High and wide enclosure?

[oLjud]

Hi all,

I just sketch up an enclosure for my upcoming speaker project and would like to share the plan for inputs on the design.

Woofer: Beyma 12G40
Tweeter: Beyma TPL150

The box has a ~60L volume (minus the driver and port) which would end up approximately at 55L. I put two ports in the bottom, 17x5cm and 20cm high, which should give f3 at 48-49Hz.

I know it's a different style of cabinet, but I like the "design" of a high and wide enclosure much. I was first planing to place the port in the bottom front but it mess up with the looks, I think....

Crossover point will most likely be at 1200-1300Hz.

What whould you do different ?

[planet10]

Do keep in mind that the tall aspect ratio makes this an ML-TL and not a bass reflex, so box tuning cannot be modeled with a standard box simulator.

dave

[oLjud]

true! not thought of that actually.
But if I place the ports in the midheight of the speaker, what it make a difference?

[planet10]

It is still an ML-TL just not an optimum one.

Certainly worth $25 for the MJK Software

dave

[oLjud]

mm must get MJK mathsheet, seems really great!

[oLjud]

How good is Hornresp on MLTL enclosures?
I tried yesterday to simulate the speaker with a port and it was possible to get a great bassrespone. But can i trust hornresp?

[GM]

Originally Posted by oLjud

I know it's a different style of cabinet, but I like the "design" of a high and wide enclosure much. I was first planing to place the port in the bottom front but it mess up with the looks, I think....

What whould you do different ?

How good is Hornresp on MLTL enclosures?

Me too. I try to use at least a 30" (76.2 cm) wide baffle (or add side 'wings' to get it) when I can as this usually is wide enough to not need any baffle step compensation (BSC) if the speaker is < ~2 ft from a wall.

At a glance, nothing, though not sure what section B-B is telling me..........

HR assumes infinite rigidity, etc., so doesn't account for any real world losses or effects on added damping like MJK's software does, but is good enough to use as long as your plan is to only minimally damp the speaker; so if a high stuffing density is required, then I can't recommend it as it will typically calculate a much too long vent.

Also, it won't give you any idea whether the vent system's total area is adequate for low compression at highest power expected around/at Fb, so this must be calculated first.

Again though, if a high stuffing density is used, a smaller vent area can in theory be used, ergo an even shorter vent, but what can happen is that the calculated vent length can wind up thinner than the baffle, so an even larger vent area is required just to make it a baffle thickness vent.


Bottom line, for TL, MLTL, etc., best overall to just get MJK's software, use the demo from his site if you don't want to pay for MathCAD and save your designs in WORD or similar and use HR for the various band-pass and horn types that it's designed for.

GM

[oLjud]

My main idea is to only add stuffing right behind and around the woofer and use as little as possible everywhere else.

I just simulated on Beyma 10G40 instead of 12G40, it requires less volume and I only loss about 5Hz in bass response, from 45 to 50Hz. The speaker should be able to play max around 110dB but over that it's just a bonus. And according to my simulates its no problems...

[GDO]

My main idea is to only add stuffing right behind and around the woofer and use as little as possible everywhere else.

Don't dream too much, Tls are stuff made of stuffing...

[oLjud]

Originally Posted by GDO

Don't dream too much, Tls are stuff made of stuffing...

I know, I built a TL-speakers before
But I also read that MLTL aren't as sensitive to stuffing as TLs are. So I start off with almost none stuffing and work my way to the "perfect" stuffing amount.