Ok.....so.......I've currently got my two 12" subs hooked up to my two channel amp in stereo mode (one speaker per channel). I did this just cause it was simple.

However.....I've been considering rewiring them in mono (both subs wired in series, and bridged over the two channles of the amp). I have some reason's for wanting to do this........but their based purely on my own logic, not anything I've heard or read, so I don't know if what I'm thinking is true.

But anyway, here are my thoughts:

Running the speakers in stereo, I potentially have two different sets of acoustic information going to each sub. Because of this.....the waves leaving each subwoofer may not always match the wave of the other subwoofer..........perhaps causing distortion and even wave cancellation (ie, troughs meat peaks, peaks meet troughs, bye bye sound wave).

Also....it would seem to me that by running the speakers in stereo, if a certain frequency is being played only through the right channel for example.......I will only be getting half the possible speaker output for that frequency because it is only playing through the right subwoofer.

So........if I run the subs in mono.........I'm thinking all the waves leaving each sub will be the same as the opposite sub.........thus complementary. Also, both subs will be playing all frequencies that I haven't cut out using the low-pass crossover on my amp (frequencies under 100hz).

Audio guys...........please tell me what you think. Is my logic correct here or am I way off? Should I run the subs together in mono mode? Or does it even matter?

Thanks.

KiL

 

my subs have always been done in mono. Its the best way. like you said, the waves could cancel if in stereo. plus, two subs have double the amplitude of one subs, i.e. twice as loud, where as each operating independent may not.

 

I'd buy it. Low hrz sound is largely indirectional, so you don't get alot of single channel thumps (it happens, but not alot) anyway.

 

Well you can only run the subs in mono only if your amp can handle it...Most amps are only stable at 4ohm mono unless you have a specific mono block amp that can handle the lower impedance or a 2 ch amp that is 2ohm stable in mono.

If you are running a sub in stereo they better be in separated sealed chambers. If you have an enclosure that shares the air space, you better run it in mono.

 

yeah.... what they said

 

They are in separate sealed chambers........and my amp is stable in mono down to 4 ohms. Both speakers are wired to be 2 ohms.........so running them in series would create a 4 ohm load..........just fine for my amp.

So......any benefit in wiring them in mono?

KiL

 

Nope....2ohm stereo and 4ohm mono will pretty much be the same power wise...Even if you had it running 4ohm bridge and the bass shifted from the right channel to the left channel, the bass will still attenutate for that length of time when it goes from one channel to the other. Id leave it.. But if you feel the need to try it..try it.

 

Whether or not subs should be in stereo or mono is a widely disputed topic in audio. I dont think there is a universally correct answer. It comes down to what you prefer

--
Cheese

 

I say scrap the whole project, give it all to me, and start from scratch...only real way to get it right.

 

You said...Running the speakers in stereo, I potentially have two different sets of acoustic information going to each sub. Because of this.....the waves leaving each subwoofer may not always match the wave of the other subwoofer..........perhaps causing distortion and even wave cancellation (ie, troughs meat peaks, peaks meet troughs, bye bye sound wave).

I say... Yah but. Unless you but this is gonna happen anyway an any f other then x. If the sound was a single sin wave you could tune the position to reenforce for that frequency. Other then that it does not matter. However you don't want the speakers to be integer distances of 1/4 the diamater or depth of the speaker - you are more likly to get resanace at those distances(and it could be good or bad) so don't do that.

[color=greenAlso....it would seem to me that by running the speakers in stereo, if a certain frequency is being played only through the right channel for example.......I will only be getting half the possible speaker output for that frequency because it is only playing through the right subwoofer. [/color]

Yah but probably not: here is why. If they wanted sound to come out of only one channel and not two it would already be only on one. But because of the nature of sounds it is more likly in both anyway already. But lets say for the point of argument you do want you want. If the same sound is one one channel or in both. If it is one you get x, in 2 you get 2x. So it will not be any relative louder when you put it in the speaker as mono because you are taking the x as apposed to 2x prior to amplification. (assuming the sound was at 0db)

What you are giving [going mono] up is special effectsl In a larger area you can't realy tell ... but occasionly I have noticed on my home sterio that they do split the bass for that feel effect coming from one or the other channel. You might want to try this... humm how to try.

Tells yah all what. I'll make a couple of wav files that have a single, that is only, sin wave @ some low Hz - You guyz tell me: 27? 30? 50? Whats the low ranges of your subwoofers. Or more exact bursts of like a few seconds of the sin.

I can make it the same on both channels.

Make one that is -3 dB (50%) DOWN ON BOTH

And then the same with alternating channels.

Then I will do the same and reverse one of the channels. and make recordings too.

I will also make a recording that says "left left" "right right" but much softer for testing that your left and right works. I think I can do this on Sunday if you can chill that long. Infact I know I can. I have cowmitments between now and then however.

