Dipole speakers. Dual 7 or 8 inch drivers?

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I'm in the planning stages for an Orion-like dipole speaker. After the release of the Dayton Reference subwoofers I'm getting very anxious to get this project rolling. I'd like the woofers to work as little as possible, so I will be going with dual 12 inch High Fidelity Dayton RS sub. I will be sticking with all Dayton drivers and am "stuck" at the moment.

After reading about Monte Kay's RS Dipole speakers (http://www.mfk-projects.com/rs_dipole.htm) and seeing how he used dual 7" RS180 woofers, I got to thinking about using a dual woofer config instead of a single 8" like in the Orion. I like the idea of two woofers so you get a little more surface area and roughly twice the thermal capacity. The problem I'm having now is whether to use dual 7", dual 8", or a single 8" Dayton Reference. I asked Monte why he chose to do a TMM and he said so he could have the tweeter at ear height, which makes sense. I will be using the new Dayton Reference RS28 tweeters, and using a crossover point somewhere between 1200-1500hz.

If I do decide to go with dual woofers, I'll probably go with an MTM config, offsetting the tweeter a little so I can get the woofers closer together, limiting their CtC spacing.

What are your thoughts? Any and all input is GREATLY appreciated!

Also, another Orion clone with dual Seas Excel W22 8" woofers:

http://www.doddsy.net/steve6_014.htm
 
I'd like the woofers to work as little as possible, so I will be going with dual 12 inch High Fidelity Dayton RS sub.

If you really want very little movement, you'd be better off looking at 15" or 18" drivers, the surface diameter of such size drivers(esp 18") is much greater than that of a 12".

I recently asked SL why he used 12", when something like an 18" would most likely perform better for around the same price. He said that basically a 18" didn't fit in with the aesthetics he was going for, which is more than fair, he has to sell the speakers after all.

Nothing exceeds like SD.

What are your thoughts? Any and all input is GREATLY appreciated!

With a bit of luck a 15"/18" config in a H frame should be able to make it up to 200hz or so, which should be high enough for a single 8" not to be straining too much.

If you can do it, i'd stick with the single midrange, less drivers=less problems.

I will be sticking with all Dayton drivers and am "stuck" at the moment.

Um, have you bought them already?. If so, the above might have been a great waste of time :dead:
 
Like Siegfried, I too have an aesthetics goal I need to maintain. These will look like the Orions, only they'll have dual 12s, which will give me about 60% more displacement than the Orions, which should be plenty. To keep up with that amount of low-end I was considering going with the dual woofer configuration, which will provide me with better dynamics and reduced distortion.

I'm not "stuck" with Dayton drivers. I said I was "stuck" as in which woofer configuration to go with. For the money, in my opinion, nothing can compare to the Dayton RS series.

Now, if I could only figure out which driver config to go with... :D

Thanks for your comments. Much appreciated.
 
Like Siegfried, I too have an aesthetics goal I need to maintain. These will look like the Orions, only they'll have dual 12s, which will give me about 60% more displacement than the Orions, which should be plenty

If it was me, aesthetically I'd rather go for one midrange and bigger drivers in the h/w/whatever frame, it's nearer the floor and doesn't garner as much attention as the main panel.

Are you set on having dual midrange, is it possible to sway you.

:devilr:

I'm not "stuck" with Dayton drivers. I said I was "stuck" as in which woofer configuration to go with. For the money, in my opinion, nothing can compare to the Dayton RS series.

Eminence Sigma Pro's are quite cheap at Parts Express, I guess around $120-145(they don't display their price), their appeal obviously depends on the price of the Daytons.

Daytons win aesthetically over the bigger driver(although it's only 6 inches ;) ), but I'd be very suprised if they could provide the same high spl/low distortion combo as the Eminence.

All depends on your needs/wants and what your willing to accommodate, elaborate a bit :)
 
My goals are a speaker that resemble the Orions, sound very similar to the Orions, but do not cost nearly what an Orion does. I will be using the Behringer DCX2496 and may use the DEQ2496 for active duties.

I am 100% sold on the dual Dayton RS High Fidelity 12s, two per cabinet, in an H frame, like the Orions. The only problem I am having is deciding between a single RS225 (8"), dual RS180s (7"), or dual RS225s. I'm looking for input on whether or not having such large drivers in an MTM would be a bad thing, seeing as how they're center-to-center distance will be 10 inches, or a little larger and the associated lobing that comes with large diameter midranges. Stepping down to the RS180s in an MTM I will be losing almost half the Sd, but I will be getting a tighter center-to-center, roughly 2 inches tighter. I will, however, gain thermal capacity over a single RS225 and have lower distortion.

Again, thanks for the comments and they're all appreciated! Anyone else, please chime in! :D
 
Mazeroth,

Have you considered the baffle size for the midrange/tweeter? If the baffle is large enough you should be able to get away with a tweeter and a single 7" midrange.. Although in the dayton RS series I think the 5" would make a better pure midrange than the 7" or 8" versions..

--Chris
 
Having read Linkwitzlab.com's description of the design of the Orion, it seems that the woofer to mid crossover is set at 120 hz due to the onset of cavity resonance of the H frame. I would say that a slightly wider cabinet with shallower H walls would allow you to raise the crossover frequency enough to get quite high SPL out of the single 8" Dayton woofer.

Since a dipole speaker tends to be limited much more by Xmax than by power handling, I wouldn't worry about getting extra thermal handling from two drivers. The MTM with 8" drivers might be unnecessary.

What I would worry about, however, is the energy storage and breakup that occurs at a lower frequency for the RS225 than the RS180. The Modula design by Jon Marsh uses the RS180 and RS28A in an MTM configuration, and seems to be a well executed design that considers dispersion, lobing, and power response. If you used this configuration on top and managed to get the crossover to the 12" drivers up over 150 hz, I think you could get some very good results and have some impressive dynamics.
 
It sounds a lot more like you should clone the Phoenix main panel using the RS drivers and stick that atop your H-frame. The Orion isn't an MTM. The Phoenix is. If the design is executed properly, you will have terrific sound and prodigious output. Good luck.

Cheers,

AJ

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Hi Chris,

Sorry about the tardiness. I did get your email, but have been so busy.

I think that if you use the RS28A, then you should consider the RS180's in a dipole configuration. The RS225's should be crossed around 1.2 to 1.4k d/t the energy storage issues(i.e. the dip) that's present around 1.6k. With my RS225 two way, I've crossed at 1.2k and this dip is >30dB down after the Cauer filter.

It takes some guts to get an xover to 1.2k. Not all the RS28A's can go quite this low. Using an xover below 1.5k probably means individually testing the tweeters for their distortion patterns.

While I think that the RS28A has a more advanced design, the Seas 27TDFC and TBFC/G seem to have a bit more reliable low end brute force excursion consistently.

Using the RS180 allows you to push up the xover point just a little bit, to 1.5-1.8k and gives you a bit more freedom.

I personally like the idea of a single RS225 mated to a Seas 27TBFC/G and a couple of RS10's, but I'd like to get my hands on some more TBFC/G's before I committed to that route.

Sometimes it's hard to answer these questions until you build it and test it. So, the safe bet is dual 7"s.

hope that helps

mark k

RS 225 two way
 
It takes some guts to get an xover to 1.2k

No, it takes a wave guide to XO @ 1.2k, or lower;) .
The RS and SEAS are both robust enough to handle it. The DCX can take care of the rest (EQ). The sample to sample difference in performance of the RS is rather worrisome (for this type of app) however.

Cheers,

AJ


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