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Design for One 10" Sub


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Ok, so for real now. After looking at the specs for my little Panasonic receiver (the right manual this time) I've seen that the receiver puts out 200w RMS @ 3 omh w/ 10% THD and 100w RMS @ 3 ohm w/ 1% THD. I decided on a 10" 200w RMS DaytonAudio subwoofer with a 4ohm SVC.

Box Specs:

Net Volume = 2548 in^3 ~ 1.47 ft^3
Port Area = 28 in^2
Port Length = 29.25 in
Tuning = ~35 Hz
All 3/4" MDF

Transfer Magnitude Graph

D9xbrXL.png

Cone Exurstion Graph

xWU3xdZ.png

Port Velocity Graph

FUBTv7z.png

Front View

dP5KXmH.png

Side View

The black line extending from the speaker cutout is how far back the driver will go.
7i1uGNt.png

The graphs are set with 200w of power. This should be the maximum this sub will see. It will float more along the lines of 100w RMS before rise and all that jazz not taking into account that it will be less than rated due to the sub being 4ohm and the rating at 3ohm. I also didn't take into account the driver displacement when calculating the net volume but figured it's not going to be a whole lot seeing it's a fairly small driver. As for bracing is it really needed in this situation. Not a whole lot of power or sub plus the largest open panel spaces aren't very large. Let me know what you think and thank you in advance for your time.

Note: I would've just updated/changed the title of my previous post but couldn't figure out how to. Oh well.

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I think your design looks fine, though that sub rolls off on the bottom end pretty high.

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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I think your design looks fine, though that sub rolls off on the bottom end pretty high.

Yeah that bothered me too. Tuning it lower helped that a bit and so did playing with the net volume. My problem was trying to get the excursion graph to look reasonable. ~8mm of Xmax isn't very much to work with and although i'll be running below RMS power of the sub most of the time the excursion graph was still getting really close to the limit. When I get off this long mail shift I can try playing around with it and trying to get it to roll off lower. My original design had it starting to roll off at around 35Hz instead of 40Hz. Whatever happens i'm sure i'll still be satisfied with the results. The sub that is currently with the system (the one that came with it) just isn't cutting it. It's a little 6.5" with a cheap cone and little excursion. Pair that with a flimsy box and you have pretty poor output. Anything below ~40Hz is pretty much inaudible and the loudest it will get is, compared to what i'm use to now, still pretty quiet. I'm not expecting this little 10" to be earth shattering but at least better than what I have. This whole problem stems from the fact that the sub output is already amplified and that it uses a damn proprietary connection. I'll have to cut the wire that's connected to the original and connect it to this one's terminals and also make some sort of terminal block for the original just in case I want to ever use it again.

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I played around with different box sizes and port tunings/area and this is what I came up with. Still same basic design I laid out before with slightly different dimensions. Net volume area is now 18D x 13W x 13H (3042 in^3 or just under 1.8 ft^3). Port is 26 in^2 and 33.25 inch long. These are the graphs I got.

The original design is in red and the new design is in blue.

Transfer Function Magnitude:

PSpQIFA.png

The response is a little bit less (just over 1dB at it's "worst" point) but not enough to be noticeable however once the graphs cross each other the new design has up to 5dB more output over the original design.

Cone Excursion

Yl7YRYY.png

A little bit higher than the original but still not too bad. Like I said before, these are simulated to 200w RMS and I probably will never see that so i'm not too worried about the cone excursion as long as it's not crazy high.

Port Velocity

iD64uly.png

Again, a little bit higher than the original but it's still under 13 m/s at it's highest point on 200w.

Does this look a bit better? Questions, comments or concerns?

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Also, what do y'all think of the little sub? I thought it was pretty decent for $72 and i've heard decent things about DaytonAudio's speakers.

Edit: This is the link for the Sub. The link to the spec sheet is on this page too.

http://www.parts-express.com/dayton-audio-dcs255-4-10-classic-subwoofer-4-ohm--295-202#lblProductQ&A

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I agree your second proposed design looks better. Do you have a way to implement a high pass filter (subsonic filter) on your amp? Over excursion below 25 Hz would be my concern.

My experience with Dayton products is they almost always offer really good quality and performance for what they cost. I'd be very surprised if you aren't happy with the performance of that sub. Also Dayton usually measures Xmax of their products using (coil height - top plate thickness) / 2. The mechanical travel of the sub USUALLY is quite a bit more than that, so over excursion MAY not be as much of a concern. Your millage may vary though.

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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There is not a way to implement a high pass filter in the amp but I think one might already be built in. The sub that is with it now can't really take anything below 40hz. Idk of its built into the amp or the sub though.

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A lot of those home theater-in-a-box type subs have a built in high-pass filter, so you may be fine. You could find out pretty easily with a multi-meter and a sine wave tone generator.

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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A lot of those home theater-in-a-box type subs have a built in high-pass filter, so you may be fine. You could find out pretty easily with a multi-meter and a sine wave tone generator.

I would if I had a multi-meter but unfortunately I do not. But, for future reference, how would I test it?

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I would if I had a multi-meter but unfortunately I do not. But, for future reference, how would I test it?

A digital multi-meter is a very cheap and useful tool, you should get one. This one will do the job just fine: https://www.amazon.com/Resistance-Frequency-Auto-ranging-Multimeters-Capacitance/dp/B00O1Q24DA/

To see where the high (and low) pass filters are you would play a sine wave frequency in the middle of the pass band, like 60 Hz. With the subwoofer disconnected you would measure the A/C voltage coming out of the amp. Take that voltage and multiply it by .707. While leaving the volume constant, decrease (or increase) the frequency of the sine wave tone while watching the voltage. When the voltage drops to the value your calculated (original voltage * .707) that is the frequency of the crossover.

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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