Finalizing box volume for SS8565-01s, does this look about right ?

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I am finally getting down to finishing my speaker tower. Its now down to final two cabinets, for a pair of ss8565-01s. I have been playing with WinISD and came up with 60 Liter sealed for a Q=0.6 and F3 of 65hz which is a no-no. Vented 60L tuned to 30hz with round 4" by 14.5" inch port (I would like to use the flared AeroPorts) has F3 of somewhere around 40-45hz which is much better.

Does this look about right ? I am going to a cabinet maker this weekend for the final cuts, so then there is no turning back :magnify:
 
What T-S specs are you using Jean? As you know I have used one of these in my project, and my numbers are fairly different. My sealed unit goes lower in a 55 litre enclosure (f3 = 40 Hz).

Also, what alignment and Ql are you using for the ported simulations?

Mick
 
Hello Mick,

I realized that I was using wrong parameters. Looks like a sealed enclosure of about 60 liter is a good choice for F3 close to 40hz. I hope it will be enough to fill an average size living room with good quality bottom end. Ported enclosures look too big, and for music 40hz before room gain should be fine (crossing my fingers here).

This turns into a fairly compact 30" by 12" by 15" cabinet, and will bring my two ways to just about ear level when sitting.

Since I have not purchased them yet, I still have time to figure out if I should go with 8565-00 or 8565-01. Do you have anything to add ?

Jean.
 
Hi Jean

I decided to go for the -01 version because it gave a much smaller cabinet than the other version. The disadvantage is that the f3 for the 01 version is slightly higher (40 Hz) than the 00 version, which should give you around 35 Hz, but that's not much difference. I am toying with the idea of using a Linkwitz transform circuit to extend the bass lower, as I already have an active XO, and so it's not too much work to do. I suspect that for me there's not too much below 40 Hz that will be of interest.

I've been listening to the almost finished speakers for a week or so now, and initial impressions are good. I don't really want to rave about this particular driver, as i can't really compare it with anything else, so any statements about how great it is may be meaningless.

Mick
 
Mick,

Thanks for the input, appreciate it! My cabinets should be done by next week, I went ahead with the 60 liter sealed size and will see if polyfill helps. They are going to be 30" - 31.5" high, and will bring my current two ways up a bit higher than current speaker stands. What did you do with bracing ? I am doing one verical brace behind the driver, it will "T" with the horizontal brace down the cabinet .

Jean.
 
Jean

If you have a look at my recent post "cross brace not working" you'll see some photos of the bracing that I used.

In a nutshell, I put the driver at the top of the cabinet, which I'm not sure was the best thing now (more about that below), and used a shelf brace (which you can see in the photo that was just at the level of the bottom of the driver frame (ie about 250mm from the top). Then I added another brace below the shelf brace to connect the two large opposite side panels together, as they seemed to ring fairly low. I haven't measured the resultant vibrations, as I don't have the ability to do this easily at the moment.

The reason that I'm not sure whether putting the driver near the top was the best thing to do is that I am suffering from a floor bounce dip at 200 Hz, which would be able to be reduced if the driver were closer to the floor. See my post on this recently. I'm going to do a bit more investigation into solutions for this, and will update that other post when done. So it may be best not to do the driver cutout for the moment, if you can. Or maybe you can advise me on this :confused:
.
Mick
 
Kanga,

Found your post with pictures on bracing in your cabinets. I am doing something similar. My first brace is going to be vertical behind the woofer and it will extend about 1/2" way down the cabinet. Second brace is horizontal and it will form a "T" section with the first brace where they meet.

I will have my cabs done by this coming up friday, and my woofer center will be about 24" from the floor. Did you measure the floor bounce somehow or calculate it ?

What did you do about internal damping of the walls in the cabinet ? I am thinking about lining the back and maybe sides with open cell foam and stuffing the cabinet with polyfill material.

Jean.

P.S. is your speaker a 3 way or 2.5 ?
 
Hi Jean

You bracing sounds like mine upside-down, but I can't see any problems with it.

I measured floor bounce dip using a sound meter and test CD.

I didn't damp the inside walls, as I think that it is very difficult to damp 25mm walls by just sticking on damping pads or bitumen. They are very stiff, and without very thick damping layers I don't much damping would result. Lots of people seem to have different thoughts on this one though. I will stuff the cabinet with fibreglass to damp internal sound waves from the driver.

I am just about to post a project report on the speaker - have a look for more info and photos.

Mick
 
Mick,

I ordered couple bags of polyfill along with the drivers. My 8565-01 pair are due this friday and cabinets will be done this thursday or friday. Can't wait to start playing with them. I will use my behringer cx3400 for now between the two ways and the bass drivers. I will most likely switch back to passive later, and use 4 channels to power the speakers . Two for mids and highs and two for bass.

Jean.
 
Hey Guys,

I'm working on a pair of cabs, 120L with 2x 8565-01's per cab. The walls are 40mm thick mdf. I added some bitumen pads(they have 10mm of closed cell foam aswell) over all the inside walls, and now if I put my head in the box and shout a bit, I hear a lot less reflection than before I added the stuff. This before I stuff the boxes (sealed)

Also a lot less high freq stuff gets inside the box with these pads... (the radio at work sounds like a "sub" channel with your head in the box)

Don't know if that helps but.....



Rob
 
Can we have a photo Rob - of you with your head inside the enclosure listening to the radio that is :rolleyes:

Was the aim of the extra damping to reduce wall vibrations or to absorb the woofer acoustic backwave?

Jean - you're a fast worker. It took me about 4 months to "finish" mine, but I did cut the wood to size myself I suppose. What XO points are you going to use?

I'm going to try to measure the Qt of the speakers today, so that I can seem what difference the stuffing makes.

Mick
 
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