TC SOUNDS EPIC 8" sub

[donradick]

Hi all -

I got a pair of these a couple of months ago when they were DOTD.
tc-sounds-epic-8-dvc-subwoofer--293-657

I planned to build a smallish sub for my study or bedroom - maybe 90-95 dB tops.

Here's the params:

THIELE-SMALL PARAMETERS
Resonant Frequency (Fs) 24 HzDC
Resistance (Re) 3.72 ohms
Voice Coil Inductance (Le) 2.31 mH
Mechanical Q (Qms) 7.2
Electromagnetic Q (Qes) 0.26
Total Q (Qts) 0.25
Compliance Equivalent Volume (Vas) 0.57 ft.³
Mechanical Compliance of Suspension (Cms) 0.32 mm/N
BL Product (BL) 15.2 Tm
Diaphragm Mass Inc. Airload (Mms) 108g
Maximum Linear Excursion (Xmax) 18.1 mm

I'm thinking about a PR box, about 1 cf tuned to 31 Hz. Doesn't look like Xmax is exceeded with 300W.

Does that sound reasonable? Any feasible alternatives?
How would this PE 12 inch PR work for this design? sd315-pr-12-passive-radiator--295-496


Thanks in advance.

[[email protected]]

Re: TC SOUNDS EPIC 8" sub

You might want to run it through Deffraction and Boundry simulator to how much room gain you will get.

[aarond]

Re: TC SOUNDS EPIC 8" sub

Win ISD will tell you whether or not the Dayton PR will do what you need it to. I haven't run the sim but I'd be surprised if it has enough Xmax.

[Jay1]

Re: TC SOUNDS EPIC 8" sub

The PR with 200g mass added will tune you to 30hz in 1 ft3. You will 100% need a 30hz hpf like included on the Yung plate amps (or a pro amp). With the 30hz filter PR xmax is reached with 200 watts, but exceeding this will only compress the output at tune (30hz). Without a filter there is also a peak of 3 db at tune, which flattens with the filter.

[aarond]

Re: TC SOUNDS EPIC 8" sub

The PR with 200g mass added will tune you to 30hz in 1 ft3. You will 100% need a 30hz hpf like included on the Yung plate amps (or a pro amp). With the 30hz filter PR xmax is reached with 200 watts, but exceeding this will only compress the output at tune (30hz). Without a filter there is also a peak of 3 db at tune, which flattens with the filter.

For headroom purposes I'd recommend a pair of the 12" PR's (if they can handle the 14+ ounces of weight). Or you might be able to get away with a pair of 10" PR's which would require less weight but would also provide less Xmax.

This is exactly the problem I run into with high Xmax subs in small low tuned enclosures. A PR is practically a necessity but the Dayton SD series doesn't have the Xmax to get the job done. Stepping up in size or in multiples then requires (possibly) impractical amounts of weight.

The SD series has been around for a while and seems more compatible with "woofers" (not subs) in larger enclosures. Meanwhile thousands of cones and suspensions of RSS series of subs sit on a shelf in China feeling underutilized. ...and I sit around scratching my head for years trying to figure out where to get ballzy smaller diameter PR's for these mighty mouse subs.

#firstworldproblems

[thekorvers]

Re: TC SOUNDS EPIC 8" sub

This would not be my first choice in a HT setup. It is more suited for a tiny enclosure (+ 0.4-0.5 cu ft) with a PR. It would work well in a car. I would not mount this driver in an enclosure of 1 cu ft, unless accompanied by a stout (read "expensive") PR with lots of xmax.

That said:

In a box of 0.4 cu ft with one of the 12" Dayton PR's mentioned with 400 g of added mass, it will handle 200 W before the PR peaks at it's 10 mm xmax at + 33 Hz. The driver does not even come close to it's rated xmax at this point. Both driver and PR will exceed their respective xmax at + 14-16 Hz without a filter. f3 is 33 Hz with this alignment and max SPL 104-105 dB at 200 W. Not great, but very nice for such a small enclosure if that is what you are looking for. As always there are trade-offs: This driver is very inefficient and requires lots of power for decent output.

