Maxwedge, thanks for the encouragement! I'll need it to get through all the sanding!
I picked up the baltic birch plywood today and plan to start the cabinets over the weekend. Also, I ordered some figured cherry veneer that should come next week.
Maxwedge, thanks for the encouragement! I'll need it to get through all the sanding!
I picked up the baltic birch plywood today and plan to start the cabinets over the weekend. Also, I ordered some figured cherry veneer that should come next week.
I've been unable to work on the speakers for a little while, but got a couple hours in today. I'm just posting a couple pictures taken this morning of the components. I had the K130's out to check the layout, so that's why they are in the pictures. I'm setting up to cut the lock-miter joints. Once that's done, it should go fairly quick. The roll in the background is the figured cherry veneer. I'm planning to use Heat lock on the veneer. Has anyone used this product?
Looks very nice indeed.
If you havn't cut holes for the ports yet. Placing them close to the floor will make the boxes go a bit lower.
You can also use hornresp to simulate driver placement in box, if you place the ports at the bottom. I did that for a box I am building, and the best result was when placing the driver in the middle of the baffle.
Hi More10,
The baffle is not cut yet. It was just one of those weekends that I should have skipped trying to make progress on my project.
I downloaded Hornresp, but didn't get far with it either.
If I understand you correctly, moving the ports closer to the floor may improve low end. Is this boundary loading? I remember reading that you can get boundary loading if the port is no more than 1/4 the length of the sound wave at the port's tuned frequency from the boundary (wall/floor/ceiling) and in an un-interupted plane abutting the boundary. A 40 hz wave is 28.15 ft so the critical distance should be 7 ft. (speed of sound 1126/40 = 28.15/4 = 7.3) But if it affects frequencies above tuning the distance would be smaller. At 100 hz the distance drops to 2.8 ft.
I remember wondering about this when I looked at the ports of the JBl 4647. The ports are pretty far from the floor.
I'm booked up for the next couple of weeks (no woodworking), so I'll have time to ponder this before cutting any holes.
Your input is appreciated.
This is not boundary loading. If you are very close to the floor the floor will act as a continuation of the port. Speakers with a slits port at the floor is using this.
Boundary loading is something different. One problem with winisd is that it doesn't calculate the effect of boundary loading. However Hornresp will. Ill pm you some hornresp pictures when I get back from work tonight.
I know some folded horns used the walls to extend the horn, so I'm very interested in what you are saying about ports. I look forward to hearing from you.
I just wanted to post some updated pictures of the Smith horns. Hope this is helpful to someone else wanting to build a set. The rug is on my back patio, so please don't think I keep a messy house.
Those horns are beautiful! What is the cutoff frequency?
Nice work man!
Cutoff should be close to 800hz. The size, angles of the horn are based on the JBL 2397, which is 800hz. The shape of the mouth is different, as it doesn't flare vertically. I used the straight design from the original "Smith Horn." That horn did have a narrower horizontal projection and was supposed to cutoff at 750hz. I'm not fully satisfied with my calculations, but I'm pretty sure its close to 800hz. Its got a 130 degree horizontal dispersion and is 1 inch on the inside from top to bottom. Radius is 14 3/8 inches (after sanding ). The throat of the driver actually sits 7/8 inch behind the center of the radius.
Thanks for the encouragement from everyone.
Well, after playing with hornresp for some time, I couldn't come up with an improvement to the porting. Actually, I just wasn't confident my skills with it. So, I moved forward with the plan I had.
Heat lock works well for the veneer. I've done the baffles and will do the remaining work once the cabinets are glued up.
I'm using 4" ABS for the ports. The front to back brace will be 2X stock rather than the 1X in the picture. The corner bracing is hardwood, so its smaller. Originally, the joints were to be lock mitered, but I got a lot of tear out. So, I decided to mortise the panels. Here's pictures of the parts assembled for a dry fit. I still need to drill for the screws and route the back for the x-overs. Progress!
I wanted to post pictures of the final result, so here they are. I tried the 2225's, but found the mids from the K130's were just too nice to let go of. So, the K130's are in them. I've also decided to add a sub and bought a Yamaha home theater unit with a built in crossover for the sub. I just need to build the sub now.
Response is very good, but starts rolling off around 50 hz. I'm surprised at how much is there, given the modeling in WinISD. Vocals and acoustic instruments sound awesome! Very clear and full!
On a side note, my daughter's high school drama class received a gift of a concert sound reinforcement system from an estate. I've been asked to help sort out what's good and to upgrade the drama departments sound system. There's a lot of JBL, Altec, EV and Gauss components. Its been in storage for 15 years and some stuff is junk, but there's a lot of good stuff. We'll probably sell off most of it, as its just too much for the intended room. I'll start another thread when we get going.
Sorry it took so long to post, I actually just got the speaker grills done.
Very nicely done!!
My only thought would be that unless you're squatting on the floor when listening, you might want the 076 up a bit higher off the floor, but I'm not there to hear them . . . and I've never owned the cat's eyes.
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
Very nice build!
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