If you need I can send out CD's with this wav burned into them. We can do paypal for the cost of shipping + the disk if you need it (that is don't have a burner).


See if you can tell a diff. I'll not tell you which is which. Just like a b c d or somthing.

If you can tell then you need to keep it sterio. If not doesnt matter.

There will only be sign waves at the low Hz value so no high freq infomation is occuring. You might not even hear it if we pick a value low enough.

I'll make a couple of patterns. Maybe a single waves with space between then maybe 10 seconds of the wave.

I have software and will create this compuationaly. Truly direct digital recording. No analog. No AD/DA. Just some wav files for you to slam onto a CD

So........if I run the subs in mono.........I'm thinking all the waves leaving each sub will be the same as the opposite sub.........thus complementary. Also, both subs will be playing all frequencies that I haven't cut out using the low-pass crossover on my amp (frequencies under 100hz).

Audio guys...........please tell me what you think. Is my logic correct here or am I way off? Should I run the subs together in mono mode? Or does it even matter?

If there is interest in this experement then let me know. I'll have wav files posted to my website sometime sunday late afternoon or night for you to download.

We can do a poll thingy and then like in a week I'll let ya'll know what the results are. That is what ppls said they herd vs what was realy there

I don't want to do mp3 cause I think the compression will give a clue as to what is what cause of the size differences that will occure.

If you want to do this here is what we will need before sunday:

What is the frequency of the sin wavs to test this out. If I pick to low yall will not hear it. So we need the following:

a: What is the low frequence responce of the speakers in a stock xA/xB - I will make a set of wavs with the (value + 3) Hz
b: You gals guys with the subwoofers what exact value should we use for the test. I'll make a set for yous toos.
c: You even interested in this? If five ppl or more are interested in this. (or 3 cows ... cows have much better low freq hearing then ppls) I'll do it.

Then I'll need to set up a results page on the that is this site.

My bet is that ... sorry don't want to distort the results.

As for the ohm questions seems like you gots that right but I don't know....can't think need sleep!

 

if you're wiring your two subs in series, make sure and wire the pos lead from the amp to one sub and teh neg to teh otehr sub.. then link between the + on one to the - on the other..

otherwise you won't get series...

 

what you might get is phase reversal.

which is usualy bad but not allways

 

Audio is pretty simple.

If your recording is in stereo, and your playback is in stereo, with amplification in stereo, and subs running stereo, then you have a fairly acurate reproduction.
net gain = 0

If your recording is in stereo, and your playback in in stereo and you run your amp in mono, it would then cancel out the audio just as your subs would if everything was run in stereo.
net gain = 0

If your recording is one of those BASS CDs and it is mono for the low frequencies, and your playback is therefore mono, and your amps are run stereo and your subs are stereo, they would still be reproducing a mono sound.
net gain = 0

So running the subs in mono does not favor you in anyway.

Now when it comes to the amplifiers themselves. If you run an amp in stereo, it will use the FETs (field effect transistor, the part that actualy does the amplification) to sweep both the positive and negative of the wave. Giving you 100% utilization of the FET. If you run a stereo amp in mono, then one channels worth of FETs run the positive and one channels worth runs the negative sweep of the wave, giving you 50% utilization of each FET. You will gain some output because when you run a 4ohm load across the two channels, it halves the resitance giving each channel a 2ohm load. That theoretically should give you 100% increase in power, but with half the control and half the use of the FET.

Better answer, buy a single channel amp, mono amps are not stereo amps running in stereo, they are single channel. Meaning you get 100% utilzation of the FETs and 100% of the control over that power.
Or, get dual voicecoil subwoofers. That way you can run the voicecoils in parallel and give each channel of the stereo amp a 2ohm load, giving you nearly a doubling of your power.

In all honesty though, doubling your power generally gives you a 3dB gain. Doubling your sound output takes a 10dB gain. You'd have to double the amount of amplification and double the number of subs to gain 6dB, and you still wouldn't have doubled your sound output.

If you want better sound from your equipment, and your equipment is worth of some investment, your best bet is to take it to a professional and have them build you a box. Not just a box either, one that is designed to work with your vehicle. If you buy a box off some sales floor it may look neat, but it may not couple with your vehicle well, you may get standing waves, you may get no gain from the shape of the vehicle. Or the box just might look tacky. Also bee wary of the installer that can hide your sub in some cool location, ask him/her if it will help the sound quality by putting the sub there.

I've done several competition systems, but I take the most pride in the customers that came in and got something that sounded better than they could have dreamed just because they listened to their ears instead of some advertisement. Thats the bread and butter of a good company, word of mouth, happy customers, return customers. Your system doesn't have to be elaborate to sound really incredible, just pay attention to what you are doing, and do it right the first time.