OmniTop 12 build

Post your build odyssey here.
Message
Author
Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#46 Post by Fastskiguy »

I couldn't find how to change the background but I switched the trace to white and it shows up a little better. I'm looking forward to building the second one....there are some things I hope to do a lot better on #2!
Attachments
IMG_9950.jpg
Screen Shot 2023-03-14 at 9.55.26 AM.png

User avatar
Bill Fitzmaurice
Site Admin
Posts: 28590
Joined: Tue May 02, 2006 5:59 pm

Re: OmniTop 12 build

#47 Post by Bill Fitzmaurice »

Those peaks and dips above 1kHz may indicate floor bounce and/or measuring with the mic too close to the cab.

Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#48 Post by Fastskiguy »

The mic was pretty close so maybe that is it. I’ll give it another try someday….in the meantime it’s moved into the garage with the tweeter array for the second one helping out :)

Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#49 Post by Fastskiguy »

The crossover is working too
Attachments
814B3608-D79E-4171-BF2C-1D3910F59645.jpeg

User avatar
Bill Fitzmaurice
Site Admin
Posts: 28590
Joined: Tue May 02, 2006 5:59 pm

Re: OmniTop 12 build

#50 Post by Bill Fitzmaurice »

For a good result with a vertical driver array you want to measure from at least three times the array height, preferably more.

Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#51 Post by Fastskiguy »

Ah ok I’m sure I wasn’t that far away. How about the distance away from buildings and walls….are there any guidelines about how far away from the house I should be?

User avatar
Bill Fitzmaurice
Site Admin
Posts: 28590
Joined: Tue May 02, 2006 5:59 pm

Re: OmniTop 12 build

#52 Post by Bill Fitzmaurice »

At least two wavelengths. That's 25 feet at 100Hz. The absolute best method is to take two measurements. The first is with the cab on the ground, the mic an inch or two above the ground. The second is with the cab on it's back, the mic suspended above it, the same distance away as with the ground plane measurement. With the second measurement you'll see a notch, where the reflected wave off the ground and the original wave meet 180 degrees apart. Just above that notch the two measurements will have the same SPL. Splice them together at that frequency. This gives a true half-space anechoic result, just like in a $100k anechoic chamber.

Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#53 Post by Fastskiguy »

Awesome information, thanks :)

Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#54 Post by Fastskiguy »

The second one is so much easier than the first one! Still struggled with the jig saw and baffle but it came out better. This time it’s really fun :)
Attachments
B7D8DBD8-DE63-44D9-9DB2-977990401CF4.jpeg

User avatar
Bill Fitzmaurice
Site Admin
Posts: 28590
Joined: Tue May 02, 2006 5:59 pm

Re: OmniTop 12 build

#55 Post by Bill Fitzmaurice »

Most of what you're doing with the first one is figuring out how to do it. After that it's pretty easy.

User avatar
fender3x
Posts: 647
Joined: Mon May 15, 2006 11:51 am
Location: miami

Re: OmniTop 12 build

#56 Post by fender3x »

That is an amazingly clean cut with a jigsaw.
One man's magic is another man's engineering. --Heinlein

1 x DR250
1 x T39
1 x Omni 10

Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#57 Post by Fastskiguy »

Loving the sound and have the first t45 under construction:)
Attachments
841244F9-E501-47B4-B756-D8C284790342.jpeg
16FE858E-23E8-48D9-8390-F0496CB836BB.jpeg

Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#58 Post by Fastskiguy »

Progress report....so the first T45 is coming along just fine, although I went off plan on the bracing. But it's gonna be pumping out sound in a few days (hopefully!). The amp I planned to use for the T45s has a loud clicking sound and it might be in the process of dying so I need some suggestions on how to power this system. Based on the charts of the wall loaded T45....I pretty much need 3 good volts for my garage....maybe less!

I've got that tube amp thing, this thing https://www.parts-express.com/Lepai-2.1 ... quantity=1 and a bluetooth receiver. I'm thinking....bluetooth to the receiver then send the signal to both amps, one for the Otops and one for the T45 (or T45s if the second one gets built). My understaning is that I need some eq in there somewhere. What's my best option here for this garage system? Can I add something in there that will do what I need or am I better off just starting over? Money isn't growing on trees but it's a fun project and if I need to spend a few bucks that is OK. The garage hits 100 humid degrees in the summer (for like 6 months)....if that matters.


Thanks guys :)

Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#59 Post by Fastskiguy »

Here are some progress pics
Attachments
A9090F98-2823-4EC6-A853-EA7293F0DED6.jpeg
6503AE1E-BC31-46DC-8AA6-C0BDB997FFF7.jpeg

Fastskiguy
Posts: 176
Joined: Tue Dec 20, 2011 8:11 pm

Re: OmniTop 12 build

#60 Post by Fastskiguy »

One more…
Attachments
1E77AB38-C662-4036-8D5F-95990549FEAA.jpeg

Post Reply