Dayton DCS205-4 8" Classic box - can you double check my box?

[ontariomaximus]

Dayton Audio DCS205-4 8" Classic Sub

Got a pair of these and did a little modelling.

Came up with:

.70 ft3 tuned to 36hz with a 2" port 7.83" long

Anyone want to double check?

will be used as a .5 in a 2.5 way setup.

thanks in advance

[greywarden]

As in one of the DCS205-4s is the 2 and the one in this particular enclosure will be the .5 ?

[ontariomaximus]

different mid - something in the 5.25 or 6.5 size range.
maybe the HiVi F5

[greywarden]

What did you model it with?

[ontariomaximus]

I used WinISD

[Chris Roemer]

Looks fine to me, for music. Should go below 40Hz, and be able to take full power nearly down to 30, so HT duty shouldn't blow them apart either.
I'd recommend aiming the port away from listeners, with a generous round-over. 2-1/2" wouldn't hurt for an 8".

Chris

[mdocod]

Hello Ontariomaximum,

The box size is fine, the tuning frequency is fine.

2" diameter port is a compromise area. My suggestion if you must stick with this size to keep the length under control, is to pick up a flared port kit from PE, and DOWN or REAR fire it away from listeners to help dampen chuffing problems. A straight un-flared 2" port in this application would IMO, severely compromise the maximum usable and enjoyable output levels with chuffing caused by air velocities in excess of 40-50 meters/second possible. The flared port will cut the peak air velocity and port compression roughly in half (still too high IMO, but the down/rear facing should help cover up the remainder of the issue there).

Another trick, would be to take that flared port kit, and set it to the longest length your box will allow (keep skirt area from the port flange to nearest wall larger than port cross section at it's largest point), trying to move that tuning frequency down to ~30hz, which will move more of the chuffing problems down below more of the typical program material.

Best of luck with the project,
Eric

[ontariomaximus]

Maybe I should explore a t-line variant. About 6 feet long, area starts 1.25X radiating area to about .3X. That's just a guess. Or 8 feet long, 1.5X down to .8X. With little stuffing it would perform more like a cross between an infinite baffle and open back.

If I go vented, how about this idea: Make a .70 ft3 box except for a 1.5" x 7" wide slot at the back rear. Then add a rectangular port right on the back of the back with an internal dimension of 1.5" x 7" and 28" long. That tunes it to 36hz and also strengthens the box.

[mdocod]

Maybe I should explore a t-line variant. About 6 feet long, area starts 1.25X radiating area to about .3X. That's just a guess.

not bad at all.

Peak particle velocity at thermal limits or Xmax stops (whichever comes first):


4M/s, that's inaudible for all intents and purposes. Basically, no compression issues there.

----------------

Regarding the 8ft option proposed.... not as good. I'd pass.

Regards,
Eric

[ontariomaximus]

wow, I made a pretty damn good guess. 6 foot length it is then. Do I stuff this one or is it like a horn?

[mdocod]

The simulation is of an unstuffed tapered tube. I'd personally probably line the walls with some sort of acoustic dampening material. Yes, that would change the response from simulation, but probably not by enough to matter. I'd also suggest, that you download hornresp, and tinker with variations. You may find an alteration to that concept within a similar size that provides a more desirable response/extension/etc.

PS: yes, that was a pretty darn good guess