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Old 4th September 2007, 04:51 PM   #11
jcmjrt is offline jcmjrt  United States
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Quote:
Originally posted by planet10
A tough one... are the tannoys limited on the bottom because of their box? Or the driver?

dave
The Tannoy drivers could go lower if in a much larger box. If I went bass reflex, with about 9 ft3, I could get fairly low but I don't have a lot of space, and I like the quick, clean sound of the BLH. Bass reflex can be good but just not as good on the quick, clean scale thus the desire to augment the bass from another small source. The drivers are Tannoy Red 12"

http://www.44bx.com/tannoy/Tannoy_ts.html


Quote:
Originally posted by MJL21193


The amp would have to have plenty of headroom for transients. The Linkwitz transform circuit provides a proportional amount of boost below the tuning frequency of the enclosure. That could be as much as 20db gain.
The problem with Linkwitz transforms (LT) is that they are pretty much DIY - you need to calculate the proper values for many of the components. If you are not into electronic work, this can be daunting.
I picked the W5-1126SC because it has a huge Xmax for such a small driver. 2,3 or 4 could be installed in a small box (size you noted would be in the ballpark, maybe a little too big). This driver looks good for an LT.

At this point I need to correct myself (yet again). Compound loading will cut box size in half. In theory. you could calculate box size foe one driver and put two pairs, compound configuration. Thats four drivers in a box sized for one.
Obviously, I don't know much about LT and haven't done any real electronic design. I have tended to refurb (sometimes with very minor mods) good vintage gear with results to my liking...or built kits....but that's someone else designing.

I had rather figured that two drivers would probably be necessary to get the desired result and hadn't thought about four...that seems like a box full of drivers!...but I'm not averse if it would get me to the requirements.

Quote:
Originally posted by badman
Can you do us up a diagram, with how much space you have and where? A 4" driver (or multiples) represent a huge performance sacrifice. If we were able to get you up into 6.5" territory we could get you going with an Extremis or the like.
The major limiting factor is the height of the box...and 6 inches is really it. The speakers are under heavy, beautiful, built-in shelving in a corner which isn't going to move. I do realize that it's very limiting and hadn't seriously considered a colocated sub before until I saw the small drivers. I'm not looking to go very low so I was hoping that the small drivers could work.
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Old 4th September 2007, 09:47 PM   #12
Dr_EM is offline Dr_EM  United Kingdom
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I built a PMC TLE-1 style sub detailed in this thread:

PMC TLE1 style sub

It easily goes well under 40Hz so a smaller design with a limit closer to 40Hz could work.
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Old 4th September 2007, 09:49 PM   #13
poynton is offline poynton  United Kingdom
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Just for info :-

I saw this in the local Toshiba outlet

Small size subwoofer

[http://www.home-entertainment.toshib...0?opendocument]

So it can be done

Andy
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Old 4th September 2007, 09:57 PM   #14
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Quote:
Originally posted by poynton


So it can be done

Andy

Compromises maybe. Peaked response at the tuning frequency maybe? It's difficult to get 40Hz from a 4" driver with enough SPL to make it worthwhile.
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Old 4th September 2007, 10:13 PM   #15
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I simmed a small sealed with 4 of the W5-1138SM with unimpressive results. About 10db down at 40Hz.
Compound loading for these drivers is no better.
If you are looking for good response with good SPL at 40Hz from a small driver, it needs EQ.

Another possibility is to use a bigger driver with low Vas in a shallow down firing configuration. This could give the desired results.
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Old 5th September 2007, 12:19 AM   #16
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How about a larger driver in a ripole configuration?

mike
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Old 5th September 2007, 01:25 AM   #17
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Quote:
Originally posted by mashaffer
How about a larger driver in a ripole configuration?

mike

Yes, an N-profile ripole would fit the bill, given suitable drivers.
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Old 5th September 2007, 01:46 AM   #18
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Put the Red 12's into a smaller sealed box and then build a decent sub from 80Hz down or wherever the Red's go to?
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Old 5th September 2007, 07:45 AM   #19
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This is for a pair of 4" Eastech "subs*". You wouldn't have room for anymore. ~84 dB/1W, (*They really don't do midrange). I would expect them to run out of gas pretty early. I was thinking of trying 4 or 6 of them in a box with a 3" FR midbass.

dave
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Old 5th September 2007, 07:47 AM   #20
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Quote:
Originally posted by Brett
Put the Red 12's into a smaller sealed box and then build a decent sub from 80Hz down or wherever the Red's go to?
That is the best idea yet... you may want to do an aperiodic box to keep the Q down.

dave
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