Best Full Range for 1.64 Liter Small Cabinet

[Ben_Tech]

Hi again everyone! Here I am again with my questions. Thank you for your patience!

I simmed a number of small full range drivers in a nifty sealed 1.64 liter cylinder enclosure I have, and here's what I came up with:



The orange line is the Fostex FF85WK (Qtc 0.70)
The green line is the Fostex FF105WK (Qtc 0.82)
The red line is the Fountek FR88EX (Qtc 0.63)
The light blue line is the Alpair 7 (Qtc 1.05)
The yellow line is the Alpair 6M (Qtc 0.75)

As you can see, these small drivers all appear to roll off below 150-200 Hz in such a small enclosure. The cabinet is sealed. I could add a port tube if it's very short. Ideally, I'd like to make it down to 100 Hz to cross to the subwoofer at that frequency. Not possible in such a small cabinet?

What about room reinforcement? They will be near a wall... any help there?

Am I missing a good driver for this application? If so, please mention the model number in your reply.

Also, would the 'honking'/'boxy'/'cupped hands' problem, if any, be eliminated or mitigated by the sides being round (it's a cylinder as mentioned and the driver is mounted in the end of it)?

[chrisb]

It sounds as if you intend to mount the driver at the end of the tube - what is the ID?


Of the drivers listed, I think the 2 most likely to work well in this application would be the FF85WK and the FR88EX.

I know that Dave has played with something along the same lines, I think with a small Alpair and SEAS FR?

[Ben_Tech]

Thanks Chris - the ID is 4-7/16" or about 113 mm.

I like what I have read about the FF85WK, but not sure with its very small xmax and size if it would make it to 100 Hz in such a small cab. Maybe in-room they do? What about 150 Hz?

I have the Founteks (they are playing right now actually) and they sound quite nice (different cab though and I don't want to take them apart to experiment, unfortunately). I would not mind a little bit extra vocal intelligibility though and it sounds like the other drivers mentioned might provide that.

[Ben_Tech]

PS The xmax issue is why the Fostex FF105WK sprang to mind as it has 1.7mm instead of 0.35 on the FF85WK. I just don't know if it has the 'magic' of its slightly smaller brother.

[planet10]

Originally Posted by Ben_Tech

As you can see, these small drivers all appear to roll off below 150-200 Hz in such a small enclosure. The cabinet is sealed. I could add a port tube if it's very short. Ideally, I'd like to make it down to 100 Hz to cross to the subwoofer at that frequency.

The issue with venting it, is that the vent is of significant size.



Here is 1.5 litre box (+ driver + vent). The box could be shrunk by using a 5/8", 3/4" or1" tube instead (recalc the length and subtract the reduced vent volume from the extent of the box. A small enuff vent could avoid the bend if exiting out top or bottom.Changing Port Size

Simulation shows F3 @ 100, F10@70 with a bump (1 dB or so) before it starts dropping.

dave

[Ben_Tech]

Thank you, Dave. I've always admired your drafting skills. The thing is, the Alp 6 and Alp 7 and the others all seem to sim about the same in this small cylinder box. With a port, the only place it could go is on the back of the cylinder facing the driver, which will surely transmit midrange frequencies out the back. So, probably sealed.

For example, (all in 1.64 liters):

Alp 6M vented F3 = 99 Hz (port tuned to 65 Hz, 3/4" x 4.22")

Alp 6M sealed F3 = 117 Hz (Qtc 0.75)

Alp 7 vented F3 = 102 Hz (port tuned to 60 Hz, 3/4" x 5.05")

Alp 7 sealed F3 = 106 Hz (Qtc 1.05)

So, I guess the real question is, would the in-room results sound thin and not reach 100 Hz or even 150 Hz in practice? Sometimes there is a big difference between theory and practice! What about room boundary reinforcement, does that come into play?

[planet10]

Originally Posted by Ben_Tech

With a port, the only place it could go is on the back of the cylinder facing the driver, which will surely transmit midrange frequencies out the back.

Actually, given that you probably haven't accounted for the driver volume (i'm guessing), you would probably need to stick it out the back (ie external).

Alp 7 sealed F3 = 106 Hz (Qtc 1.05)

That Q too high, and makes getting anything vented not a real option.

and F3 is not really that useful an indication sonically... F6 & F10 are more important.

dave

[mondogenerator]

Qtc of 1.05 is a little high, but hardly prohibitive. In practice it may benefit

[Overkill Audio]

You could try the 4.5 inch BMR 's, they are really good, way better than the smaller units.
Also the Neo magnet version has lots of clear space behind the magnet, the Ferrite version has no room. You can easily hear the difference and its well worth paying the extra ( Neo is abbout twice the price of Ferrite) for the Neo.

I have been getting fab rusults in a 2 litre sealed cabinet, 8 drivers per channel in the attached design, up to 18 per channel in another version with edge to edge driver fitting.

Just as a point of reference, in the same enclosure the 4.5 inch BMR has way better bass and midrange than the Alloy Ted Jordan units, the TJ goes higher ( but is a bit rougher) in the top.
Hope this helps
Cheers
Derek.

[Boscoe]

Originally Posted by Overkill Audio

You could try the 4.5 inch BMR 's, they are really good, way better than the smaller units.
Also the Neo magnet version has lots of clear space behind the magnet, the Ferrite version has no room. You can easily hear the difference and its well worth paying the extra ( Neo is abbout twice the price of Ferrite) for the Neo.

I have been getting fab rusults in a 2 litre sealed cabinet, 8 drivers per channel in the attached design, up to 18 per channel in another version with edge to edge driver fitting.

Just as a point of reference, in the same enclosure the 4.5 inch BMR has way better bass and midrange than the Alloy Ted Jordan units, the TJ goes higher ( but is a bit rougher) in the top.
Hope this helps
Cheers
Derek.

Which BMRs are these?