 300 and 500 sub/sat systems from JAMO, the use single coil woofer in an isobaric bandpass configuration which enables you to use them with regular stereo amps while achieving a compact and simple format.
120 Hz passive crossover, good working, not expensive...
Parasound CX 1002 120Hz Passive Crossover-Audio Advisor
if you insist on one sub, I can find info for passive if you want, I got old article dealing with it
Parasound CX 1002 120Hz Passive Crossover-Audio Advisor
if you insist on one sub, I can find info for passive if you want, I got old article dealing with it
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