bipole lashup

[mrkramer]

I have 2 sets of single driver speakers. Both use the same TB 4" Bamboos. My intention is to take the drivers from one to use in a 3 way project Ive talked about elsewhere. Figured Id do a couple experiments with them first. Ended up putting one behind the other and driving it off my recievers 'B' channel. Sort of a poor mans bipole lashup. I was very surprised at the result.
To my ears it just sounded better. Fuller. More expansive. Larger soundstage. More lifelike. I had expected to loose imaging and Im not sure I did. When I switch back and forth the monopole version seems more "pinpoint" certainly but maybe more unnatural too. The bipole version just seems less hyper pinpoint. The speakers still seem to disappear either way.
How does this fit with other peoples experiences?


MrKramer

[sreten]

Hi,

Bipole arrangement automatically gives full bafffle step compensation
and therefore should sound "fuller", "bigger" "more lifelike" etc., the
extra rear radiation should not interfere with the frontal imaging too
much, especially if used well way from walls, usual for full BSC.

Possibly add a decent tweeter and try a 1st order series crossover ....

/sreten.

http://www.t-linespeakers.org/projects/tlB/index.html

[mrkramer]

"Bipole arrangement automatically gives full bafffle step compensation and therefore should sound "fuller", "bigger" "more lifelike" etc."

I had always thought of baffle step as a loss of SPL due to bass transitioning around the baffle. Therefore you could approach correcting it by equalization (which is what Im currently doing) or an extra ".5" woofer on the front or with a BSC filter.

The effects Im hearing do not seem to be related to SPL i.e. more bass or more equalised response across the spectrum. I read through the link you sent I was struck by the idea of delays and how we percieve them.

I wonder, are there key frequencies where the effect of rear radiation is more pleasing? Reading up on open baffles seems contradictory. Some seem to champion all dipole, others Bass, others Mids. Some say a rear tweeter is critical others say leave it off.
Are the rules of thumb for this different between Dipole and Bipole?

Any Bipole fans out there?

[sreten]

Originally posted by mrkramer

I had always thought of baffle step as a loss of SPL due to bass
transitioning around the baffle. Therefore you could approach
correcting it by equalization (which is what Im currently doing)
or an extra ".5" woofer on the front or with a BSC filter.

Hi, you've lost me ... a bipole does not need correcting by EQ for BSC, /sreten.

[Each driver radiates into 2pi, so they cannot go from 4pi to 2pi, ergo no BS]

[mrkramer]

Sorry, poor wording.

I thought you are implying that the reason for the bigger fuller and more lifelike sound is due to its inherent BSC.
I think BSC is more of a SPL issue. Am I incorrect?
It seems to me that what Im hearing is due to the nature of the delayed reflections from the rear driver.

Still curious if there are any rules of thumb regarding bipoles and whether or not they are the same as apply to dipoles.

That link had really interesting info regarding the delay and direction of reflected sound. What about the frequency? For instance: I use rear tweeters on my speakers. The effect to me is "airiness".
Does frequency response need to be the same on the front and back? I suspect not but its just a hunch.