LE15A/375/075 Box Design

[Val]

Jeez, $144. Time to clean some up around here.

Why'm I sittin' here lookin' at these dusty things...?

Sold for $210!

[Zilch]

[GordonW]

I've thought about putting the ports up top on the front. I'd like to avoid that if I can as I'm thinking I will only cover the LE15A with a grill. I like looking at the 075 and 375/L91 and will leave them exposed.

I like the idea of back mounting the ports. If I do so, how far should the cab be kept from the wall? Now that space is not an issue is it better to go with one 4" port rather than two 3"?

Hmmm. 3/4" mdf is easier to get and work with. Is it overkill to go w/1"?

Shouldn't be a real issue, two ports vs. 1. Though, IME, multiple small ports have less problem with "port chuff" noise, than one large port of the same area. Something about flow velocity differentials across an area, AFAIK...

And, with an LE15, a rear-mounted port might help "augment" the deepest bass. Might help extend the effective in-room f3 a few Hz lower. Be prepared to use a slightly longer port than calculated, though...

Regards,
Gordon.


Regards,
Gordon.

[Val]

"port chuff" noise

Gordon...that cracked me up...port chuff! Very descriptive. I'll take your advice. I don't want no stinking port chuff in MY living room! It's bad enuf to have to listen to the cat hurk up the occasional fur ball.

I really like the design now. It might even be final. Time to buy materials. I appreciate all the comments. I'll take pictures of the build.

[GordonW]

If you really want to potentially "amp up" the low-bass output of the port, put 'em near the bottom of the back panel. Closer they are to the wall/floor junction, the more "acoustic gain" the ports will get. With the f3 of these being rather high (compared to typical 'modern' speakers), it might help "fatten them up" a bit. However, as I mentioned before, do be prepared to try longer ports than predicted... I've wound up cheating the port frequency lower than the box program recommended, just to "balance out" things, so that I didn't wind up with a surplus of "upper bass" (ie, between 50-100 Hz)...

Regards,
Gordon.

[Val]

I've built the first of the two boxes described in this thread. I am very happy with the way it sounds. Waiting for the insulation to come so I can finish it up. I'm on to details like feet. I'd like to ask for opinions on speaker spikes. Are they worth the trouble and expense? My boxes are about 4cu ft and weigh a ton. They will eventually sit on hardwood floor in my living room.

[yggdrasil]

I would not go for spikes. Spikes can make serious damage to your floor and anything else it comes in contact with when mounted on such heavy speakers.

[edgewound]

I'm with Johnny on that one, Val. If you must decouple from the floor, you could use rubber feet or Anti-vibration leveling mounts from Sorbothane....since your cabinets weigh a ton.

[mdlupke]

Congrats on your project, Val! Look forward to seeing images. What are your ports made of, and how are they attached? If they were mounted with a plate and screws to the outside of the speaker cabinet, you could experiment with tuning by sliding in pipes of different lengths (all the same diameter) without having to disassemble the box.

MDLupke

[grumpy]

nice project! might want to consider building a pair of short plinths to set them on...
it would let you play with the idea of leaning the fronts back slightly so those
bullets aren't pointed at your knees Furniture feet under the plinth could help keep
the hardwood floor from getting damaged. Pics would be nice if possible.

Happy New Year!

-grumpy

[Zilch]

Is the purpose of spikes to couple to, or de-couple from, the floor?

[grumpy]

Other than epoxying it to the floor, I can't imagine a method more likely to couple
a horizontally vibrating structure to a floor In the case of a hardwood floor
(if not over a concrete slab), this can cause interesting sympathetic vibrations
...and not necessarily from your significant other. One of those things that are very
installation dependent...

[Val]

All the reading I've done on spikes has been from people selling them and so is biased. If I understand correctly they are to anchor the speaker firmly to the floor so the speaker box has a firm footing to "push" against. I appreciate the comments and plan to pass on the spikes. I've yet to weigh the boxes but think they will be well over 100lbs.

Grumpy, what's a plinth?

I'm using 3" abs for ports from Home Depot. They are not permanently anchored yet. Once I get them tuned I'm planning to glue them in place. Currenty they force fit into 3 1/4" holes in the back that are not routed all the way thru. I'll include pics soon. It would have been a good idea mount as mdlupke suggests...oh well.

I apprecate the comments. Pics to follow.

[jbl4ever]

Hello Val, try some run of the mill hockey pucks. Available at most sporting goods stores. A bag of 12 about $10. Counter bore 1 side to accept a 1/4x20 Tnut about 1/2'' deep. Using a C-clamp to set them. These seem to work good for me on granite floors

[grumpy]

somehow, I knew that would bite me... just a base to set something on,
like under an architectural column (in this case, picture a box with no top
or bottom that's slightly lower in the back if you find angling the speakers
back helps). I like how they look when a bit smaller than the cabinet
dimensions.


-grumpy.