Come watch a noob try to not screw up an Omni 15 TallBoy!

[CaseFAceMcGee]

Starting the process of disassembling and reassembling the crossover. Here's a better picture of it:

http://i301.photobucket.com/albums/nn68 ... G_2279.jpg

[Harley]

You're going to do them on 3 different boards, right?

Coils must face different planes and directions, the further apart the better.

[CaseFAceMcGee]

I removed and reassembled the high-pass filter off the board, with the coils as far apart as the leads allowed from the board and each other, with their axes perpendicular and not pointing towards each other or in the path of the coils still on the board. I checked the wiring before, during, and after assembly for accuracy. Still no change in the performance.

I have a wedding tomorrow night where I have to use this cab, so I removed the tweeter components and rewired the midrange components accordingly... assuming it makes any difference at all with my mess of a setup.

Next week I'm going to try a ground-up rewire, with all wires, coils, everything as isolated as possible, and if that doesn't make a difference I'm probably going to say screw it and order a complete premade crossover from Leland. I've wasted enough time and energy with this, I'm done dealing with it.

[Harley]

I'm lucky. I have a son who is an Avionics Tech and he checks my crossovers each time I build them. Plus he has some clever soldering tips.

But yes, if I was in the USA, I'd not hesitate to use Leland's crossovers/filters and be done with it. I think he sells them too cheap in actual fact!

[CaseFAceMcGee]

One of my good friends back at school is an Engineering Physics major, pretty far along in his degree progress. He's going to be checking all of my current crossover's components to check if any are bad in some way, as well as checking my wiring. If it can be made to work, it'll just sit around until I can make another box. The university-owned bass amp is crap - maybe I could get them to cover costs for the components and I can build the box for them.

[Bill Fitzmaurice]

Also be sure that what you're hearing isn't the amp clipping. Be sure you're using the master volume to control your level, not the gain.

[wounded horse]

I like to refer to this

[CaseFAceMcGee]

The cab performed admirably at the wedding gig on Saturday. During our soundcheck/rehearsal with the singer, I had my volume knob set at a conservative level - about 9:00. A guest at the wedding, who is an experienced sound guy at the university, said that during the soundcheck the bass was a little heavy in the mix and I should turn down a bit

Today I hooked up the amp to my computer's battery backup, as it can display wattage used. With the amp warmed up so the fan was running, it pulled 30 watts with no output volume. The display is slow to update, so it wasn't really possible to find peak wattage for transients, but I was getting readings of over 300 watts easily with the volume knob set just over 11:00 so it wouldn't surprise me if the amp is clipping a bit and that is the cause of this infernal noise. I didn't think that the head would be putting out so much power with the gain set at about 10:00 and the volume at under half... I'll be looking into how to figure out if the head is clipping for sure and how to protect my stuff from damage due to that.

I tried using a DMM Friday to measure voltage at the woofers and mid driver to determine how much power they were getting, but it didn't seem right - at the same levels as above, I was getting maximum readings of 2-2.5 volts at each woofer, which didn't seem right at all for the amount of noise it was producing, and that doesn't match up with the wattage readings from today. I know my improvised wattmeter is showing input power to the amp and not output power to the cab, but it's a hell of a lot more accurate than my DMM wants to be.

I've checked my crossover so many times without any signs of incorrectness, and I tested every part of the tweeter's crossover and each cap showed a resistance of infinity after a few seconds like I read they should, so I don't think anything is wrong with the crossover - I think I'll reassemble it with all of this input in mind and see how well it performs in more groups.

I'm also considering the installation of L-Pads for the tweeter and the mid driver. I know it should work fine with the tweeter, but I don't think I've seen anyone use it for the mid driver... any thoughts on how well that would work? Parts Express has 100watt L-Pads and a 2-unit faceplate labeled for mid and high, so it can be made to look nice... I just want to know if it will perform well also.

[Bill Fitzmaurice]

A 100w LPad will handle the midrange. 50 is plenty for the tweeter. I'd also work with the amp EQ. This cab puts out lows better than any commercial cab, so you should be using little or even no low EQ boost. Doing so eats up power like mad, and could be the source of the clipping. If the amp's clipping LPads won't help.

[CaseFAceMcGee]

Thanks Bill. I've been using the EQ flat so far, but I had the vintage loudspeaker emulator knob up at about half - that may be what's causing it to push so much power.

The rest of this week, I hope to get the crossover back together and do some more testing, make the speaker grill cover, and get another coat of DuraTex on the cab. I also need to figure out a way to stop these handles from rattling. I have the recessed spring-loaded handles from Leland at SpeakerHardware, and they buzz like crazy on E and B. I had installed the gasket around the lip, and I put on some more gasket tape on the back of the recessed part, but that wasn't enough. I even put gasket tape between the handle and the frame, but it didn't stop the rattle. For the gig I taped the handle down with electrical tape and that stopped the rattle, but that's not very convenient, not to mention how unprofessional it looks to have to tape up the cab for it to sound good.

[Bill Fitzmaurice]

I have the recessed spring-loaded handles from Leland at SpeakerHardware, and they buzz like crazy on E and B.

If possible the cab panels under them or very close to them should be connected with a brace.

[LelandCrooks]

Never had it happen with Penn handles. Long ago I used a cheaper handle that buzzed, switched to Penn's because they were so much better and did not buzz. I put a piece of felt like you use under chair legs right at the hinge joint on them and it cured it.

[CaseFAceMcGee]

I'll give that a try. My other idea is to squirt a bit of silicone into the joint and move the handle up and down as it sets, so it would act kind of like a bushing instead of gluing the handle in place.

[CaseFAceMcGee]

Cloth speaker grilles are tough to do... and really time-consuming... but I'm really glad I made one, it looks sharp:



I got the cloth as straight and tight as I was able to, and when I test-fitted it, I discovered that the middle area was tightened enough to pull the boards in a bunch. To try to combat this, I put in a support strut across the middle, at the same height as the board between the two woofers. This didn't fix the issue entirely, but it helped a lot.

I'm going to go ahead and call this build finished. There's a few more odds and ends, like the accent paint I want to apply and the handle rattle, but I know I'll be putzing with things here and there for months or years - might as well call the old girl done. I'll put up a review and more pictures after the block party gig I have in three weeks. I'll also try to post fixes that I've found to work well with the little issues that I've come across during the build.

Thanks to everyone who helped me get this build together and put up with my enormous lack of experience

[Dan30]

Wow man that looks mega sharp!