4x OTop 12 (Delta Pro 12A + PSD2013)

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Symphonicmind
Posts: 15
Joined: Mon Apr 09, 2018 7:19 pm

4x OTop 12 (Delta Pro 12A + PSD2013)

#1 Post by Symphonicmind » Tue Aug 13, 2019 2:24 pm

Hi Everyone,
Finally we finished our 4x OTop 12 (Delta Pro 12A + PSD2013). My first impression is:

1. They are really loud. Way way more than I can handle in 20 square meters room even with just 1 OTop12. It destroyed badly the other big Chinese 2x12in LineArray we have tested. Now I understood how the BFM user with 6 pair of OT12s can serve the crowd from 1000-2000 people outdoor.

2. The clarity is really good. It reveals low level details in the mix. With 1 OT12 in room, I listened at around 2m and go left, go right, the sound projection is wide. The center position has the highest level of HF as we expected. We overly worried that the HF projection of OT12 with CD in close range is not enough, but, we were wrong.

3. Delta Pro 12A in this cab is really good performer. Measured THD under 800Hz is awesome. It is mostly under 0.3% at 95dB SPL @1m. It throws really good mid and upper bass, super tight, punchy and LOUD. The ONLY downside of this driver is the weight. It is really heavy for a thin guy like me. The measured level in REW showed around 70dB, however, it is not. In room, we used calibrated SPL meter to check 95dBC Slow reading. The REW data read lower SPL because we reduced mic input gain.

4. The THD of PSD2013 is ok. It is under 1% >800Hz at the same measured condition (I used umik-1 calibrated by CrossSpectrum Lab). I believe this CD is better than that. But I dont know why THD is that high for just 95dB SPL @1m. It makes OT12 sound overly bright when drove at insane in-room level. I guess a tilted-down frequency response will make it less distort and more easy on the ears. And this CD is HEAVY, too.
I think the higher THD from 800Hz and up is the result of 1.2kHz XO with not steep enough filter. If I run this setup by DSP XO, I will use at least LR4 for CD and pad the level of PSD2013 a bit so it will not stressed under high SPL

5. The polarity with this setup should be connected in reversed. We confirmed it with both measurement and listening. After reversed polarity, the mid is richer and fuller. The deep around 1k2 is no longer appeared. So we guessed that we did right thing.

6. The measured frequency response is affected by the room. We dont have luxury of measure it outdoor. However, the room is heavily treated, which is used for flushmounted main monitors. So the frontwall is hard surface. The frequency response showed the dip created by SBIR effect by front wall. Apart from front wall, the treatment eliminates almost any reflections and room mode down to 30Hz. Thus, the frequency response from 500Hz and up can be trusted.

7. Power Response: The power response of OT12 (measured at 1m OnAxis, 15 Degree, 30 Degree) is good. It showed the controlled directivity behavior down to 360Hz which is really good. With 2 OT12 for each side, the horizontal projection is even better. The power response measurement is for 1 OT12.

8. EQ Suggestion: For the best result considering THD, even Power Response, frequency response and listening exprience, I used 3 gentle cut filters at around 1.6, 4.1 and 12.5 kHz. After those 3 basic filter, OT12 REALLY sound awesome.

9. One more thing I want to add: the side port. When I listened to music standing near the rear of OT12s, I can hear the mid pretty easy. I think it is the result of side port. Should it be the potential feedback problem when we use it in relatively small to medium indoor show? At those situation, we dont have much choice to place OT12s far enough from stage, so I am really worry about feedback right now.

Overall, I really happy with the project. If we make OT12 again, we will try with Delta Pro 12-450 and F151M-8. We dont think this combination can sound as good as current setup because Delta Pro12A looks a bit better on paper than 12-450. And PSD2013 has higher power handling ability and lower Fs than F151M-8, IMO, it can be better for 3rd Order 1.2kHz recommended XO. But the reduction of weight for this new combination may be another reason to try.

Edwards.
Attachments
OT12.jpg
THD.jpg
OT-12-Reversed Polarity.jpg
OT12-PowerResponse.jpg
Last edited by Symphonicmind on Fri Aug 23, 2019 3:02 am, edited 1 time in total.

Bruce Weldy
Posts: 6799
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: 4x OTop 12 (Delta Pro 12A + PSD2013)

#2 Post by Bruce Weldy » Tue Aug 13, 2019 3:16 pm

Very nice looking build.

