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Discussion Starter · #1 ·
I'm going to be putting together a modest little sub to augment the bookshelf sized speakers I'm making for my parents HT. I've modelled lots of entry level 8" and 10" subs and have it narrowed down to the Dayton DCS205 or DCS255. Space limitations are <1cuft. Price-wise the 70W plate amp makes the most sense, the next best deal is the 240W but that power isn't easily used in such a small box and other limitations like no room for a huge port. Amp + driver should be ~$150-200. Both of these look good and are in the lower price range.

the 10" in blue and the 8" in green, both xmax limited (extra filter on the 8") and on 70W, both vented in ~.9cuft. Which looks better? The 8" is flatter but the 10 has waaaay more 20Hz output. This is a big consideration since this will be in a big open room. All the sub needs to do is fill in some stuff in the sub 100Hz range, and will rarely ever be played very loud.

 

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the vent air velocity is way to high. For a 2" vent stay below 10m/s or it will choke. I'd put the 10" in a 1' sealed box and use 70w.
 

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Discussion Starter · #3 ·
Sealed in that space the $60 cheaper DCS205-4 does as well as the RSS210 does. So it's either the RSS210 vented, or the DCS205 sealed. Still undecided, cost might be the deciding factor.

The RSS210 with a little different tune would have a port velocity of 29m/s, but way down at 21Hz. Considering they say compression doesn't start until 17m/s and chuffing becomes audible at 27m/s I think it's still a build to consider. This isn't a sub that will be played near it's max volume very much.
 

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The RSS210 with a little different tune would have a port velocity of 29m/s, but way down at 21Hz. Considering they say compression doesn't start until 17m/s and chuffing becomes audible at 27m/s I think it's still a build to consider. This isn't a sub that will be played near it's max volume very much.
I'm curious, who is saying that a 2" (5cm) round port starts compressing at 17m/s?

Flow simulations (in SolidWorks) show core limit at 10m/s and exit boundary separation (chuffing) at 7m/s (with 1"rad. flare) . (I was checking that 'Flare-it' was accurate, it is.)

(all with 1" radius flare)
3.5" round vent shows a core limit of 17m/s, chuff at 7m/s
4" core limit 20m/s, chuff 8m/s
6" core limit 26m/s, chuff 12m/s
8" core limit 32m/s, chuff 15m/s
 

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Discussion Starter · #5 ·
Donno, I thought that was the general rule. Guess not?
 
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