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Subwoofer ideas for my future theater

Nice to know that I won't need to make any changes. For this application would I be using a pro audio amplifier? Like a QSC or Crown?

Any recommendations as far as the woofers go? I have been looking around on Parts Express, but am a little unsure of what to look for in this type of application.

Thanks so much for all of the information guys.
 
If my memory serves, Flint's IB sub drivers are Daytona Audio's 15" Titanic with QSC amp.
 
I prefer subwoofer drivers with:
- low Fs (around 20Hz is best)
- a Qts ranging between 0.30 and 0.40
- a high excursion (Xmax), reasonable power handling (you can only get about half the rated power handling when in an IB setup)

I recommend calculating the acoustic power output of each woofer you are investigating at half the rated power to see which will generate the most output per dollar spent.

I did the calculation on output per dollar and found the Selenium 18SWS800, RCF LF21N451, and EV EVX-180B are among the best choices from the Parts Express catalog of speakers. Two of any of those with a good, clean amp would rock your house - you would also need an EQ to flatten out the bottom end of the response. If you can tell me the approximate volume of your HT I can calculate the estimated peak SPL in your room at 20Hz for any of those woofers.


For amps, I like pro amps best, but look for one with a defeatable subsonic filter. I use a QSC RMX2450. It can power up to four of the Titanic MkII 15" woofers I chose, but I only use two since my room volume is small.
 
Wow, thanks! The volume of the room is roughly 4000 cu ft. 16W x 25L x 10H are the dimensions.
 
2ea EV EVX-180B approximately 107dB SPL at 20Hz with 1,000 watts total power (500W at 8 ohms x2)
2ea Selenium 18SWS800 approx. 103dB SPL at 20Hz with 800 watts total power (400W at 8 ohms x2)
2ea RCF LF21N451 approximately 109dB SPL at 20Hz with 1,500 watts total power (750W at 8 ohms x2)

You'll have to build a manifold, but the RCF is the best deal at $500 each.
 
If you add two more woofers you can increase the output level by about 6dB SPL.
 
Thanks for doing so much leg work for me. Looks like a pair of the RCF woofers is in my future.

Next thing to research is best type of manifold design.
 
From what I gather a transmission line will give you the best result. It looks to me like the simplest installation too.

I'm kind of researching this stuff right along with you really...
 
Transmission line subwoofers are quite impractical as the pipe lengths tend to be too long for practical use and the stuffing is hard to predict and extreme impactful. I don't recommend DIY transmission line subs.

All the benefits of TL performance are bettered by IB performance. In fact, the most ideal subwoofer loading will always be IB since all enclosure issues are resolved with them.
 
Keep in mind that is a 21" sub, so it probably will not fit between your studs. You will like have to make a manifold for them.
 
Do you see any negatives to using such a large woofer? I know that may be a dumb question, but it doesn't seem like you see people using 21" woofers often.
 
lakedmb said:
Do you see any negatives to using such a large woofer? I know that may be a dumb question, but it doesn't seem like you see people using 21" woofers often.
Click to expand...

In this case, the positives outweigh the negatives.

Nagatives:
Large and heavy
Require a manifold or some other mounting option

Positives:
Moves much more air per mm of motion
Fewer drivers required
Simpler powering and wiring options
Higher output
best bang for the buck
 
Ok, that makes me feel better.


Next quesion, I noticed that the EV (20hz) had a lower frequency response than the RCF (30hz). Is this going to make any real world difference?
 
Sorry, I missed your last post somehow Flint. Nice to know about the woofers, thanks!

Out of curiosity, does a 31-Band EQ work similarly to the parametric EQ you recommended?
 
lakedmb said:
Out of curiosity, does a 31-Band EQ work similarly to the parametric EQ you recommended?
Click to expand...
Similar but not really when it comes to details. 31-band is graphic eq which has fixed Q (width of controlling frequency) whereas parametric eq has variable Q, meaning that you can widen or narrow the controlling frequency range. Some PEQ has variable frequency setting as well (can control multiple areas within one octave). Also, PEQ allows more precise control but tricky to use and requires some practice. You can still use 31-band eq for your need but may not be as effective as PEQ for eq-ing bass.
 
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