[i4gotmyid]

I am just starting to look at open baffles and I have the following parts:
4x AE Speakers TD15m
Fountek NeoPro 5i
I was using them in a massive 3 way with a midrange which I am not too fond of, so it will remain un-named. 

I was going to make a simple JE LAbs OB, using a TD15m and a fountek 5i, and run the td15m full range until it drops off and add the fountek as a helper tweeter, but then i would have 2 leftover drivers...

Now I know these arent the best open baffle bass candidtates, but I started contemplating using two td15m's and one fountek 5i and using the second woofer as a mid-bass helper from where the first would roll off.  Could I substitute a 2nd woofer for a smaller baffle? Say 20" and use the 2nd woofer around 228hz (roll off of the 20" baffle)? How low would that get me?  I tried modeling it in basta, but got wierd results, of which i am not sure how to interpret.  Does the baffle of 20" dictate the bass repsonse of both woofers as it does for one?  Or does the 2nd woofer add +3db (+ or - floor coupling varience) but falls in the same 6db slope just adding 3 db (assuming no eq on the woofers)?

So before i start cutting I guess, should I use a 42" x 20" baffle with two woofers? or keep to the original plan of the JE Labs?

[rick57]

I'm not answering your question, however this is relevant to your plan:

The fountek's minimum recommended crossover frequency is 1.5 KHz.

I have TD15Ms, and was thinking of doing something similar with them, hence my interest.
I've read most of what been said about them . .  the TD15M is very flat & extended, and might normally be crossed as high as 1500.

I'm no expert, however I would have thought that due to the greater directivity of drivers when mounting in a dipole, would mean by 1500 Hz it would beam too much.

In a dipole, I suggest a max for the TD15M of c 700 - 900 Hz.

[JohnR]

Not answering the question either... but what was the midrange? Just really curious... BTW have you tried the configuration you suggest in the existing box (i.e. TD15M plus ribbon)?

[i4gotmyid]

I have been messing around with the crossover/full range options in the box for my three-way...running the td15m fullrange and the fountek around 3k-3.5k 1st order crossover and it seems to work great...although as far as beaming is concerned I was sitting in front of my speaker for a majority while working on it...and just messing around last night, dropping the cross to around 1.5k-2k and sitting 60 degree triangle didnt seem to hurt/help beaming vs 3k-3.5k

As for beaming/directivity...is there a difference btw running a 15" full range on an open baffle and what I am doing?  I assumed that with the tilt in the JE LAbs baffle, plus toe-in would resolve this...

[JoshK]

I don't think OB versus box is going to make a big difference as far as beaming since you are above the baffle step.   I haven't modeled it but I suspect the TD15M will rolloff quite high on OB.  You'll need a lot of EQ to reach low. 

You might consider selling or trading your extra pair of TD15Ms and get a pair of Dipole15s instead for down low.  I have an extra pair of TD15Xs I'd trade with you for the 15Ms but that wouldn't work much better OB.

[i4gotmyid]

while the trade sounds interesting, i'm just looking for a high sensitive open baffle, which is why i'm using the 15m's...it doesnt need to get low, just to 80ish, then i can get my 40hz horns taking over the low end (course i'm still working on them)

[scorpion]

I think I would go with 2 AE15Ms on the 42 x 20 " baffle. You will win 6 dBs connecting in parallel. I have simulated this in MJKs Worksheet (courtesy MJK). Lowest AE15 is 8" up and the next one 23" up with the centres. Lowest AE15M is crossed at 400 Hz (seemed a little better than lower) 12 dB/octav Linkwitz-Riley. The upper is fullrange, no crossover can be applied in this simulation, but it looks like you can go to 1500 Hz with no problem. Efficiency will not really match the Neo5i but overall it will be better than one element in the JE Labs type.



/Erling

[i4gotmyid]

thanks i appreciate the graph and the info, i'll work that and see how it looks in real life.

[Angaria]

I've got a pair of dipole15's that play up to a point where a variety of horns can take over (~1-1.5kHz), but they don't have the sensitivity of the 15M.  What kind of amplification are you using?

Like everyone else, if you want to sell of a pair of the 15m's, I'm listening