So, I had this idea to put a pair of drivers I had lying around into use and go for a somewhat unusual design that seemed to offer a couple of advantages. Unfortunately it sounds awful and there's hardly any sound coming out of it. My guess is that the port is too long or the drivers are mismatched and cancel each other out.
Drivers: Celestion T1600, Fs: 22Hz
Cabinet:
outer dimensions: 40x40x30cm
inner dimensions: 27x27x26cm
port: 140x26x3cm
What do you think is going on here? I may be able to shorten the port if that is the problem. Can somebody run this through a simulation and give recommendations on how to save this design, please?
Pics:
Drivers: Celestion T1600, Fs: 22Hz
Cabinet:
outer dimensions: 40x40x30cm
inner dimensions: 27x27x26cm
port: 140x26x3cm
What do you think is going on here? I may be able to shorten the port if that is the problem. Can somebody run this through a simulation and give recommendations on how to save this design, please?
Pics:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
No, The Volume behind this Driver should optimally be ~118 Liter and the Box fb= ~28.4 Hz for a f-3dB of ~32.4 Hz, so the main issue is the wishful thinking of a too small Compliance Volume.
b
Hi diyordie,
These speakers (Celestion T1600, I used bjorno's T/S values) do not have a lot of motor, and require a large enclosure volume. I have taken speakers like that and mounted them isobarically to reduce the required volume. Play around w/ the idea of an isobaric bass reflex (vented) box. I'll attach a Hornresp Input screen, and the respective SPL chart. Use at least dual 3"I.D. ports as indicated in the Hornresp example.
Regards,
These speakers (Celestion T1600, I used bjorno's T/S values) do not have a lot of motor, and require a large enclosure volume. I have taken speakers like that and mounted them isobarically to reduce the required volume. Play around w/ the idea of an isobaric bass reflex (vented) box. I'll attach a Hornresp Input screen, and the respective SPL chart. Use at least dual 3"I.D. ports as indicated in the Hornresp example.
Regards,
Attachments
I also was under that wrong idea long ago and it simply does not work that way.
I make Bass amplifiers, including cabinets and even the speakers themselves and thought I could make truly portable ones going along that path: making a small cabinet and then adding the necessary port to tune them for good bass ... they were weak and puny, period.
At least in the MI area of Cabinetry I believe more and more that at the lowest frequencies: "the cabinet is the actual speaker that people hears and the electromechanical speaker is just the "cabinet exciter" "
Or like Formula 1 Racers say: "there is no substitute for cubic inches" (in that case, in car engines) .
No kidding: grab a hammer and knock off all the internal sub-walls except the bottom shelf one, then have a listen.
On second look, even the bottom shelf is too long.
You can not compensate for a too small volume with a humungous port.
*Maybe* you can "tune" it to what seems to be a useful frequency , but that tuned cavity won't properly couple to the speakers and radiate useful acoustic energy.
Now you have: "a too small box with a too long port", not a proper "tuned cabinet" if this makes any sense to you.
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Hi diyordie,
Post #14: "...extending the 1.4m port to 3 / 3.4 / 3.8m and make it a TL?..."
This will not work for the above mentioned reasons.
Hornresp is free, available here: Hornresp
See: Post #4 for an example of your box in Hornresp by bjorno. Go into the Hornresp Wizard, and start changing L45 (the port length) to see what happens.
For comparison see: Post #12 for a Hornresp example of your drivers in an isobaric arrangement in a vented box.
Your driver requires a large enclosure, you can reduce the enclosure requirement by arranging the drivers isobaricaly.
Regards,
Post #14: "...extending the 1.4m port to 3 / 3.4 / 3.8m and make it a TL?..."
This will not work for the above mentioned reasons.
Hornresp is free, available here: Hornresp
See: Post #4 for an example of your box in Hornresp by bjorno. Go into the Hornresp Wizard, and start changing L45 (the port length) to see what happens.
For comparison see: Post #12 for a Hornresp example of your drivers in an isobaric arrangement in a vented box.
Your driver requires a large enclosure, you can reduce the enclosure requirement by arranging the drivers isobaricaly.
Regards,
I would agree with that.
I haven't used chipboard for a cabinet for about 35 years.
I made a cabinet out of veneered chipboard in about 1980 for a mobile disco.
Of course it got wet being carried into a gig and fell apart.
I always use 18mm plywood these days.
An externally hosted image should be here but it was not working when we last tested it.
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