The baffle is mounted on a 3/4 mdf piece, and yes the internal volume of 2.15 is completely different from the total volume with the vent included.
Yes this is designed for a car, and as for the port dimensions i have posted it a bit earlier.
the depth is 33 inches, height is 14.5 and width is 3
That's what I said...
Rick, I don't know what's the point of the OP. Or he is not aware of it, or he wants something he is not expressing /explaining... (possible?!) It's obvious, not with the same enclosure he is being stubborn with.
Many members just leave after the fact...
Another possibility that I did not test is the bandpass. It comes well represented for car audio. It has a 3dB atten. @37/38Hz to 93/100Hz.
The port OP is mentioning for 37Hz tun would be ~90cm...
Maybe OP is in a competition insisting in SPL... I don't know.
In this case is 1.00 m/113.6 dB (max.) witout car gain, for ~800W@3.5 Ohms (theoretical).
Im sorry if I am not being clear with my intensions, but I would basically want to know what is causing such bad efficiency and port turbulence and how to avoid it in the future.
Im actually building the subwoofer for a friend so it will not be used for any competition, im just very confused as to why a 10 inch subwoofer out performed this 12 inch by such a large margin
The SPL test was done at 50hz (Since i was getting more air than loudness at the tuning frequency i just did a sweep and picked the loudest frequency as the max)
You have a very long slot port there, so you have to be making a 90 degree turn at the back of the box, and then another effective 90 degree turn at the internal entrance to the port. If you don't have any 45 degree plates at the corners, it is probably creating a good bit of turbulence at those corners resulting in the large amount of port noise! You need something like this for an effective slot port with turns:
An externally hosted image should be here but it was not working when we last tested it.
(OP) Thanks for the info. 
(Sometimes threads get very long and difficult to follow, as you must imagine...)
Anyway, as you see that's the most difficult driver (type/parameters, there are many like that) that you had to run against. Even his evil brothers S4, D4 are easier to manipulate.
And, as you see, again, that's not a practical length for a port, and it takes all the space inside the speaker. Before we can compare this driver/speaker with another we have to have a good implementation, what is not the case. Did you linked a simulation (made by you) for it already? Did you mention your amp already? Take care.
(Let's make another try, simulation in my computer...)
I'm not used to the specs of this driver but maybe someone can refer to it's stupidly high reference specs like Qts of 1.16 that his very high (and Qes, Qms). Obviously it works in a OB (notice the high Qms) or sealed, not the best in this class too with only like one type Q, not being flexible or responsive to the size of the enclosure.
You might run into other issues like the cone/coil running against the pole plate or getting out of the gap with max. excursion at lower freqs. if drived to hard (<25 Hz) or if the alignments being wrong (mix-up or just not adequate as was already mentioned, what is very possible too) possible to check only running an accurate simulation with max. power used as in a real situation. The graph below is at it's peak ~800W/4Ohm for your verification of what is said.
This is the driver/speaker as is:
(1) PIONEER TS-W310, VB = 61 L@35 Hz, 88.1 dB/2.83V/m. (2) 54.04 V. or max. excursion.
The port is very long, already said for that kind of "bad behaved driver" and has a (port) nasty resonance at ~200Hz. Stuff the port a little (?!?)/a lot, good or not, test...
And please don't compare it with another driver that you don't know the specs of. As sreten said is very badly screwed already... (NPI)
(OP) All members (almost) already referred to you that a BR is really messy, can you explain the audience your insistence to make it work (after all this work, I guess so...!!!)
(Sometimes threads get very long and difficult to follow, as you must imagine...)
Anyway, as you see that's the most difficult driver (type/parameters, there are many like that) that you had to run against. Even his evil brothers S4, D4 are easier to manipulate.
And, as you see, again, that's not a practical length for a port, and it takes all the space inside the speaker. Before we can compare this driver/speaker with another we have to have a good implementation, what is not the case. Did you linked a simulation (made by you) for it already? Did you mention your amp already? Take care.
(Let's make another try, simulation in my computer...)
I'm not used to the specs of this driver but maybe someone can refer to it's stupidly high reference specs like Qts of 1.16 that his very high (and Qes, Qms). Obviously it works in a OB (notice the high Qms) or sealed, not the best in this class too with only like one type Q, not being flexible or responsive to the size of the enclosure.
You might run into other issues like the cone/coil running against the pole plate or getting out of the gap with max. excursion at lower freqs. if drived to hard (<25 Hz) or if the alignments being wrong (mix-up or just not adequate as was already mentioned, what is very possible too) possible to check only running an accurate simulation with max. power used as in a real situation. The graph below is at it's peak ~800W/4Ohm for your verification of what is said.
This is the driver/speaker as is:
(1) PIONEER TS-W310, VB = 61 L@35 Hz, 88.1 dB/2.83V/m. (2) 54.04 V. or max. excursion.
The port is very long, already said for that kind of "bad behaved driver" and has a (port) nasty resonance at ~200Hz. Stuff the port a little (?!?)/a lot, good or not, test...
