Small box for FE103 - ML TL or ML TQWT?

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I have done the simulation for a small box base on Martin King's mathcad sheet (a big thank you, Mr King;) )

The result of the ML TWQT is attached. Any comments on this?
 

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I'd like to offer a comment; It seems for both of these that the bass levels start to fall away prematurely. It looks as though you are trying to hit 50 hz, and as a result the response below 100 hz is depressed by at least 3 db.

I made a similar mistake on my project (bigger mistake, yours might not hurt so badly) in underestimating the effects of a depressed bass response. The rule of thumb that I heard was that this sort of enclosure can play lower than the driver's Fs (not necessarily a good idea)- all the way down to 0.7*Fs.. any lower than that is a much worse idea. I think that you might want to consider moving your target cutoff a bit higher; to 60, 70, even 80 hz- and use a small sub.
 
Hi Joe,

thanks for the reply, but I am not trying to go low, but rather, try to have a smooth roll off as I have notice that there will always be quite a bit of room gain under 100Hz. A flat curve to 80Hz and sharp roll-off is definitly not desirable. At lease in my case.
 
See the recent threads about the "Locust 1.0". It's a MLTL using the FE107E, which is like the 103, but with shielding and a somewhat smoother response.

I'm listening to a pair right now, augmented with a sub crossed over at about 70 Hz. Good stuff.
 

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Dave Jones said:
See the recent threads about the "Locust 1.0". It's a MLTL using the FE107E, which is like the 103, but with shielding and a somewhat smoother response.

I'm listening to a pair right now, augmented with a sub crossed over at about 70 Hz. Good stuff.


They are real easy to build, using 3/4" material all around. The port is just a 1" hole in the front panel. Internal dimensions are H 19.5", W 4", D 5.5". Driver offset is 6". Port (hole) near the bottom.
 

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ChuckT said:
Hi Joe,

thanks for the reply, but I am not trying to go low, but rather, try to have a smooth roll off as I have notice that there will always be quite a bit of room gain under 100Hz. A flat curve to 80Hz and sharp roll-off is definitly not desirable. At lease in my case.

I'm using the Locust I's in a small room, and they are not at all boomy in the 70-100 Hz range. I have a peak at around 200Hz, but I think that's from a wall reflection. Those little speakers are simply not going to deliver loud, deep bass regardless of what kind of box you put them in. They are only 4" in diameter, and have a tiny xmax. I suspect that trying to stretch their low end response below 60 or 70 Hz would just create problems. I tried using them with some EQ on the low end, and they did not appreciate it! Now I use a sub with them, but on a lot of program material the little speakers sound fine all by themselves.

D.
 
nice designs dave. do you have any pics? those boxes 21" tall 7" deep 5.5" wide look like they can be made a bit smaller if i use 6mm AL instead of 21mm wood.

perfect to wall hang on either side of a plama tv.

now i was thinking of use 2 x 103 or 107 so that the BSC filter can be avoided and to get more bass SPLs.

maybe upfiring the second driver...
 
navin said:
nice designs dave. do you have any pics? those boxes 21" tall 7" deep 5.5" wide look like they can be made a bit smaller if i use 6mm AL instead of 21mm wood.

perfect to wall hang on either side of a plama tv.

now i was thinking of use 2 x 103 or 107 so that the BSC filter can be avoided and to get more bass SPLs.

maybe upfiring the second driver...

There's a picture in this thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=36305

They are still raw particle board, BTW.
 
ChuckT said:
Thanks, Dave. I will probably built a box very similar to yours. Guess I go with the ML TL box as there seems to be no advantage in using the TQWT.

me too.....with 2 modifications.
1. i am wondering about fostex introducing a FF105K (between the 85k and 125K) soon.
2. addding a second driver either on the top or bottom of the box to improve bass (compensate for BSC too) and sens.

obviously i cannot copy the box as is but am looking at something very similar.
 
navin said:


me too.....with 2 modifications.
1. i am wondering about fostex introducing a FF105K (between the 85k and 125K) soon.
2. addding a second driver either on the top or bottom of the box to improve bass (compensate for BSC too) and sens.

obviously i cannot copy the box as is but am looking at something very similar.

Those designs would go beyond "modification". Did you notice that the Locust I employs a BSC? Besides baffle step diffraction, I get a peak at about 200 Hz, probably from constructive bounce off the back wall. How is a second driver going to solve baffle step and early reflection problems?

Again, if deep, loud bass is what you are after, I don't think 4" drivers, either one or two of them per side, are going to be satisfactory.

I'm not trying to rain on your parade; I just wonder if you will really accomplish what you want with 4" speakers in a small box.

The Locust I sounds fine by itself on things like real jazz, string quartets and the like. I'm using a subwoofer to good effect for electronic music with deep, loud bass.
 
>How is a second driver going to solve baffle step and early reflection problems?
====
He wants to wall mount them, ergo no BS or early reflections of note. A second driver (preferably mounted on the baffle) wired in parallel allows a lower Fb to be chosen, with one rolled off at whatever point yields the flattest in-room response, or if a bit more impact is preferred, a slight 'bump' in the midbass (aka West Coast sound).

I've experimented with various wall mounted designs and found that making a wide cab that tapers to a slit vent on both sides works extremely well. For plasma TV apps though, making mirror image variants with the taper/vent on only side is probably better so that they can be butted up against it.

For a superior performance, though more woodworking intensive, then Herb's wallhorn is the 'Hot Ticket'. Hmm, unfortunately Herb's page is gone, but here's the text: http://66.102.7.104/search?q=cache:Urd2g2xvOtYJ:www.geocities.com/fuherb/wallhorn.htm+wallhorn&hl=en Basically, it was a wide/flat straight horn with the driver at ~ear height and the mouth terminating near the wall/ceiling junction to continue the expansion.

Anyway, dual FE107E should be able to get down to a usable 40Hz in a ~0.75ft^3 ML-TL, with adequate excursion/power handling for typical TV audio playback BW/SPL.

GM
 
Dave Jones said:
Those designs would go beyond "modification". Did you notice that the Locust I employs a BSC? Besides baffle step diffraction, I get a peak at about 200 Hz, probably from constructive bounce off the back wall. How is a second driver going to solve baffle step and early reflection problems?

i am not as mad as i look :) i am not expdecting a pair or 4" or even 4 of them to produce 100db at 30Hz.

however my goal is to build a speaker that is simialr to B&W VM1 or KEF KHT.

In Bombay, largely due to the show box apts we live in (average 2 bed. apt size is 700 sq. ft.), plasma TVs are what's hot. In fact the hot sizes are the 42" plasma or the 32" LCD. This in a country where mean income is about $300 per year! Go figure.

My goal is to build a speaker that will complement the plasma/LCD tv in WAF. I did not find the sound of the VM1 or the Bose acoustimass any good. The acoustimass sells here for about $2000!

GM is right. however i am planning / hoping to make one change to what he envisions. the second driver will be mounted on the top or bottom. this will automaitcally reduce the high freg. radiation into the room.

to further save internal volume I am investigating alternate materials (6mm thick aluminum C channel extrusion damped with rubber and lead sheets for example) for the box and maybe marble or granite for the baffle.
 
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