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home theater driver for 3-4ft3 enclosure?

6K views 55 replies 4 participants last post by  tys 
#1 ·
Looking at the css sdx 15" but what do you recommend? i am looking at the dayton 1000 watt amp. preferrably a 15"?
 
#2 ·
Welcome to the Shack Ty,

Here is what I would do with the SDX 15 as per your requirements.
 

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#4 ·
I don't know the tech 15 tl+ sub, but just let's know what you desire... What's your room volume? How much of improvement youn want compared to a single 15" ported sub.

Take note that 4 cuft for the SDX 15 will only allow to have a sealed configuration, which has less output at low frequency compared to the same driver in a larger ported enclosure...
 
#7 ·
i have decided to do the 4 ft3 with that driver. i was wondering though if i should eq it on the lower end
I would boost a little bit at 20 Hz to make bass deeper and softer, but yet that depends on actual FR once you have it in your room.
would i need a subsonic filter?
No. A sealed configuration will act as a damper at lower frequencies to prevent the woofer from over excursion....as far as you stick with 4 ft3 and 1000 W RMS (theoretically).
 
#8 ·
the other driver i was looking at was the mach 5 ixl15 ported. which do you think would be the better choice?
With 4 cuft volume, you don't want to have any of those subs ported for HT, the enclosure would be too small to insert a port.
Below is a comparison between the drivers you mentioned. The SDX 15 is in blue, and I prefer that driver over the Mach 5.
thank you for all the help. i love this site.
It's my pleasure :)
 

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#9 ·
I appreciate all of your time. i have one last question:
Theoretically if you went with a smaller enclosure such as a 3 ft3, you could compensate the lower end by eq'ing? If this is not the case how do the small box systems do it like velodyne and sunfire? If that were the case would I build the 3.4 ft3 enclosure on the css website and eq more on the low end?
Thank you
 
#10 ·
Hey Ty,

Ask as many questions as required till you feel completely comfortable...
You could but the sub would be less efficient at the lower octaves and therefore would need more power from the amp. to deliver the same SPL. And theoretically speaking you gain about 2 db "for free" (well you pay for some more wood) at 20 Hz when proceeding with a 4 cuft enclosure compared to 3 cuft (using 1000 W).
See graph (red is 3 cu ft, yellow is 4).

Even Velodyne or others cannot outwin the laws of physics. They use equalization to boost the lower end, but again nothing is free, that is the price to pay for smaller enclosures.

I believe SDX-15 in a 4 cuft enclosure coupled with 1 KW amp makes a good marriage.
 

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#13 ·
I think it may be a benefit to add a BFD (but build the sub first and see). With a BFD you can have whatever Frequency response you want :) of course at the expense of headroom (nothing is free).

Why are you assuming the EP2500 is not enough? It can produce about 2000 Watts, it could power 2 of these subs.
 
#14 ·
He might be able to get the ports in there with the right box geometry
with 4 cuft and 6" port, that's about 110 cm long port :raped: It would have to go out of the box.
or a Polk Powerport design.
Do you know of any software to use for such a design?
The added low end extension might be worth the effort. If the OP can spare $200 for some passives then ?????
That is IMO the best alternative if the performance of a ported sub is definitely required.
But this will be worth the effort specially if the OP has a huge room to fill with bass.

Ty,

What's the volume of your room?
 
#15 ·
i will measure the room to be exact but it is larger with vaulted ceilings. The question about the amp was about the ep1500 not the 2500 not being enough.
A passive might be worth looking at.
also how does the sdx compare with the tc2000?
 
#16 ·
Apologies Ty, I think the EP1500 can produce more than 1000 W which is enough for 1 sub (I'll check).
 
#20 ·
The TC 2000 is not available anymore, and they are quite similar.
 
#22 ·
What are the T/S parameters of the TC9?
 
#23 ·
2 * 15" per sub
 
#26 ·
Xmax?
 
#28 ·
The vented SDX models better than the TC-9 , nevertheless you won't be able to properly insert 6" port that needs to be 110 cm (43 in ) long with 4 cu ft.
If you really need the performance of a ported sub, you must go PRs
 
#30 ·
Vented. The vented TC9 is better than the sealed SDX at 20 Hz by 5 db. But why compare to the sealed SDX? If you put the SDX in the same vented box, it performs slightly better. But the tune depends on the box itself, and it won't be easy to install the port whatever the driver.

So the SDX is better. The SDX 15 is a very good driver, I wouldn't give it up... If you can have a bigger box something like 10 cu ft, you'll be getting the very best out of it.
 
#31 ·
wife factor will not allow. the tc9 is stated to do well in a 4.1 ft3 enclosure ported. i did not think that the sdx would go ported in that size enclosure. That is why i was comparing the sealed. i am sorry i should have stated the 4 ft3 enclosure size earlier.
 
#32 ·
Ty,

You mention 4 cu ft earlier I think :). The problem is not related to the SDX or TC9, but the box itself. Tuning depends uniquely on the box volume and port length.
What I mean is if a box works for the TC-9, it will also work for the SDX.

I'll make some model comparison to show you what I mean.
 
#33 · (Edited)
Here is a representation of both subs theoretical behavior in exactly the same box. I still prefer the SDX despite the FR is not the best. But SPL capability and more importantly less expectable port noise and compression are in favor of the SDX, although it would have been a lot better with a bigger box and lower tune. I wouldn't worry a lot about FR since I have a BFD.
The only problem is now to physically insert a 6" port, 106 cm (42") long port in such a relatively small a box!
If you don't mind having the port get out of the box that would work (but not very esthetical). You could also use an internal elbow, or simply forget about that and procure yourself passive radiators.

Very Important:: Do you know a port this size makes about 0.71 cu ft , add 1.5 cu ft for the driver and bracing displacement... This means that this 4.1 cu ft internal volume sub you mentioned will be around 6 cu ft external volume!! (I'm not sure you expected that)
If you still need to stick with an easy and small build, you need to abide by the very first design I suggested according to your requiremenets (I saw all this coming :)).
You might want 2 of those whatever your decision ...

You chose!
 

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