And please don't compare it with another driver that you don't know the specs of. As sreten said is very badly screwed already... (NPI)
(OP) All members (almost) already referred to you that a BR is really messy, can you explain the audience your insistence to make it work (after all this work, I guess so...!!!)
Attachments
![(1) [B]PIONEER TS-W310[B], VB = 61 L@35 Hz, 88.1 dB2.83Vm..jpg](/community/data/attachments/344/344523-520dc93cdea800278fedc3d91d7c9467.jpg)
Just a theory.
It is possible that he's having an issue with "phase cancellation"; backwave nearing 180 deg "out of phase" at the "port opening". To eliminate the possibility of that being the cause, just (temporarily) block-off the port (stuff it with a pillow) completely. If the level increases, mystery solved; Just curious.
rigtec, cheers
It is possible that he's having an issue with "phase cancellation"; backwave nearing 180 deg "out of phase" at the "port opening". To eliminate the possibility of that being the cause, just (temporarily) block-off the port (stuff it with a pillow) completely. If the level increases, mystery solved; Just curious.
rigtec, cheers
Yeah I am still pretty new to building enclosures and so far ports have been the number one issue I face. I build vented for the bass extension and efficiency, so i tend to tune the boxes i build from 30-35, and i always get very long ports in order to keep around 12-15in^2 per cubic foot of volume as the port area.
It seems like the problem is with the sharp turns because my box has none of the angles. :/
(OP) Thanks for the info.
(Sometimes threads get very long and difficult to follow, as you must imagine...)
Anyway, as you see that's the most difficult driver (type/parameters, there are many like that) that you had to run against. Even his evil brothers S4, D4 are easier to manipulate.
And, as you see, again, that's not a practical length for a port, and it takes all the space inside the speaker. Before we can compare this driver/speaker with another we have to have a good implementation, what is not the case. Did you linked a simulation (made by you) for it already? Did you mention your amp already? Take care.
(Let's make another try, simulation in my computer...)
I'm not used to the specs of this driver but maybe someone can refer to it's stupidly high reference specs like Qts of 1.16 that his very high (and Qes, Qms). Obviously it works in a OB (notice the high Qms) or sealed, not the best in this class too with only like one type Q, not being flexible or responsive to the size of the enclosure.
You might run into other issues like the cone/coil running against the pole plate or getting out of the gap with max. excursion at lower freqs. if drived to hard (<25 Hz) or if the alignments being wrong (mix-up or just not adequate as was already mentioned, what is very possible too) possible to check only running an accurate simulation with max. power used as in a real situation. The graph below is at it's peak ~800W/4Ohm for your verification of what is said.
This is the driver/speaker as is:
(1) PIONEER TS-W310, VB = 61 L@35 Hz, 88.1 dB/2.83V/m. (2) 54.04 V. or max. excursion.
The port is very long, already said for that kind of "bad behaved driver" and has a (port) nasty resonance at ~200Hz. Stuff the port a little (?!?)/a lot, good or not, test...
And please don't compare it with another driver that you don't know the specs of. As sreten said is very badly screwed already... (NPI)
(OP) All members (almost) already referred to you that a BR is really messy, can you explain the audience your insistence to make it work (after all this work, I guess so...!!!)
For the port, how would i be able to get a tuning of 30hz without having such a long depth? Keeping in mind that the turbulence and velocity should be kept down to a minimum.
And i think in post 8 I posted all the simulations that WinISD gave me (I dont have any other program or simulator that i know of D
And yeah the amp is an XTi1000 in bridged mode
As for the port resonance i thought as long as it is above the LPF cutoff, It shouldn't prove to be a problem, I just ran some tests with polyfill stuffing in the vent. With a little and a lot the SPL ran from 80 to 78 on both tests, so it takes away from the spl and doesn't help very much with the port noise.
If you mean what this subwoofer is designed for, then its for my friends car (GTi). (Im sorry but i dont think i fully understood the last question)
As for this test i ran a sine wave at 80dB, put the pillow in the vent and the SPL ran down by 2dB. This happened at 30, 35, 40, and 50hz
So im guessing that i'm not getting any phase cancellation due to the port
I'd expect a greater reduction in SPL at those frequencies if the Fb of the box is actually around 35 Hz. Are you able to confirm Fb by measurement?
Yeah I am still pretty new to building enclosures and so far ports have been the number one issue I face. I build vented for the bass extension and efficiency, so i tend to tune the boxes i build from 30-35, and i always get very long ports in order to keep around 12-15in^2 per cubic foot of volume as the port area.
It seems like the problem is with the sharp turns because my box has none of the angles. :/
For the port, how would i be able to get a tuning of 30hz without having such a long depth? Keeping in mind that the turbulence and velocity should be kept down to a minimum.
