S8 Open Baffle using 6 Jaycar woofers

[pedroskova]

Originally posted by dzzmiller


Interesting. What are the woofers? Do you use two of these units?

Yeah, it's stereo. They serve as pedestals for the other baffles, and are part of a 4-way tri-amplified active system. The drivers are Elemental Designs 2 ohm drivers wired in series. I had originally intended to wire them series/parallel, but the QSC PA amp driving them is so sensitive (compared to the other amps) that I didn't have to go that route.

[ttan98]

Originally posted by dzzmiller


The DE10 is reputed to be close to the 250 and is 1/3 the cost. All the non-metalic B&C in that 1" range are likely decent for hifi use.

As far as the horn crossover, the waveguide is at least as important as the horn in determining how low you can go.

I have both DE10 and DE250, both are excellent, value for money, DE10 min xover 2.0Khz and De250 Min 1.5Khz, I think DE250 is better. If you are on a budget DE10 is good enough.

[ttan98]

Fergs1,

This is my implementation of De250 and RCF horn with 10" woofer.

Notice it is a BR implementation, horn I have tried open baffle with equal success.

Cheers

[gainphile]

Originally posted by fergs1
Greetings Gainphile, I gotta say I admire your tenacity.Ive been quietly watching your various takes on OB since you did that number with "found" speakers and its been very entertaining.How does the bass compare on the s8 compared to the s7 as I'm running alpha 15's with visaton b200 and I really like what the alphas do. I'll have to try them in a h-frame when I get the energy to biamp them.So little time at the moment with 18mth twin boys and their 4.5 yr sister leading the mayhem 8-) Anyway I'm enjoying your journey so thanks for sharing.

Thank you . I have forgotten how long it has been since I found those hard rubbish speakers, which I still have for historical reasons

I like the midrange smoothness of S7 much better. But this maybe because I'm too lazy to drag the speakers outside for measurement and tune the XO. But low-end integration is better. I guess separating the main panel and woofer had some detrimental effects on polar response in hindsight.

The bass of eminence alpha is better, no doubt. The jaycar bottoms quite early. But I have not activated the last pair due to lack of amps. I have sold all my alphas as any future projects would be about thinner baffle width. Maybe an array of 8 5" woofer or something

[gainphile]

Originally posted by ttan98
Fergs1,

This is my implementation of De250 and RCF horn with 10" woofer.

Notice it is a BR implementation, horn I have tried open baffle with equal success.

Cheers

Ttan...that's interesting. I have a 10" round waveguide but have no experience in working with them. Did you have to import DE10 or are they available locally ?

[ttan98]

Originally posted by gainphile


Ttan...that's interesting. I have a 10" round waveguide but have no experience in working with them. Did you have to import DE10 or are they available locally ?

Find a friend who lives in the States, ask him to buy on your behalf and send them to you. Cheaper this way, you can get them locally but TOO expensive.

PE is the best place to buy B&C ie DE10 parts.

[danne666]

try sending a m ail to audiocomponents.nl

they can get you more or less any brand for about 20% lower price than you would pay anywhere else. Exelent service and as fast as they come.

But you need to send them what brand/driver you need and they look it up for you.

[gainphile]

I pulled out my fingers last night so here's some update:

I attached small side panels to provide bracing to the baffle. Without it the speakers sways on loud bass passage.




I also took out my measurement tools. As expected the large baffle width relative to the midrange dragged the dipole peak lower, which in effect put peak and dips below crossover XO. This, unfortunately is a design constraint.



The dipole peak at around 500Hz will be easy to equalize. Not ideal are the peak and dips at 880Hz, 1.2kHz, 1.8kHz this is something I have to live with unless there is a magical way to shrink the baffle width to around 19cm as in S7.

This irregularities manifest itself in female vocals. I imagine replacing the 5" P13WH with larger driver such as 8" W22EX may make better situation. But I'm not convinced. Perhaps that's why SL did not provide measurements for Orion? I would also be not sure of the accuracy by using drivers installed on a wide baffle (B200+Alphas, etc.) because unfortunately the dipole peak coloration can be mistaken for resolution/openness by the ears.

This leads me to believe that the most realistic sounding OB would be something thin like S7, but with an array of smaller woofers to get the bass. I am no longer convinced that separating main and bass panel is good for polar response (but I may still investigate beethoven-style approach). The small woofers needs huge XMAX and Low FS like those used in Pluto (Seas 5") and unfortunately they are very expensive and we may need 4 of them per channel.

Very interesting to note that ealier prototype from SL tries to narrow down the midrange section as well as in "L07 Dipole"



http://www.linkwitzlab.com/design_of_loudspeakers.htm

not sure at what stage he does not think this is important anymore.

[ttan98]

Hi,

You may want to consider using Eminence beta 8A(8" and 94dB spl) not that expensive, this driver is used by Gary Pimm.

There is a new shipment on the dock at the moment, I suspect the price would be about AUD$120 each. If interested I will provide details.

[ttan98]

Hi,

I thought of sharing my implementation OB using GR drivers M130 in MTM and DE10 mounted on ME10 horn.The twin woofer is mounted on a U-frame. The frame in which they are mounted are for testing and will be mounted on a new frame, still in construction. I use DCX2496 hence equalization on all drivers are not that difficult.

Enclosed is a picture taken together with another speaker in BR cabinet.