PE RS series Sub

[alexh]

Thomas, how does this sub look , for a small IB? ???The specs look good from everything I have read. But would like your honest opinion. Thanks

www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-464

[ThomasW]

They're very good drivers. Probably the pick of the liter for a great low distortion 12". Xmax is a bit limited compared to the Oaudio 12" TC2+.

The only issue using 12"s is that one needs a bunch of them to get adequate output. So think 4 driver minimium for any moderate sized room, as a result 15"s are more cost efficient.

[poppabirdy]

I'm in the planning stages for an IB. This forum has been inspiring! I will be building the IB in December.

I've read much of this forum but still don't feel I understand enough regarding the various speaker specs/parameters to make an informed purchasing decision. What makes a really good subwoofer for IB purposes? Here is what I have gleaned so far:

- the longer the xmax the better
- a lower FS will result in a lower hz from the IB
- bigger subwoofers can generally produce more volume for the buck
- the more subwoofers in the IB the lower the distortion

I've studied Formica's comparison chart and do not understand QTS and Efficiency. Would someone be kind enough to help me understand the speaker parameters that are important for IB?

Finally, I like what I read about the Dayton RSS315hf-4 speaker. This is not listed in Formica's comparison chart. Instead I see a High Output version that has a higher power handling capability. For an IB, which speaker is better?

Thanks for the help.

[ThomasW]

The only reason for using 12"s is if you're trying to fit a manifold between narrow floor joists

There's certainly nothing wrong the new Dayton drivers. However their Xmax is low for our needs/wants.

If you must use a 12" driver, use the TC2+ from www.Oaudio.com

There's no benefit to buying 6 or 8 -12"s, if you have room for 4-15"s.

T/S parameters

Sorry I don't do schooling on raw loudspeaker design, there's tons of info about that on the net

Overdamped = low Qts, underdamped = high Qts

Each has a distinctive sound, most people seem to prefer a "Q" around 0.4-0.6 That's not etched in stone though...

What's called a 'critically damped' small sealed box has a Qtc of 0.5

For an IB sub the driver's Qts = the system's Qtc.

[ryans]

Efficiency is generally not a concern for IB subs. Using a very large box and multiple woofers gives you a big advantage in sensitivity.