And i think in post 8 I posted all the simulations that WinISD gave me (I dont have any other program or simulator that i know of D
And yeah the amp is an XTi1000 in bridged mode
As for the port resonance i thought as long as it is above the LPF cutoff, It shouldn't prove to be a problem, I just ran some tests with polyfill stuffing in the vent. With a little and a lot the SPL ran from 80 to 78 on both tests, so it takes away from the spl and doesn't help very much with the port noise.
If you mean what this subwoofer is designed for, then its for my friends car (GTi). (Im sorry but i dont think i fully understood the last question)
As for this test i ran a sine wave at 80dB, put the pillow in the vent and the SPL ran down by 2dB. This happened at 30, 35, 40, and 50hz
So im guessing that i'm not getting any phase cancellation due to the port
You port is really excessively large. I would cut the port area by about 50% and reduce the length as needed, aim for a port airspeed peak of around 25-30 m/s at max output. Put in 45's as needed and round over all sharp edges!
Maybe it's just me. The trouble you were having was with the "Maximum SPL" of being only 105db. Is there any reason that you performed the "phase cancellation" test @ just 80db? I'm not stating that I'm sure it would make a difference, but a 25db power reduction is huge. Just sayin'...
Regards
Yeah, I did the test where you put a coin or something on the cone and when the object is basically not moving its at the Fb. And that frequency was at 35hz.
I had read about this alot and some people say 17m/s peak, some say 30m/s. Is there a way to test to actual velocity coming out of the port or is it something that you have to go by using simulators?
Designing ports seem to be the number one pain in the *** when designing these boxes :l
I performed it at 80db because it seemed like a good base point. I have just tried to redo the test, and I ended up popping the speaker at 86dB @35hz....
To come back to your original question: it is a crappy driver, for sure. Such a high Qts spells trouble. It implies a weak motor = low efficiency + the need to build huge enclosures that will not measure straight.
On top of it, specsheet just gives Qts, not split up in mechanical and electrical. In other words, it might have a low Qms, even further pushing the efficiency down.
Next time, try to find a subwoofer with a Qts of around .37 and a high Qms (5 is good but higher is better).
Yeah what im going to probably do is open up this box and reuse all the wood to make a better designed ported box (I was thinking about buying an alpine type E 12 inch) but i still have to look around for more drivers
btw, the Qms is 9.18 with a Qes of 1.33
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I'm sure it can be measured some how, but I'm talking about similated max velocity. Playing music at full output, with a 30 m/s port velocity, everything else will be more than loud enough to mask any normal port chuffing.
Port Flares - Evaluation of noise
Oh alright, rebuild a new box with a different driver using that as my port guideline and ill post it up once its finished with the results
thanks for the link
Ahh! So there was really was something "seriously wrong"" with that Driver all the while. Now you know! Time to choose a quality replacement!
rig, cheers
The edge on panel brace is good. BUT it must be very securely attached.
If and when the panel tries to flex the stress on the joint is very high.
Glue alone may well not be enough.
The plywood may shed a layer, when trying to remain attached.
The side to side brace is good. Very good in compression (it won't need any glue). Absolutely useless in tension.
You MUST secure the side to side brace to support both compression load and TENSION load. Otherwise it is useless.
The panel supporting the driver could do with some help.
You should try to stop the panel "panting" when the driver chassis reacts against the cone moving.
BTW,
screws into end grain do not hold well.
Use very long screws (60mm to 100mm long) with a coarse thread into a pre-drilled hole to prevent splitting.
Screws into the side of softwood grip very well. 20mm to 40mm of engagement is good enough.
If and when the panel tries to flex the stress on the joint is very high.
Glue alone may well not be enough.
The plywood may shed a layer, when trying to remain attached.
The side to side brace is good. Very good in compression (it won't need any glue). Absolutely useless in tension.
You MUST secure the side to side brace to support both compression load and TENSION load. Otherwise it is useless.
The panel supporting the driver could do with some help.
You should try to stop the panel "panting" when the driver chassis reacts against the cone moving.
BTW,
screws into end grain do not hold well.
Use very long screws (60mm to 100mm long) with a coarse thread into a pre-drilled hole to prevent splitting.
Screws into the side of softwood grip very well. 20mm to 40mm of engagement is good enough.
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I added some more wood .Here is picture
And I heard that driver side should be thicker right? Should I add and paste one more sheet on the bottom (it will be downfiring sub )
And what spikes do you recommend? I think it will be around 25kg total.Is it not light for a 12 inch sealed subwoofer ?
And i Will use linkwitz correction.I am not sure I need 20hz.Maybe i will make it 30hz cutoff
A lot of work.It is hot here
Thanks
And I heard that driver side should be thicker right? Should I add and paste one more sheet on the bottom (it will be downfiring sub )
And what spikes do you recommend? I think it will be around 25kg total.Is it not light for a 12 inch sealed subwoofer ?
And i Will use linkwitz correction.I am not sure I need 20hz.Maybe i will make it 30hz cutoff
A lot of work.It is hot here
Thanks
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