Building new dipole system, need comments

[5th element]

Konnichiwa,



No, the H-Baffle is not very ameanable to this type of "milkmaid" calculations. Actually, not even a simple rectangular baffle is, especially as you MUST include roll effects.

If you want to know how an H-Baffle works try simulating as short transmission line, then add room effects.

Sayonara

Ill just build then measure them then

But as a general rule of thumb is that how you could calculate the frequency extension of the baffle? Linkwitz seems be be having less and less information on his website available to the public.

 

[ThorstenL]

Konnichiwa,

Ill just build then measure them then

Good idea.

But as a general rule of thumb is that how you could calculate the frequency extension of the baffle?

Rules of thumb (as commonly published) I noticed give results that are hugely wrong and overstate the real requirements for baffle area. This has got a few reasons, but basically as for any other speaker type, any simulation is WRONG if does not account for basic room interactions and driver response. These are a bit more complex for a dipole than for a sealed box (or reflex) and they are a bit more complex most average T/S derived response simulators suggest.

Now even a plan baffle is actually still a simple structure for mathematical analysis, H-Baffles and U-Frames really make the life interesting however.

Actually, any form of simulating speakers is quite prone to error, even the simplest boxes are actually quite interesting to analyse and similate.

Sayonara

 

[akunec]

Another reason that I chose such a high xo frequency (8k) is because of where 8k lies on the equal loudness contours... A tone at 8khz must be 10-15 dB louder then at 2khz be be heard as equally loud... Therefore imperfections in the xover network will be 10 dB quieter... I also believe 8khz is a less critical region then 2k.

Size is also a major concern... I would love to use some 15 in drivers but they are too big for me at this time.

Thanks for the comments guys!

Alex

 

[catapult]

Linkwitz seems be be having less and less information on his website available to the public.

That was just a brief bandwidth problem. He has a new ISP and the whole site is available.

 

[rick57]

B & C 15 PK

Hi jmikes

The 15 PK 40 looks a very good driver. I suspected a catch –it’s $555.
If I was going bigger $ I’d probably go a PHL 5240 – a very good 15 inch at $399.

Thanks anyhow

 

[Bill F.]

Size is also a major concern... I would love to use some 15 in drivers but they are too big for me at this time.

What are your planned baffle dimensions? If you're planning on narrow baffles, unfortunately that means you might need to further increase your dipole displacement beyond my suggested 4x rule of thumb, since cancellation will begin at higher frequencies. Folding, H/U baffles, etc. can address the pathlength cancellation issue, but they introduce quarter-wave resonances and spatial radiation transitions that can be difficult to predict. I'm not saying it can't be made to sound good, it just quickly becomes a complex EQ issue.

 

[jmikes]

Re: B & C 15 PK

Hi jmikes

The 15 PK 40 looks a very good driver. I suspected a catch –it’s $555.
If I was going bigger $ I’d probably go a PHL 5240 – a very good 15 inch at $399.

Thanks anyhow

Parts Express has it for $158. 15pk40

 

[5th element]

Im not entirely sure what you guys idea of loud is.

I have just finished making my H baffles which are 60cm tall, 33cm deep and 28cm wide. Now these have a single XLS10" in them and go plenty loud enough and I like things which can go loud on occasion. I had my dad listening with me and we had to raise our voice sitting 3 meters away and we were next to each other. The XLS still had plenty of excursion left too.

I understand that im in a 3*4 meter room and that makes a difference. But the comments about needing lots of 15" to get decent levels is maybe true for you, but im sure most people would be happy with the levels of bass im generating in my room, it goes plenty loud to go past being socially acceptable.

On another note its some of the best bass I have ever heard, so if you want to try openbaffle bass, just do it.

 

[Bill F.]

On another note its some of the best bass I have ever heard, so if you want to try openbaffle bass, just do it.

Wholeheartedly agreed. You never know 'til you try.