My new & improved OB speaker

[audiophile36]

Hello I have been running my OB speakers with a single 4.5" fostex 126e without the help of a woofer for a while now because I didn't know how to cut large holes and quite frankly I liked the sound. To cut the holes for my Fostex I simply used a 4" hole cutter,but they only go up to 6" and I had no idea how to "manually" cut large holes...until I got the help of a fellow member who explained to me how to cut larger holes with my jig saw,I now have added an 8" helper woofer to fill in the bass a little.The woofer is salvaged from a pair of old Realistic Nova speakers,the magnet isn't that big so I figured it would do ok in OB. I haven't designed a crossover for them yet,but even without one they sound wonderful.I'm going to take what I learned with these and go OB crazy with larger woofers and different full range drivers...I'll keep everybody posted with pics!
[IMG][/IMG]

[Kensai]

Good, I was wondering if anyone had managed to get you some help.

OB all the way, and even with decent sized ones like that and maybe a bit of EQ, 8"ers are really just going to be mid bass drivers in OB. This will be something for you to play with for some time to come, and since you've started with decent FR drivers, it'll pretty much always sound good while you're at it.

Kensai

[audiophile36]

Originally posted by Kensai
Good, I was wondering if anyone had managed to get you some help.

OB all the way, and even with decent sized ones like that and maybe a bit of EQ, 8"ers are really just going to be mid bass drivers in OB. This will be something for you to play with for some time to come, and since you've started with decent FR drivers, it'll pretty much always sound good while you're at it.

Kensai

Thank's Kensai,

You are correct they still don't have super deep bass,but the bass they reproduce is great and actually has some nice impact.I could live with the bass from these 8 inchers for a long time with the music I listen too so I know a 12" or 15" would be icing on the cake.

[davidallancole]

Thats what I found too running 8s on my wider baffles. They are not the end all be all, but gives an idea of what is possible.

[peterbrorsson]

Hi audiophile36!

Interesting that you have blinds behind your speakers. This is something I have been thinking of, even if there are no windows behind. If larger wooden blinds are hung on the walls behind OB's, there should be some diffusion effect, so a closer positioning to the back wall would be possible?

Wadda'ya think experts?

Peter

[audiophile36]

Originally posted by peterbrorsson
Hi audiophile36!

Interesting that you have blinds behind your speakers. This is something I have been thinking of, even if there are no windows behind. If larger wooden blinds are hung on the walls behind OB's, there should be some diffusion effect, so a closer positioning to the back wall would be possible?

Wadda'ya think experts?

Peter

You are correct about the blinds...I had curtains behind the speakers but the absorbed to much sound,while the blinds diffuse the sound better.

[audiophile36]

here is the back of the speakers showing the neat wiring and binding posts.You know OB speakers sound better with neat wiring...LOL.

[IMG][/IMG]

[planet10]

Originally posted by audiophile36
here is the back of the speakers

If you open up the cutouts at the back it should improve things.

dave

[Tubamark]

Originally posted by peterbrorsson
Hi audiophile36!

Interesting that you have blinds behind your speakers. This is something I have been thinking of, even if there are no windows behind. If larger wooden blinds are hung on the walls behind OB's, there should be some diffusion effect, so a closer positioning to the back wall would be possible?

Wadda'ya think experts?

Peter

The rear distance requirement for dipoles has little to do with the nature of the rear wall; it has to do with creating the needed delay of that reflection. 3 feet (6 feet round trip from speaker to wall and back past the speaker again, on to listener) delays the rear reflection (at the listener seat) by about 6.75 miliseconds. It seems that lesser delays result in the brain integrating the reflection with the original/direct sound . . . sound at listening position is percieved as smeared across time.

If sufficient delay of the reflection exists, the brain says "ah-ha"- clear direct signal, and the reflection adds ambience and increased volume/SPL. Any diffusion is icing on the cake, but can't replace the needed delay. Only an anechoic front wall can do that.

Tons of writings and research out there on this topic. Maybe start with LinkwitzLab.com, as super-relevant to dipoles.

-- Mark

[peterbrorsson]

Originally posted by Tubamark


The rear distance requirement for dipoles has little to do with the nature of the rear wall; it has to do with creating the needed delay of that reflection. 3 feet (6 feet round trip from speaker to wall and back past the speaker again, on to listener) delays the rear reflection (at the listener seat) by about 6.75 miliseconds. It seems that lesser delays result in the brain integrating the reflection with the original/direct sound . . . sound at listening position is percieved as smeared across time.

If sufficient delay of the reflection exists, the brain says "ah-ha"- clear direct signal, and the reflection adds ambience and increased volume/SPL. Any diffusion is icing on the cake, but can't replace the needed delay. Only an anechoic front wall can do that.

Tons of writings and research out there on this topic. Maybe start with LinkwitzLab.com, as super-relevant to dipoles.

-- Mark

Hello Mark and audiophile36!
Thanks for the replies!

Mark, what I'm thinking is, if blinds are hung a certain distance from back wall, blades angled some degrees, there would be some benefits due to that the sound will be "bouncing" between wall and blinds. Thus causing a delay. Hope you understand my unscientific way of explanation. I shall read more of the links you provided.

audiophile, I've tested my fullrangers on an OB, wish I hadn't done that, now I hear just the boxes in my normal speakers.
The reason I ask about the blinds, is that my room, although large, do not permit OB's one meter from walls.

What the heck, I will try it later in spring!

Regards
Peter