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3 Eminence 3015LF bass modules

22K views 56 replies 10 participants last post by  atledreier 
#1 · (Edited)
Thought I'd start a new thread since the design is more or less finalized now.

I'm making three bassmodules for my LCR channels. Hoping to cover 40-300 or thereabouts.

Ricci came up with an enclosure for the drivers, and they model beautifully for my use:
original thread

Slot port, 46w x 8h x 21.6cm





They will be driven by Behringer EP4000, they get one channel each. I have three amps. One channel for my Klipsh KL-650THX mains and one for the Emmy for each LCR. EQ and crossover duties by a Behringer DCX2496.

Hoping to get some more midbass punch, and offload my LLT sonotubes a little. Maybe I won't even need the LLTs for music. (I'll still use them, most likely). The bassmodules have a potentioal 132dB at 500W each, so I'm hoping the Klipsch mains will keep up.

Ordered the drivers from Parts Express, but since shipping from the states is so slow it'll be a while before I get started. I'll get the amps and DCX before that, so I can start optimizing the mains while I wait! :T
 
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#7 ·
They will never be visible, I'm putting them behind my screen, so looks is no concern. But doing dual material baffle is sure to have a benefit to break up resonance. Good call.

So if i want to flush mount the driver to the baffle I need a third layer, right?
 
#8 ·
No expert here, but I don't think three layers is necessary, particularly if it is ¾"/19mm material and well braced. I really want to hear your opinion(and REW) once you complete it. I have a similar setup, but the 12" drivers won't play nice higher up like the eminence.
 
#9 ·
I'm planning on using 22mm MDF for the inner layer and braces.

The slot port will form part of the brace, I think. Haven't really thought about the box design yet, just the overall dimensions, primarily to minimize material waste.
 
#12 · (Edited)
Yeah, I thought about that too. I hope some of the bigshots around here will chime in on the design, though. I am concerned about the opening area of the brace being large enough to not affect tuning.

 
#13 ·
Right. What is the internal dimensions of your sketchup?

I'd not do the bracing with the port like that. I'd be concerned about it affecting the port loading. Adjust your port area so that the port is the full width of the enclosure and that will naturally tie into the walls for bracing. Make sure that you leave at least 8" or so from the rear of the port to the back wall. For best results leave about 8" of clearance around the port end top to bottom to. You can add shelf braces above and below to tie the back panel into the sides and front if you want.
 
#14 ·
The internal dimensions is 60cm wide, by 40 deep, and 80 tall, which equals 192liters. Subtracting post and driver/bracing, and we're not far from the modelled 184 liters.

I can make it a little deeper maybe, to give the port some breathing space.

I'll see what I can come up with.
What port dimensions do I need to go 55cm wide for the port?
 
#16 ·
Keep forgetting how BIG 15" woofers are! :D

These lightweight drivers will be very exciting to test in my theater. The magnet is very small, but apparently very powerful neondium, so it's all right, I think. I was amazed how light they were, though. :) Nothing like the Soundsplinter beasts.

Only got two today, the third is lost in the mail somewhere. according to tracking it was shipped overseas via Paris to Oslo, and the sent back to the states?!? It'll get here eventually, I'll start making the enclosures this weekend. Haven't got the amps or the DSP yet either, so it's all right.



 
#21 ·
Yes, I thought about the brace below the port. I'll just add another one like the top, withouth the cut for the driver.

Does the driver spacing and port placement seem ok? It's about 11" from the bottom to the port, and about 11" from the back panel to the port. Would you place the brace midway between the port and the bottom, or further up?

What about a narrow strip of material from the upper port panel to the back panel? That would be cloce to center of the back panel, and a 2" strip shouldn't interfere with port loading? It would transfer a lot of stress from the back panel to the double front baffle...
 
#22 ·
Driver and port placement are fine, whatever looks good to you.
Would you place the brace midway between the port and the bottom, or further up?
What about a narrow strip of material from the upper port panel to the back panel?
A centered vertical panel from the bottom of the port to the bottom of the cabinet will give you all the support you need. (excuse my Paint abilities!)

Furniture Table Shelf Line Parallel


 
#23 ·
That's pretty clever! I have already got the materials cut for the enclosures, with a horisontal brace, but I can cut that to fit like you drew, that looks like it will do the job.

I've been recommended to put som damping material in the bottom. Was thinking of using a 4" Rockwool acoustic panel cut to fit. Any more damping I need?
 
#25 · (Edited)
Well, I built two of the boxes so far. After initial setup and EQ I'm happy with them. Not a mind-blowing change so far, but I'll let them settle a bit and try out some different crossovers and whatnot. I also need to build the last one for the center speaker.

I must say the entire system sound incredibly effortless now, though. Very pleasing. I've EQ'd for a flat response, so they are not thumping unless the music calls for it, but then the really can kick. Been playing music for a few hours now averaging around 100dB with peaks a bit higher, and the amps are still cool to the touch.

I need a little input on highpass filter, though. The enclosure design rely on a 35-40Hz highpass. Initially I ran them with a 24db/okt Bessel highpass at 40Hz. After I made sure everything was working and hooked up right I added the subs. With the processor bass management I get 12dB/oct highpass. That didn't really sound right, so I removed the 24dB/oct Bessel highpass and used just the processor's 2nd order HP. Is this steep enough for this design to be safe at 'any' level?

Edit: I have some pictures of the build process, they are too large for the gallery here. Need ro scale them.

Edit2: Made it easy on myself, made an online album: ALBUM
 
#26 ·
Looks well built- should finish nicely :T I never crossed mine higher as I initially intended since I went with sub drivers instead of what you've got. My lower end is as you say- effortless, but I am really curious how everything would sound since I only have small bookshelves on top (5.25" mid).

Those Eminence drivers look like they handle power really well; I would think you're plenty good with the 12dB highpass, except perhaps for excursion. If you use the DSP's crossover for that channel, you'll need to disable your receiver's crossover to it for sure. But you should see/hear the limit of xmax and I seriously doubt you'll have a problem in the mid-bass region. I bet heavy bass guitar really shines on these.
 
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