[donradick]

Re: TC SOUNDS EPIC 8" sub

Thanks for the input guys -

Well, I found the Unibox sheet with PR excursion limits. :eek:

This alignment is looking pretty good (thanks thekorvers). Is 400 g added mass reasonable?
In a box of 0.4 cu ft with one of the 12" Dayton PR's mentioned with 400 g of added mass, it will handle 200 W before the PR peaks at it's 10 mm xmax at + 33 Hz. The driver does not even come close to it's rated xmax at this point. Both driver and PR will exceed their respective xmax at + 14-16 Hz without a filter. f3 is 33 Hz with this alignment and max SPL 104-105 dB at 200 W. Not great, but very nice for such a small enclosure if that is what you are looking for.

for my application, the easiest thing to give up is max SPL, and 100 dB should be more than enough.
With boundary gain (on the floor of course, probably next to a wall) I should have plenty of output.
Outside of some Yello tracks, I don't forsee any music with significant < 40 Hz content.

So, the next question - plate amp?

Dayton 100 or alternative? Looks like the Yungs all have a boost which I don't need. Maybe an ApexJr amp?

[thekorvers]

Re: TC SOUNDS EPIC 8&quot; sub

Unfortunately Dayton does not have a spec for the max amount of added mass for their PR's. I seem to recall Wolf stating a max amount of 250 g for the 8" version, but am not sure of this. If that is so, I think 400 g for the 12" version should be OK. If it was indeed Wolf who mentioned this in one of his posts, I don't know where he got this information. Maybe he can weigh in on this.

As far as the plate amp is concerned, the Yung amps do come in unboosted versions as well as boosted and one of those would be exactly what I would use, since their cost is very reasonable and they have a good reputation.

You indeed would want the unboosted version as the low end output actually rises around 40 Hz in this alignment which may cause some boominess depending on your room. I would prefer to roll off the response at that point instead of rise and have room gain take over. However this is hard to do in this alignment as it would require much larger amounts of added mass and I don't think this particular PR will be able to handle it. The rise is only + 1.5 dB and a good receiver with room equalization should be able to take care of any boominess if present. As always the alignment is a set of compromises, but seems like a decent solution at reasonable cost.

I personally would shy away from the 100 W version Yung amp in this case, because I think it is good to have adequate headroom. I would go for the 200W version or even the 300 W version as the additional cost is marginal.

[thekorvers]

Re: TC SOUNDS EPIC 8&quot; sub

[Pete Basel]

Re: TC SOUNDS EPIC 8&quot; sub

That is one impressive looking driver. You might want to tune a bit lower, say 28 to
get a bit more extension.
They used the PE passive radiator here and I think that they were able to overload it:

http://techtalk.parts-express.com/showthread.php?234058-Digger8-Sub-diggity-dig-it-all-the-way-to-20Hz&highlight=infinity+woofer

[donradick]

Re: TC SOUNDS EPIC 8&quot; sub

That is one impressive looking driver. You might want to tune a bit lower, say 28 to
get a bit more extension.
They used the PE passive radiator here and I think that they were able to overload it:
http://techtalk.parts-express.com/sh...nfinity+woofer

Thanks Pete! - I may yet give up on the TC 8 - it's a total beast, but my needs could easily be served with the Digger8

[Jay1]

Re: TC SOUNDS EPIC 8&quot; sub

You could do something like a 10" x 14" x 14" box with a .75" x 8.5" slot port that wraps the entire interior (34" long) for a .5 ft3 30hz tune that will keep air velocity to 30 ms with 300 watts. Given the way long slot ports like this are calculated you will likely be tuned closer to 28hz then 30.

[Pete Basel]

Re: TC SOUNDS EPIC 8&quot; sub

I only meant to give you some ideas from that thread.
Why not build something similar with your driver, I think you'll need even
more PR output since the TC-8 has more Xmax.

[Wolf]

Re: TC SOUNDS EPIC 8&quot; sub

Unfortunately Dayton does not have a spec for the max amount of added mass for their PR's. I seem to recall Wolf stating a max amount of 250 g for the 8" version, but am not sure of this. If that is so, I think 400 g for the 12" version should be OK. If it was indeed Wolf who mentioned this in one of his posts, I don't know where he got this information. Maybe he can weigh in on this.

It used to be in the spec-sheet for all of the SD series PR's. I don't recall if it's in an old catalog or not, but I know they all had limits. I have an old spec sheet for the SD215 somewhere, and it listed a max mass capacity. I would not think 400g would be out of line on the 12" SD PR, but I do not recall what those limits were.

Later,
Wolf

[donradick]

Re: TC SOUNDS EPIC 8&quot; sub

Thanks guys - all this discussion has given me confidence that my goals will be met.
Going forward with the TC 8 and the PE 12 PR. I'll update this with the modeled
Diffraction and Boundary Simulator modeled response.