Another OCD build

[Ludo]

Re: Another OCD build

Louis- I think I would have 'clamped' the driver instead of using screws in this case.
Just my 2c,
Wolf

Wolf,

Any pics to illustrate how that's done? I'm having a difficult time visualizing the clamping mechanism.

Thanks,
Louis

[Wolf]

Re: Another OCD build

Wolf,

Any pics to illustrate how that's done? I'm having a difficult time visualizing the clamping mechanism.

Thanks,
Louis

There are many ways to do it. You could make an MDF ring to go over it and use battens screwed to the side-walls for compression, etc.
Later,
Wolf

[Ludo]

Re: Another OCD build

I measured the roundover and it didn't cross, or barely crossed, where the screws would protrude. So... I used 3/4" long screws and a hand powered screwdriver. No power tools when it came to mounting.:eek:

EDIT: I recommend large thread screws. Small threads won't bite well enough and might strip the MDF.

Sounds tricky but doable; something to do early in the morning with a clear head and no distractions

[Ludo]

Re: Another OCD build

There are many ways to do it. You could make an MDF ring to go over it and use battens screwed to the side-walls for compression, etc.
Later,
Wolf

I can picture that.
Thanks, Wolf

[ocdSCHACK]

Re: Another OCD build

What brand of bedliner is that? It looks very even. Did it only take one can?

Looks great!

Blair

I used 1 whole can, maybe 1.25 cans, but now that I learned the technique, It would be way less. Use cheap black primer/ or flat black lacquer to cover everything, and only use the bedliner to add texture. This prevents the texture from getting too thick and saves some bedliner. It was duplicolor Bedliner sprayed over the generic brand of black paint/primer sold at Pep Boys for 2-3$. The bedliner dries quickly and comes out at about 700mph. I sprayed a coat or 2 and sanded it lightly. Then I did a light mist to finish it. It's easier to blend it and spray evenly when you spray further away. But when you spray further away, it adds more texture. Too much texture will collect dust and be difficult to clean. That's why I sanded the texture down some before doing a final coat. I'm now in love with this bedliner. It dries fast and seems like it would make an awesome filler primer. If you use black primer, I recommend the cheap generic stuff from Pep Boys(not totally sure whether it's flat black paint or black primer.) Don't use enamel.

[greywarden]

Re: Another OCD build

Yeah back in HS I used that stuff to cover a 10" sub box i made for my 93 Stang Hatchback (love that car), mainly because my parents were tired of seeing it in the bare scrap mdf i used to build it :rolleyes:

You have to sand really good underneath to get it to stick and stay. I only had chipping after a few months of being in the back of a car, then in my room for a few.

[ocdSCHACK]

Re: Another OCD build

Louis- I think I would have 'clamped' the driver instead of using screws in this case.
Just my 2c,
Wolf

I thought I would need to clamp it initially and did plan to go that route, but when I tested with the screws I used, it was sturdy as $hit. But the driver also has six mounting holes...which allows for more strength than a common four hole speaker. I can assure you for this particular situation, clamping would only be a waste of energy. If one was still skeptical, they could also glue matches, toothpicks, or wood shavings in the screw hole to add strength. I've gone that route when I stripped through MDF using the wrong type of screws.

I should also add: the screws I used were the same length as the MDF thickness, so it is literally impossible to screw totally through the baffle(assuming you're not mounting a speaker that is paper thin.)

Here's a link:http://www.mcfeelys.com/product/0806...at-Head-Screws
The screw threads have much larger spacing vs. PE's, and the entire screw measures 3/4". Plus, they look cool for external use. The phillips-head version PE sells has smaller threads, and they are 3/4" long on the threaded part alone. When it comes to MDF screws, "it's all about the threadsize."

To everyone, thanks for the feedback and compliments,

Schack (aka Shaq Diesel)

[ocdSCHACK]

Re: Another OCD build

As an update, I'd like to talk about the sound on these. It has been a textbook example of baffle-step. In my apartment, which doesn't have a single large open area, a simple crossover sounded great (it measured flat.) When I put them in my old man's wood shop, which is more/less a semi-large open room, they sounded awful. The tweeters would burn your ears off! In my small apartment, with the rear placed near a wall, they were great and efficient. I have redesigned the crossover to sound flat in a large room and would like any tips, comments, or suggestions on how to improve.
-How do you build a speaker for someone you don't know that has a lot of money? Clear treble? Deep bass?
-I have FRD's and ZMA's for anyone willing to help. So far for crossovers, I've build 2 opposite extremes and confused myself on what I should go for.
-What is the typical F3 on a "high quality" mass produced speaker?
-Crutchfield, which I hate as much as BestBuy, claimes 50-36,000Hz on the well rated speakers...but I know that's probably F20.

