Recommended sealed volume for Dayton RS315HF?

[silvercans]

I was messing around with some modeling software for my Dayton RS315HF and to my surprise it came back with a recommended sealed volume of 1.268 cf with some fill (F3 was 41 HZ). Does this sound right? From what I read on the forum it seems people are recommending much bigger volumes. What do you recommend? Thanks

[Dennis H]

Much bigger. Going back to SL's spreadsheet, box air-spring distortion is proportional to 1/box size.

(air spring distortion %) = 140 * (one way driver displacement) / (box volume)

Edit: that's my theory about why an IB sounds better than a sealed box. The air spring distortion is zero for the IB.

[silvercans]

Thanks for the response. Could you recommend any IB designs using two RS315HF's?

Anyone else? I'm still curious to know what you recommend for a sealed volume.

[silvercans]

no one? how about 2cf sealed?

[Dennis H]

To model an IB, just enter 10,000 liters as the box volume in your software sim for a sealed box.

[ThomasW]

Dennis,

He's confusing 'true' IB with acoustic suspension/ small sealed box.

[silvercans]

No I completely understand Dennis' recommendation for an IB. However, I may not go that route and needed to know what some would use if they had to choose sealed.

[jkrutke]

RSS315HF Sub Design

First post on this forum, I think. I just tried to post this on the PE forum and it puked on me.

I used 2.0 cu ft sealed. Sounds very good. I'm very happy with this sub.

[JonMarsh]

Nice looking design, John, and thanks for posting a link to an archive zip. easier than downloading the web page itself to my HD (my usual tactic!)

A lot of people who don't usually like subs will like subs done with these Dayton RS series drivers. My theory about that is that the integration with whatever main system you use is better because of the low VC inductance (which means they don't start rolling off around 70-80 Hz like so many super long throw drivers), and the extended response to 200 HZ and beyond, as well as very stiff, rigid cones. I like your sealed design, and it's similar (in volume and concept) to something I'm considering for the bottom end of a floor standing speaker (a large floor standing speaker!).

Still more points to ponder, as it's intended for music mostly, I might go ported (tuned low with tapering response) or might go sealed for the reasons you give.

Happy New Year, and hope you drop by HT Guide from time to time.

~Jon

[KeithM]

no one? how about 2cf sealed?

With WinISD I'm it looks like 2 cubic feet would be good with an F3 around 46.5 hz.

[silvercans]

That's interesting because the software I was using said a 2cf would yeild a F3 of ~40hz.

[Paul W]

John,
Nice looking sub! Is the baffle paint or metal?

If you don't mind, would you send me the impedance file for that driver? Free air prefered but box okay. pnwright3@yahoo.com
Happy new year!
Paul

[jkrutke]

The baffle is paint. It's Rustoleum Bright Coat Metallic Aluminum Finish #7715. When it's painted over two coats of textured enamel #7720, it looks exactly like an aluminum casting. Then for good measure I put a clear coat over that, and it's very durable. It's a great look that I'm going to start using more in the future. I think I like it more than any kind of wood, and it's much easier to do.

I don't actually have an impedance file. I got the T/S numbers a while back and they were dead nuts identical to the numbers posted at PE, even the Vas. No worries using PE's numbers. My impedance curve posted in the design is generated from the T/S numbers.

[jkrutke]

A lot of people who don't usually like subs will like subs done with these Dayton RS series drivers. My theory about that is that the integration with whatever main system you use is better because of the low VC inductance (which means they don't start rolling off around 70-80 Hz like so many super long throw drivers), and the extended response to 200 HZ and beyond, as well as very stiff, rigid cones. I like your sealed design, and it's similar (in volume and concept) to something I'm considering for the bottom end of a floor standing speaker (a large floor standing speaker!).

You make good points about the VC inductance. I also noted that this driver has less of a nasty peak/dip in it's upper response. (I did a quick full range impulse through the amp with the LFE input) It's not nearly as bad as a Peerless XLS. I've only done distortion tests on a few subs in my life, but this Dayton was overall cleaner than anything else to come through my house.

If I ever needed more output, I'd simply buy two of these rather than one of the "super-subs" out there.

My setup was for HT only. For music only, I would guess that vented would be acceptable too. Less chance of a stray 15hz coming through and bottoming the sub out. :B

[Paul W]

John,
Couldn't tell if it was paint or metal & thought my eyes were not good enough! Interesting finish...I'll try it sometime.

I'm not so interested in T/S parameters as glitches & wiggles in the impedance curve to get an idea of how high it can go before the nastys set in. I'll take anything ya got in that area!
Paul