Help needed! Where to start with open baffle speakers

[Macca]

Interesting. Which hi-fi rules do you consider to be bollox? I ask because I agree with Scotty when he says "ye canno' change the laws of physics, captain".

One for a new thread I think.

[fatmarley]

That's interesting that there is now a bass unit made specifically for OB use.

Just had a quick look at the specs and It looks like a cracking driver for open baffle use. Couldn't see a frequency response graph though...

[vintage60]

Matt - may mate Dave said the same thing as you about the Eminence Alphas...they were boomy and had muddy bass. He also tried Lowthers (I don't know which ones) and some others. Said AE Dipole 15s were the best of the bunch (really, really good). He also said that the drivers in Voxativ speakers are great, but you need to be a millionnaire!

[Arkless Electronics]

Just had a quick look at the specs and It looks like a cracking driver for open baffle use. Couldn't see a frequency response graph though...

Yeah the big problem is that woofers for OB need pretty specific characteristics and as there is no market for such things beyond a few audiophiles non have been built... until this one it seems.... I would have thought a foam surround would make it better still but there's the old rot problem..

[petrat]

Don't be put off by room restrictions. I have broken all the above guidance in that I fire across the narrow dimension of my room and listen in the near field. Baffles are barely 1m off the rear wall but are angled inwards which I think 'disrupts' the rear reflections reducing cancellations.

Yes, Chris, but your set-up takes 'near-field' to a whole other level ... probably more accurate to describe your OBs as very large open-back headphones

[paulf-2007]

Has anybody measured the spl from the rear of a driver in open baffle and compared it to the measurement from the front. I suspect it would be less from the rear. A driver pushes air and due to the cone shape must move more air at the front than the rear, the rear is shaped more like an arrow head compared to the front. I ran open baffle bass 2' from the wall with no loss of spl. On the other hand I accidentally wired my zu omen speakers out of phase and lost the bass very noticeably. What seems logical in theory doesn't always work in practice.o

[fatmarley]

Matt - may mate Dave said the same thing as you about the Eminence Alphas...they were boomy and had muddy bass. He also tried Lowthers (I don't know which ones) and some others. Said AE Dipole 15s were the best of the bunch (really, really good). He also said that the drivers in Voxativ speakers are great, but you need to be a millionnaire!

Looks like you've got your woofers sorted then. Just need to decide on mids and tweeters (assuming you want to start with a 3 way)

[fatmarley]

I would have thought a foam surround would make it better still but there's the old rot problem..

Foamed rubber Is almost good apparently. Doesn't rot either.

[Macca]

Has anybody measured the spl from the rear of a driver in open baffle and compared it to the measurement from the front. I suspect it would be less from the rear. A driver pushes air and due to the cone shape must move more air at the front than the rear, the rear is shaped more like an arrow head compared to the front. I ran open baffle bass 2' from the wall with no loss of spl. On the other hand I accidentally wired my zu omen speakers out of phase and lost the bass very noticeably. What seems logical in theory doesn't always work in practice.o

Isn't there something in physics about an 'equal and opposite reaction'? You lose bass frequencies progressively as the out of phase return wave cancels the forward wave. So you lose bass, not spl. I think it works out that to cancel down to 40 Hz you need a 20' wide baffle. You'll get the harmonics which is why it will subjectively still have bass, but you won't get the fundamentals.

[fatmarley]

Yes, Chris, but your set-up takes 'near-field' to a whole other level ... probably more accurate to describe your OBs as very large open-back headphones

I like near-field listening. You get more of the direct sound with less reflections. Reflections really mess up the sound.

Some old Epos ES11 I had years ago were absolutely bristling with energy when I had them set up near-field (not at all harsh either). Moved them downstairs to the main system (mid to far-field) and they transformed Into dull, boomy, lifeless things.