Why does the bass disappear the further back I go from my new speaker?

[adason]

Yup...

Plus we are talking about real subwoofers, 15" and up, with real response down to 25Hz.

 

[scottjoplin]

Dipoles, two subs for the price of one 😉

 

[adason]

Yes, but they need to be equalized, due to cancelation, they are not flat by design.

 

[planet10]

Internally, they're 430mm tall, 150 wide and 200 deep. The cross sectional area is a little bigger than the Sd of the driver, and they have a 2:1 taper ratio.

Sounds like you designed based on Classic formulations. That will usually not give anywhere near an optimum line. What driver(s)?

dave

 

[smart51]

I'm using Tang Band W4-2142s. I was going to use W4-1879s but they're 3 times the price and the 5Hz lower F3 is less than 2 semitones.

What parameters would give a better line? More taper? More cross sectional area?

 

[planet10]

W4-2142 - 4" Paper Full Range - TB SPEAKER CO., LTD.

We have the 1879. Quite decent but overly coloured in my opinion.

To do a proper line it should be modeled. A competent experienced designer should be able to get quite close to optimum before cutting any wood.

You have to look at the driver in its box to know what its extention is. F3 is a useless indicator for humans. Look at F6/F10.

dave

 

[Dave Bullet]

as you move further away from your speakers, I assume you are moving closer to the wall behind you (listening position) = cancellation may result.

 

[celef]

Near a wall, if it is hard enough, bass will be boosted. if you place the speakers and you at a certain areas within the room you can get an even bass response, but if the walls are flimsy those areas will be offset

 

[adason]

I built some large transmission line speakers a while ago. The bass response is epic, but they are quite large. So I've had a play with making a compact transmission line. Stood half a metre away, they're quite good. Two metres away, though, and the bass halves in volume. You can still hear that the deep notes are there, but just quieter. What's going on? And can it be fixed?

Perhaps try this approach: place your transmission line speaker exactly in your listening position, and then walk around the room and listen, when you find the corner or place where its sounds good. Then move the sub there...

 

[jan.didden]

Very good advice!

Jan

 

[Disco-Pete]

A second pair of speakers in the same room not being used cannot help but be the largest influence with this problem. You have a much larger speaker virtually sucking up everything the smaller one is doing, sub or no sub.

 

[smart51]

Sounds like you designed based on Classic formulations. That will usually not give anywhere near an optimum line. What driver(s)?

dave

The design is fairly optimal given for the size of enclosure. For fun I made a quick and dirty plywood cabinet for the driver today to see how much better a fully optimised line would be. The new cabinet is twice the size of the old. The bass is fuller than in the smaller box. Given the Fs of the driver, I'm pleased with the result.

So the answer to the original question is yes, you can make a small TL speaker, and it will give more bass than the same driver in a reflex enclosure, but it won't be as good as it could be with more volume to work with.

 

[planet10]

So the answer to the original question is yes, you can make a small TL speaker, and it will give more bass than the same driver in a reflex enclosure, but it won't be as good as it could be with more volume to work with.

That is probably not an accuarate generalization.

Did you actually model the line to see what would be optimal?

dave

 

[smart51]

That is probably not an accuarate generalization.

Did you actually model the line to see what would be optimal?

dave

Yes. It's dangerous though. Hours go by when I'm playing with the software.