Which Dayton RS sub?

[ChaoticKinesis]

I'm looking to build a sub using one of the Dayton RS subwoofers. I plan to put it in a sealed box of roughly 3 cu. ft. Having modeled the options in unibox I see that the 15" HF would give me what is probably a higher than desirable Qtc. The 15" HO gives a much better Qtc and the 12" HF also has a nice Qtc.

So my question is are the SQ benefits to be gained by going with the high fidelity models significant enough to downsize to a 12"? Is the slightly highish Qtc of the 15" HF not a problem? Or is the difference not that great and I should go with the 15" HO?

These will be used nearfield in a roughly 12' x 20' room which opens up to a narrow hallway.

[Inu_Yasha]

I would say go with the 15" as you'll be able to play lower and louder. I doubt that there's anything to be gained by going with a 12" (if you're referring about quickness, many agree that that is a myth).

[ChaoticKinesis]

I did not think there was much to be gained by going with a 12," it's primarily a matter of high fidelity woofer with higher Qtc vs. high output with lower Qtc. The only reason I asked about the 12" is if the sound quality of a high fidelity is enough of an improvement to be worth downsizing, to which I figure the answer will be an emphatic no. I'll attach my simulation graphs. The respective Qtc's are: .731 for RSS390HF, .546 for RSS390HO, .586 for RSS315HF.

In the sims they are getting 230 watts because I intend to power them with a Behringer A500, which I may choose to upgrade at a later point.

[ChaoticKinesis]

So I would still like to know which is better for a sealed 3 ft^3 box:

1. 15" HF with a Qtc of .731 or
2. 15" HO with a Qtc of .546.

[gitarretyp]

So I would still like to know which is better for a sealed 3 ft^3 box:

1. 15" HF with a Qtc of .731 or
2. 15" HO with a Qtc of .546.

I'm curious about the answer as well, but i'm getting a Qtc of .853 and .607 respectively for those in WinISD.

[ThomasW]

0.546 is nice

[ChaoticKinesis]

I'm curious about the answer as well, but i'm getting a Qtc of .853 and .607 respectively for those in WinISD.

I'm modeling them using heavy fill and minor leaks.

[ChaoticKinesis]

0.546 is nice

Thanks Thomas, that was what I thought. :T

[PMazz]

I'm curious about the answer as well, but i'm getting a Qtc of .853 and .607 respectively for those in WinISD.

Stuffing will increase the Vb. Try using ~4ft^3 Vb in the sim.

The higher inductance of the HO will probably affect the response and it'll behave more like the HF, albeit with higher power handling.

Pete

[ChaoticKinesis]

Whoops, didn't notice he was using WinISD rather than UniBox.

Stuffing will increase the Vb. Try using ~4ft^3 Vb in the sim.

The higher inductance of the HO will probably affect the response and it'll behave more like the HF, albeit with higher power handling.

Pete

What do you mean when you say the higher inductance will make it behave more like the HF? Isn't the higher inductance just going to make the high frequency rolloff occur at a lower frequency?

[elfranche]

I would say go with the 15" as you'll be able to play lower and louder. I doubt that there's anything to be gained by going with a 12" (if you're referring about quickness, many agree that that is a myth).

hmm.. granted, most 15s are more efficient, but Ive seen quite a few 12"s which played lower than 15"s, in fact I'd say the champions of F3 are almost always 12"s... furthermore, the NHT1259 would outperform them all in a sealed 3cuft.

[PMazz]

What do you mean when you say the higher inductance will make it behave more like the HF? Isn't the higher inductance just going to make the high frequency rolloff occur at a lower frequency?

I should have said it'll behave more like it in that sized box. So, instead of the nice smooth FR you'll wind up with something that looks like it has a higher Q.

Pete

[Dennis H]

Qa is how you adjust for stuffing. Looks like he's already got it set for heavy stuffing with Qa = 5.