I need help.

I appreciate everyone's input!!!!!

[ocdSCHACK]

Re: Another OCD build

Alright. My current crossover has some baffle step and plays really low. It can actually vibrate things in my apartment pretty well. I thought the speaker was loose or hitting something because of this sound I kept hearing. It turned out to be a picture frame on the other side of the room was making the noise! In a small room, someone could mistake there being a sub. Here's the annoying part. They are inefficient.
Can I add a resister in series anywhere to increase efficiency, or is this just asking for a house fire?

[critofur]

Re: Another OCD build

Hello,
I would be happy to fiddle with your .FRD + .ZMA files and model your crossover, see if I come up with any suggested changes? Did you measure the woofer impedance in box?

A resistor in series decreases efficiency, not increase. The resistor simply converts electricity to heat....

Please add at least one brace, or a cross brace. Your walls are fairly thick, should be good for the bass.

How about lining the walls with fiberglass or some other fiber material? Listen both ways and see which you prefer? (A small amount of stuffing (such as lining the walls) will make the inside of the enclosure more "dead" - interior midrange frequencies bouncing around inside the cabinet will attenuate faster...

I thought I would need to clamp it initially and did plan to go that route, but when I tested with the screws I used, it was sturdy...

Plywood is particularly good for screwing, as you noticed [big adnvantage over MDF which is bad for screwing].

[MSaturn]

Re: Another OCD build

It's always good to know the final application when voicing/crossing over .. I'd just set it up so you can meet the guy and learn where he'd like to put the speakers. He may put them in a large room (if he's wealthy, he's probably got a lot of large rooms) or he may shove them against a wall. You can't know until he's got them.

[ocdSCHACK]

Re: Another OCD build

Hello,
I would be happy to fiddle with your .FRD + .ZMA files and model your crossover, see if I come up with any suggested changes? Did you measure the woofer impedance in box?

A resistor in series decreases efficiency, not increase. The resistor simply converts electricity to heat....

Please add at least one brace, or a cross brace. Your walls are fairly thick, should be good for the bass.

How about lining the walls with fiberglass or some other fiber material? Listen both ways and see which you prefer? (A small amount of stuffing (such as lining the walls) will make the inside of the enclosure more "dead" - interior midrange frequencies bouncing around inside the cabinet will attenuate faster...


Plywood is particularly good for screwing, as you noticed [big adnvantage over MDF which is bad for screwing].

I actually have the crossover done pretty well now... I would just prefer more efficiency. PM me your email and I can send the files; it can't hurt.

[ocdSCHACK]

Re: Another OCD build

It's always good to know the final application when voicing/crossing over .. I'd just set it up so you can meet the guy and learn where he'd like to put the speakers. He may put them in a large room (if he's wealthy, he's probably got a lot of large rooms) or he may shove them against a wall. You can't know until he's got them.

That's what I was thinking, but it's doubtful I'll meet him. I think I'm gonna have to send a paper with the speakers on how to place them for his tastes, or in other words, how to avoid making them sound awful. They sound good to me and I've switched the x-over too many times to count. I eventually convinced myself he won't attempt to blare them at concert levels, and I should be more objective with my listening. In anything similar to their current placement, I feel pretty confident they'll meet his needs.

By the way, is that picture by your name really you? If so, we're bound to have some mutual friends...assuming we didn't already meet in jail one night.:D EDIT: I'm not trying to sound "gay" or be an as$hole, but that picture cracks me up and reminds me of what my friends and I looked like every morning in college.

[wyomingbob]

Re: Another OCD build

"I have FRD's and ZMA's for anyone willing to help. So far for crossovers, I've build 2 opposite extremes and confused myself on what I should go for. "

Howdy,

I ordered a pair of those 831735s for a first-time project with Dayton DC28FST-8 1-1/8" silk tweeters -- likely to be an MLTL or one of the Chang BVR series with a 2k 24dB crossover. Have been trying to use one of those crossover design worksheets, but figured out it needs specific FRD & ZMA files.

I'd appreciate if you could e-mail a copy of those files <[email protected]> and I'll let you know how the design works out....I've wired operating controls in oil fields and on a 10-story coal loading tower, but crossovers are a whole new challenge for me.

[emilime75]

Re: Another OCD build

I've been wondering about rear mounting woofers for a while now and had concerns if it would effect sound quality in any way. Are there any pros and cons to the method, as far as sound quality goes?