Hello,
so I have one Dayton Audio SD215A-88 in my DIY multiway and It is definetly reaching pretty close to the Xmax at about 40W, which is why I'd like to raise the impedance.
So my question is, would leaving only one coil connected change the T/S parameters in any way, should I wire it in series (not optimal as that would give too little power).
The driver has 80W RMS, playing 40W seems to be enough for the mechanics.
It has 2 VC, 2x 8 Ohm.
The box is 130 liter ported enclosure tuned to 28 Hz.
Subwoofer Link: Dayton Audio - SD215A-88 8" DVC Subwoofer 4 Ohm
so I have one Dayton Audio SD215A-88 in my DIY multiway and It is definetly reaching pretty close to the Xmax at about 40W, which is why I'd like to raise the impedance.
So my question is, would leaving only one coil connected change the T/S parameters in any way, should I wire it in series (not optimal as that would give too little power).
The driver has 80W RMS, playing 40W seems to be enough for the mechanics.
It has 2 VC, 2x 8 Ohm.
The box is 130 liter ported enclosure tuned to 28 Hz.
Subwoofer Link: Dayton Audio - SD215A-88 8" DVC Subwoofer 4 Ohm
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At what frequency is it hitting xmax?
I wouldn’t wire just one voice coil. It won’t work properly. Well it changed TS parameters and cits RMS bully around half. Not a good idea. Makes it peaks at resonance.
Only real option is parallel or series.
But I would be thinking more about enclosure volume and what frequencies it’s reaching Xmax and what your doing below tuning point (high pass filter) than anything else at the moment.
I wouldn’t wire just one voice coil. It won’t work properly. Well it changed TS parameters and cits RMS bully around half. Not a good idea. Makes it peaks at resonance.
Only real option is parallel or series.
But I would be thinking more about enclosure volume and what frequencies it’s reaching Xmax and what your doing below tuning point (high pass filter) than anything else at the moment.
You will not be getting more sound out of it than you are getting now, since you are reaching Xmax. Why modify? Just don't open your amp all the way.
While it's a very good budget woofer that box sounds grossly over sized. I've found around 30l tuned to low 30s and they work great. If you got that much size get a few more for it and let the beat pound.
WinISD shows this at 80W power.. I'lll be doing a frequency sweep today on the actual woofer today to see how it performs but it still extended quite far from listening to music and I didn't want to extend it too far. And the frequencies below tuning aren't the problem, seems the amp has a filter built into it for that.. it's the 64 Hz and down to the tuning frequency
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I mean it kind of sounds better with 40W anyway since it's a 2-way crossover and the other 2 mid/high drivers have 40W combined. However it still extends 1.5mm over at 35 Hz..
Would adding a panel behind the woofer help in anyway? I mean if the sound bounces back from it, would it not help control the woofer?
David,
No and no, a 35 Hz low frequency sound wave is 32 feet long, a small panel will have no effect on it, other than a slight box volume reduction.
The excursion your sim shows is almost double the Xmax.
Reducing the power by 6 dB will reduce excursion by half.
That said, the motor (Bl) and suspension limitations of your driver may not even allow it to reach the excursion your sim shows with that voltage input.
Art
Support from Dayton audio told me I could use polyfill inside to help.. doesn't that make the box act even bigger tho?
This a CAD model of the build btw:
It’s not going to solve anything.
Smaller box more power slightly higher tune
Or
Buy another and put that on with it. That should solve a lot of the issues. As it would basically half the box size. And increase Xmax by double at the same time. Feeding 2 80W on that box should make for a much better output.
You would obviously have to WinISD it and change certain port lengths to get the correct tune probably. Not really simulated many ported
I’m a big box sealed max power man myself
Smaller box more power slightly higher tune
Or
Buy another and put that on with it. That should solve a lot of the issues. As it would basically half the box size. And increase Xmax by double at the same time. Feeding 2 80W on that box should make for a much better output.
You would obviously have to WinISD it and change certain port lengths to get the correct tune probably. Not really simulated many ported
I’m a big box sealed max power man myself
Will it make a difference in volume at all tho? Isn't the cone that makes the sound and if it requeres less power to move, it would techically be better for the battery? Or does it requre less power only at lower freqs?
What do you think will happen if I enclose the sub all around except the bottom.. that should add extra back force since the air would have to move down right?
Well thanks everyone for the help, I'll keep the sub at 40W as it sounds better paired with the other 2 drivers at that level than 80W (the sub also plays the lower midrange, and it doesn't sound very good if lower midrange is louder than the higher midrange) and larger excursions still extend the bass more i guess.. I'll do a frequency test on full volume starting from tuning frequency up and if i hear distortion, I'll add 2 panels in the inside and move them further closer to the woofer until the distortion disappears.
I did a bit of simulations in WinISD. What electronics are you using? Do you have any option of adding a highpass filter?
Green line. Vented 130l box without filter. There you can only use 25 watts of power without hitting x-max if you play music with very low base.
Blue line. Vented box 130l box with highpass filter. 4th order 33hz and 1st order 45hz powered with 80 watts without hitting x-max at any frequency. This gives up a higher output from 38hz and up.
Also did it for closed boxes and that is shown by the red and orange line.
SPL
X-max
Green line. Vented 130l box without filter. There you can only use 25 watts of power without hitting x-max if you play music with very low base.
Blue line. Vented box 130l box with highpass filter. 4th order 33hz and 1st order 45hz powered with 80 watts without hitting x-max at any frequency. This gives up a higher output from 38hz and up.
Also did it for closed boxes and that is shown by the red and orange line.
SPL
X-max
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I did a bit of simulations in WinISD. What electronics are you using? Do you have any option of adding a highpass filter?
Green line. Vented 130l box without filter. There you can only use 25 watts of power without hitting x-max if you play music with very low base.
Blue line. Vented box 130l box with highpass filter. 4th order 33hz and 1st order 45hz powered with 80 watts without hitting x-max at any frequency. This gives up a higher output from 38hz and up.
Also did it for closed boxes and that is shown by the red and orange line.
SPL
X-max
Yeah I can make an additional high pass, I'll be semi enclosing the woofer in another box within the enclosure without the box having a bottom panel to see how it sounds, should create more pressure since the air hits the cube and is forced to move down. Thanks for the sim.
I did a bit of simulations in WinISD. What electronics are you using? Do you have any option of adding a highpass filter?
Green line. Vented 130l box without filter. There you can only use 25 watts of power without hitting x-max if you play music with very low base.
Blue line. Vented box 130l box with highpass filter. 4th order 33hz and 1st order 45hz powered with 80 watts without hitting x-max at any frequency. This gives up a higher output from 38hz and up.
Also did it for closed boxes and that is shown by the red and orange line.
SPL
X-max
I'll just make an active filter I guess
Hmm, if this is accurate, I don't think I should use a passive high pass
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