So when calculating boxes for a speaker with multiple drivers you get a curve for each driver
One driver will produce -18db of 70hz
The second driver will produce -6db of 70hz
Just looking at curves for each driver
Does this mean the the final product, the speaker will have a curve which sums the bass output of both drivers and will look flatter than each individual curve?
Attached is an example of mark audio alpair 5 gen 3 + peerless 5.25 woofer. Alpair will have its own sealed box which will be encapsulated into a bigger box containing peerless woofer
Red curve is mark audio alpair 5 gen 3 in .5 liter box.
Blue curve is peerless sds-135F25CP02-04 in a closed 3L box.
Green curve is peerless sds-135F25CP02-04 in a vented 3L box.
If I decide to make a complete closed box system will the final speaker bass performance be the sum of red + blue curves?
How to calculate how much bass will be contributed by alpair 5 to final result. Doesn't it ad like 3db to final result. Is it just adding the DB values st a certain frequency?
Reason I decided to keep alpair 5 in closed box is so it could handle more power and not bottom out. I like to have good amount of headroom.
One driver will produce -18db of 70hz
The second driver will produce -6db of 70hz
Just looking at curves for each driver
Does this mean the the final product, the speaker will have a curve which sums the bass output of both drivers and will look flatter than each individual curve?
Attached is an example of mark audio alpair 5 gen 3 + peerless 5.25 woofer. Alpair will have its own sealed box which will be encapsulated into a bigger box containing peerless woofer
Red curve is mark audio alpair 5 gen 3 in .5 liter box.
Blue curve is peerless sds-135F25CP02-04 in a closed 3L box.
Green curve is peerless sds-135F25CP02-04 in a vented 3L box.
If I decide to make a complete closed box system will the final speaker bass performance be the sum of red + blue curves?
How to calculate how much bass will be contributed by alpair 5 to final result. Doesn't it ad like 3db to final result. Is it just adding the DB values st a certain frequency?
Reason I decided to keep alpair 5 in closed box is so it could handle more power and not bottom out. I like to have good amount of headroom.
If a single box is loading multiple drivers, then best IME to find the mean specs to sim with for most accurate approximation.
Hm. Yes complex calculus problem. Wish Isaac Newton was hanging out on this forum.
Whats the problem if I enclose mark audio alpair In a tiny volume of .5L-.6L. just no bass or some other artifacts will pop up. Thinking of using it as midrange/tweeter and tune bass of peerless later..make it ported or sealed. Is this some sort of heressy.. or misuse of the driver that will result in not hearing all of it's might
Was gonna ask how to find port size for 2 different drivers In same enclosure but this sounds like a complex problem to resolve perfectly correctly. Do they just tune port to largest driver in the speaker and ignore midrange movement. Or in a well designed ported speaker they have a separate box with dedicated port for each driver
Whats the problem if I enclose mark audio alpair In a tiny volume of .5L-.6L. just no bass or some other artifacts will pop up. Thinking of using it as midrange/tweeter and tune bass of peerless later..make it ported or sealed. Is this some sort of heressy.. or misuse of the driver that will result in not hearing all of it's might
Was gonna ask how to find port size for 2 different drivers In same enclosure but this sounds like a complex problem to resolve perfectly correctly. Do they just tune port to largest driver in the speaker and ignore midrange movement. Or in a well designed ported speaker they have a separate box with dedicated port for each driver
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So you have 2 different drivers playing in the same frequency band? If they have a different phase response (because their low end is an approximation here and does not include baffle step) then it's anyone's guess as to whether they will sum in unity (if wired in parallel) to provide +6dB (assuming same cone surface area) or even negative.
Also remember - low end extension tools that approximate bass rolloff / extension do not show you what the driver is doing higher in frequency (i.e. the flat line means nothing here). The drivers will continue to sum and may destructively interfere. What is your plan to cross these over further up?
Also remember - low end extension tools that approximate bass rolloff / extension do not show you what the driver is doing higher in frequency (i.e. the flat line means nothing here). The drivers will continue to sum and may destructively interfere. What is your plan to cross these over further up?
Well, in general, as the box size shrinks the Qt rises, ergo becomes increasingly under damped ('peaking', 'rings') in that it starts sounding 'loose' 'flabby', so internal damping must increase to compensate till it gets acoustically too small to put in enough damping, so must resort to electronics to control it.
Yes, again, need to find the mean specs to choose box size, tuning.
Re calculus problem; me and higher math are pretty much mutually exclusive, but I know that for just two drivers I can find the mean of each spec by (spec 1 * spec 2)^0.5, so seems reasonable to me that for three it would be (spec 1 * spec 2 * spec 3)^0.333.
Anyway, simple enough to do the two drivers my way as I know it works to see how each driver sims in this 'averaged' box alignment along with the sum of the two and short of one of our math wizards 'correcting' my three way, believe it will be just as accurate.
Note though that T/S theory peters out at each driver's upper mass corner (Fhm), so ignore any frequency response above this point summed or otherwise:
Fhm = 2*Fs/Qts'
(Qts'): (Qts) + any added series resistance (Rs): http://www.mh-audio.nl/Calculators/newqts.html
Yes, again, need to find the mean specs to choose box size, tuning.
Re calculus problem; me and higher math are pretty much mutually exclusive, but I know that for just two drivers I can find the mean of each spec by (spec 1 * spec 2)^0.5, so seems reasonable to me that for three it would be (spec 1 * spec 2 * spec 3)^0.333.
Anyway, simple enough to do the two drivers my way as I know it works to see how each driver sims in this 'averaged' box alignment along with the sum of the two and short of one of our math wizards 'correcting' my three way, believe it will be just as accurate.
Note though that T/S theory peters out at each driver's upper mass corner (Fhm), so ignore any frequency response above this point summed or otherwise:
Fhm = 2*Fs/Qts'
(Qts'): (Qts) + any added series resistance (Rs): http://www.mh-audio.nl/Calculators/newqts.html
Very important detail I forgot to mention
The peerless 5.25 drivers will be used as a subwoofer. 2 of them connected in series but physically located separately In left and right speaker. Peerless drivers will be playing under 150hz or so. Bass only.
Mark audio I'd probably cut off at 150hz. There is an option in the amp to set high pass filter at 150.
I have a 2.1 plate amp. If you can recommend any other small driver for bass I'd appreciate..I just went based on reviews. 5.5" or smaller driver. Peerless recommended sealed box size is pretty small too. Around 3L.
The peerless 5.25 drivers will be used as a subwoofer. 2 of them connected in series but physically located separately In left and right speaker. Peerless drivers will be playing under 150hz or so. Bass only.
Mark audio I'd probably cut off at 150hz. There is an option in the amp to set high pass filter at 150.
I have a 2.1 plate amp. If you can recommend any other small driver for bass I'd appreciate..I just went based on reviews. 5.5" or smaller driver. Peerless recommended sealed box size is pretty small too. Around 3L.
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Interesting. So basically I go through all parameters and make a virtual driver that is the average of the two. Calculate the box from these averages.
Correct. Frankly, during my active building years I often wound up doing it for all speakers since quality assurance (QA) checks back then was typically +/- 10-15% for Fs, efficiency (mostly before T/S became popular), so using measured specs of just one could get you a 'funny' sounding stereo pair with the room positioning of course aggravating it to the point where I wound up most times tuning each individually in room till folks started moving the stereo around more (different rooms, new homes, college dorms, apts, etc.) at which point I quit building except for helping with big, expensive (horn) designs and/or mostly amateur prosound apps.