OT12 Phase Plug

[Wasichu]

Hey guys! First post here, but I’ve been sold on BFM for awhile. I’ve lurked for years, and this forum has been a wealth of information. You’ve never heard dubstep until you’ve heard it on a T60.

So I have two OT12s that were purchased off the forum by a colleague. They are currently loaded with Beta 12s and compression horns with ASD1001s. I’m looking for some better clarity and output, so I ordered a pair of Kappalite 3012HOs and a pair of FaitalPro HF108s and FaitalPro STH100 horns, at the recommendation of said colleague. My intention is to replace the OT12 compression horn with the Faital horn and cross them over at 1.2khz. So here’s my question: these cabs have a 5” phase plug. A 6” phase plug is speck’ed for Bills compression horn crossed at 1.2khz. What am I giving up by running this setup with the 5” plug, and which horn does the phase plug actually affect? Would it be worth the effort to add back material to have a 6” plug? I’m all ears, feel free to poke holes in this idea. Thanks!

[Bill Fitzmaurice]

With the 1.2kHz HF the 6" plug works better than 5". You could add 1/4" thick 6" circles to the front of the 5" plugs.

[Bruce Weldy]

Are you mounting those horns horizontally like the are supposed to be? They are an 80x70 dispersion - really narrow and if you turn 'em vertical, even more so. I'd keep the horns you have in the cab and just swap out the drivers and crossovers.

Especially if you decide to ever add two more OT12s, then they will couple properly.

[Wasichu]

Thanks Bill, that answered my question. I will add the 6” disc if I’m not satisfied.

Are you mounting those horns horizontally like the are supposed to be? They are an 80x70 dispersion - really narrow and if you turn 'em vertical, even more so. I'd keep the horns you have in the cab and just swap out the drivers and crossovers.

Especially if you decide to ever add two more OT12s, then they will couple properly.

That was my intention, Bruce. One thing I haven’t been able to find is approximately what the dispersion is on the OT12 horns. I’m not at all against keeping them, I need wide dispersion for the room I’m currently set up in. I may play around with swapping the horns back and forth. Are the HF108s an acceptable sub in Bill’s compression horn?

[Wasichu]

Also Bruce, we actually have a matched set of four, my buddy has the other two.

[Bill Fitzmaurice]

FaitalPro STH100 horns are not suitable, unless you will never stack them. I seriously doubt that they have wider dispersion anyway. Loaded with a 1.2kHz driver dispersion of the plans HF horn (-6dB) is 90 degrees.

[Wasichu]

What about the HF108 driver?

[Wasichu]

What about the HF108 driver? I am pretty new to all of this as you can probably tell. 90 degrees is quite acceptable to me, I will stick with the hf horns from the plans if there’s no issue running the HF108s with them.

[Bill Fitzmaurice]

It will work, but it's absurdly expensive, more than twice what you need to pay.

[Wasichu]

Noted. Thanks for your help Bill.

[Tom Smit]

Wasichu, welcome to the forum!

Have you thought about a melded array for one set. The cabs could be place on the bottom of the stack for 120 degrees of dispersion. The cabs with CD could be placed on top of the cabs with melded arrays for longer throws.

[Bruce Weldy]

Also Bruce, we actually have a matched set of four, my buddy has the other two.

Then you should definitely stick with the horns that are in them already. They have a wider dispersion than the ones you listed and they will couple properly - the ones you listed won't.

Bill's right about the driver.....no need to spend that much money.

[Bruce Weldy]

Sent you a PM....

[Wasichu]

Had a great New Years with the two OT12s, and four T60s. I didn’t have time to change the phase plugs with having to get everything else ready in time. I did a quick outdoor measurement of the omnis the day of, there was a pretty substantial drop off at 1.2khz. Eq helped some, but I will definitely be modding the phase plugs in the coming weeks. The Kappalite 3012HO was a substantial improvement, I will be modding the other two Omnis shortly as they are now in my possession. Overall quite happy with the dispersion and amazing clarity from the compression horns at such a short listening distance.

[Wasichu]

Wasichu, welcome to the forum!

Have you thought about a melded array for one set. The cabs could be place on the bottom of the stack for 120 degrees of dispersion. The cabs with CD could be placed on top of the cabs with melded arrays for longer throws.

Thanks Tom, it is definitely something I’d like to try at some point. I see a lot of mixed reviews on the Goldwood 1016 piezos, does anyone on the forum have any experience with these? Reviews are somewhat better. https://www.parts-express.com/GRS-PZ101 ... quantity=1