[Kevin Haskins]

Wiggins was over visiting today and we worked on a dipole design with the EX-6.5.    Its sounding very promising at this point but I'm anxiously awaiting a couple DPL-10s to turn it into a full range solution.   

An easy to build 12" x 48" baffle with drivers mounted is used.    Using the BG Neo3PDR because it becomes a dipole simply by removing the rear cup.     Having dipole operation and the narrowing off-axis response in the midrange is helpful for limiting early reflections where they are most harmful.   



First shot at the crossover.   Not bad.... the little dip centered at 1.6K & above voices it a little laid back.   I'll play with that some more.   Notice that phase in the 200-8K region.



Impedance curve.... nice and easy load.   No crazy phase angles and a minimum of 4.2 Ohms at 2.2K.

[klh]

Keep it coming!

[Kevin Haskins]

There.... I decreased the size of the pictures.    I posted them in haste last night before leaving for home.

[mcgsxr]

Everybody loves an OB with a small width, helps to keep the WAF high.

How much wider do you think it will get, when adding the woofers?  Or would you simply fold that section, and thus retain the effective visible width at 12 inches?

Thanks for sharing!

[Kevin Haskins]

Everybody loves an OB with a small width, helps to keep the WAF high.

How much wider do you think it will get, when adding the woofers?  Or would you simply fold that section, and thus retain the effective visible width at 12 inches?

Thanks for sharing!

The plan is to fold it and maintain a 12" width.    The effective width of the baffle folded, in combination with the floor is going to be significantly wider.   It should allow us to get to 30-35Hz with some real output using a pair of DPL-10s per side.   

The first version is going to be totally passive.   You only will need one amplifier to drive the entire system which keeps the system cost down and complexity low.    A pair of UcD400s should drive it easily and the total available excursion of the drivers will be the limiting factor in maximum SPL.   

[Won]

Very exciting!

If you're adding 2 10" woofers, do you still need both 6.5" midwoofers? Why MTMWW instead of just TMWW?

[Kevin Haskins]

Very exciting!

If you're adding 2 10" woofers, do you still need both 6.5" midwoofers? Why MTMWW instead of just TMWW?

Yes... you do for a couple reasons.   The 10"s are going to be hidden away under the 12" x 48" baffle in a folded baffle.   That is part of what gives us the bandwidth, the wide effective baffle.    Second, if we mounted the 10"s like the EX-6.5 then we would probably have response issues that would be difficult to deal with.   

Trust me, if I can simplify it I will.   I strongly believe the simplest solution is often the best.    Its just that sometimes complexity is needed.   

[klh]

I have a couple stupid questions...

Will you make a center channel? Or, put another way, can the MTM open baffle be placed sideways with a built in stand making the open baffle part 2' above the ground (or 1' above a short but wide rack)? The baffle height in the MTM region alone looks like should be at least 20" tall if vertical... that would be a difficult fit under a FP screen. Will the MTM go down to 80Hz?

[Kevin Haskins]

You could spin it and run it as an MTM.   The crossover is low but it would be a strange set-up for a center channel.   The dipoles tend to work best pulled out into the room with some space behind them for the rear wave.   I figure about 4' gives you enough delay between the first arrival wave & the second.    A center channel in most instances is going to be right up against a wall, not an idea setup for dipole use.   

I view the dipole as a 2-channel product.   You would be better off with a more traditional box design for HT use on the front/center/right where you don't have as much concern over wall spacing.   

In terms of LF output... I'd say we have reasonable output to 70Hz in-room as its designed, maybe lower.    I may raise it slightly depending on how the DPL-10 section works out.

[Won]

Yes... you do for a couple reasons.   The 10"s are going to be hidden away under the 12" x 48" baffle in a folded baffle.   That is part of what gives us the bandwidth, the wide effective baffle.    Second, if we mounted the 10"s like the EX-6.5 then we would probably have response issues that would be difficult to deal with.   

Trust me, if I can simplify it I will.   I strongly believe the simplest solution is often the best.    Its just that sometimes complexity is needed.   

Makes sense, but I wasn't wondering about the 10"s or their mounting...I was wondering why you needed both EX-6.5s. Or were you saying that you need both EX-6.5s to crossover low enough for the 10" woofers because of the folded baffle?

[Kevin Haskins]

I'll post more information when I get measurements of the actual drivers in the enclosure.   Until then, its just conjecture exactly where I'll crossover.   It depends on how high I can run the 10"s.   Then I'll probably look at some distortion measurements in an anechoic chamber to see where it makes the most sense from a distortion standpoint.   My guess is that it will be somewhere between 70-120hz.    I'd feel better using two of the EX-6.5 simply due to the demands that dipole use puts upon the bass sub-section.   

I won't be getting the DPL-10s until late October.    It won't be until sometime in November that I have them built and measured.

[klh]

Have you had a chance to work on these?

[Wind Chaser]

Using the BG Neo3PDR because it becomes a dipole simply by removing the rear cup.

Does anyone know if these can be fitted in place of the RAW 104.5?