Bookshelf dipole speakers - is it possible ?

[gainphile]

Having owned an open baffle speaker, I found it irritating to listen to my floorstanders in the study room. So over the weekend I built a "bookshelf open baffle" with some degrees of pessimism.



But bass aside, I was blown away with its sound signature. They are as open and natural as my larger dipole (the size is about half a door)

I have retired my floorstander as a result, and so the question remains: how to fix the bass. I tried normal subwoofer and was dissapointed. Some obvoious experimentation will follow such as
- active equalization
- dipole subwoofer (h-frame, u-frame??)



But with space constraint I'm not sure if it's possible for mini-dipole to have good bass ???? help!

[bonjonno]

nice OB's gainphile! I have been fooling with some recently. Currently have a 10" Lil Buddy and B&C horn. Sounds quite good. Couldn't get good bass with either an OB or a boxed subwoofer. So I'm using them both. The box is about 60 ltr ported and adds tremendous bottom. The 15" OB is the woofer part of a silver iris which is similar to an eminence alpha I believe. Tho it's much higher efficiency than the boxed woofer, the combo seems to work. I'm driving both woofers with one amp; just under 3 ohm load. The 10" LB and horn are powered with my better amp. Once you get the OB bug it is hard to go back.

[nunayafb]

Don't know how much it will help but I would experiment with about 4-6" deep wings and stuffing to damp out the rear wave. Basically a short heavily damped u-frame, focus more on damping the sides near the wings and less right behind the driver and above it.

Minimal cost and effort and it might be enough for nearfield listening.

Let me know how it works out.

-J

[gainphile]

Bonjonno, that's a massive system it must sound a real treat. Yes I've been querying the Hawthorne coaxials but with my room size I don't think it's going to happen. I can do that with my living room setup but it means fighting with my kids' power ranger sessions

Bonjonno, thanks that's a great idea. It just so happen that I have a pair of 10" lying around. I will try to add this into the system. Now, about the wings, is there any particular calculation I need to follow (why 4-6"?) -- and is it better using H or U wing ?

[nunayafb]

the 4-6" was based on the appearance of how much space there is behind your baffles. The wings almost make it a U-frame, minus the roof. The important part is going to be the damping, I would keep adding more until it adversely affects the sound then pull a little out. You will basically be experimenting with over stuffing to damp the low frequencies while moderately stuffing above and behind for the mid band. At some point you should approach a cardioid type radiation pattern, which will solve your bass problem. Notice I said should, with only 4-6" I don't know if over stuffing will accomplish the goal.

[navin]

Originally posted by bonjonno
nice OB's gainphile! I have been fooling with some recently. Currently have a 10" Lil Buddy and B&C horn. Sounds quite good. Couldn't get good bass with either an OB or a boxed subwoofer. So I'm using them both. Tho it's much higher efficiency than the boxed woofer, the combo seems to work.

nice system. What woofer is in the boxed woofer?

Does the bass quality of teh selaed box woofer and OB integrate well? How much more sensitive is the Iris than the boxed woofer?

My object is to use 2 Augies (or similar woofers) mated to a OB midbass (Supravox 215) and tweeter (B&G Neo 3), I wonder if I would need a selaed box woofer to augment the bass for this.

[bonjonno]

thanks navin. The boxed woofers are loaded with 10" dvc madisound woofers. I've used them for years. Had them in the corners and they were great, but had to move them in to support my OB project. They really make the system sound huge, but are boxy sounding. That isn't a bad thing, but it doesn't integrate so well with the wide open mids and highs. The OB 15" has a wonderful string bass sound, but not much bottom on electric bass or kick. No slam. Together they get the job done. I think the 15 is rated at 98db and 10 is about 90db. But the vented box adds alot.

I've not heard the augies, but from all I've read they seem to have all the low impact the SI's are missing. They are not nearly as efficient tho. Need lots of watts. When I save up some more loose change I may try a couple of selenium PW315 15" woofers. Four can be had for less than 2 augies and they are very efficient.

[blue934]

Gainphile, could you describe your bookshelf dipole in detail? it looks very interesting.
blue934

[mashaffer]

Maybe you just need to use some really cheap 10" bass drivers. You know the kind with Q approaching 2.

mike

[ttan98]

Originally posted by bonjonno
nice OB's gainphile! I have been fooling with some recently. Currently have a 10" Lil Buddy and B&C horn. Sounds quite good. Couldn't get good bass with either an OB or a boxed subwoofer. So I'm using them both. The box is about 60 ltr ported and adds tremendous bottom. The 15" OB is the woofer part of a silver iris which is similar to an eminence alpha I believe. Tho it's much higher efficiency than the boxed woofer, the combo seems to work. I'm driving both woofers with one amp; just under 3 ohm load. The 10" LB and horn are powered with my better amp. Once you get the OB bug it is hard to go back.

How do you find the driver Lil Buddy? What does it sound like? Magnetar seems to like it.

Looking at the FR curve it rolls off quickly around 150Hz. Your woofer and Lil must x-over at higher than 150Hz.