Any reason not to use the 2512 or 3012HO since you want to save the weight?

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

himhimself
Posts: 275
Joined: Fri Nov 13, 2015 9:34 pm
Location: Bloomington IN

Re: 4x OTop 12 (Delta Pro 12A + PSD2013)

#3 Post by himhimself » Tue Aug 13, 2019 7:55 pm

9. One more thing I want to add: the side port. When I listened to music standing near the rear of OT12s, I can hear the mid pretty easy. I think it is the result of side port. Should it be the potential feedback problem when we use it in relatively small to medium indoor show? At those situation, we dont have much choice to place OT12s far enough from stage, so I am really worry about feedback right now.
I've only had one real outing with my otops so far, but also noticed how much program came out the sides. Enough that there was a little side party off 90 degrees from the speakers, probably 75 feet away, and some of them thought it should be turned down!
2xT30 (20", 3012lf)
4xOtop Jarray

Bruce Weldy
Posts: 6799
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: 4x OTop 12 (Delta Pro 12A + PSD2013)

#4 Post by Bruce Weldy » Tue Aug 13, 2019 8:55 pm

Not enough fingers and toes on this forum to count the number of shows I've done with the ports of two OT12s being 4 or 5 feet away from my vocal mic......it ain't a problem.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Symphonicmind
Posts: 15
Joined: Mon Apr 09, 2018 7:19 pm

Re: 4x OTop 12 (Delta Pro 12A + PSD2013)

#5 Post by Symphonicmind » Tue Aug 13, 2019 11:08 pm

Bruce Weldy wrote:
Tue Aug 13, 2019 3:16 pm
Very nice looking build.

Any reason not to use the 2512 or 3012HO since you want to save the weight?
Thank you very much. It is because equipvalent Neo drivers is 1.5x expensive compared to Ferrite in our area. And the 3012HO is too expensive.

Deltalite 2512 is 1.3 times more expensive than Delta Pro 12A. It also handle less power. I also have tested Delta Pro 12A before, and it really impressed me with its performance, both listening and measured data.
himhimself wrote:
Tue Aug 13, 2019 7:55 pm
I've only had one real outing with my otops so far, but also noticed how much program came out the sides. Enough that there was a little side party off 90 degrees from the speakers, probably 75 feet away, and some of them thought it should be turned down!
Thank you for giving me real life experience. I agreed, the sound projection from the side of speaker is really clear. I stand in the middle of 4 OT12s (behind the cabinet face), I can hear everything in the mix. Maybe that is not problem with outdoor or big stage. But for small in door stage, I hope it will not generate much feedback.
I have setup 4 FBT CLA-406 LineArray before in the same bad situation, in the stage, we dont even need to use stage monitor. Because we can hear everything that CLA-406 throws out. lol. And yes, it caused a lot of feedback.
Bruce Weldy wrote: Not enough fingers and toes on this forum to count the number of shows I've done with the ports of two OT12s being 4 or 5 feet away from my vocal mic......it ain't a problem.
Thank you, how far the OT from the stage edge? and How wide was the stage?
There is one people (jbell) modded OT12's port and put it on the front of mid horn to reduce mid leakage from the side of speaker and he reported good results. I think Bill must have good reason to place it on the side.
I hope Bill could share his thought, too.

Bruce Weldy
Posts: 6799
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: 4x OTop 12 (Delta Pro 12A + PSD2013)

#6 Post by Bruce Weldy » Wed Aug 14, 2019 8:51 am

Symphonicmind wrote:
Tue Aug 13, 2019 11:08 pm
Bruce Weldy wrote: Not enough fingers and toes on this forum to count the number of shows I've done with the ports of two OT12s being 4 or 5 feet away from my vocal mic......it ain't a problem.
Thank you, how far the OT from the stage edge? and How wide was the stage?
I'd say we did 25-30 shows on a stage that was only 15 feet wide with the speakers tucked right up against the stage. Not kidding when I say that my mic was only a few feet away from the port.

Here's a pic of that stage - it's a tight little place....
IMG_1076.JPG
I wouldn't worry about feedback from those side ports - you are 100 times more apt to get feedback from your monitors.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Symphonicmind
Posts: 15
Joined: Mon Apr 09, 2018 7:19 pm

Re: 4x OTop 12 (Delta Pro 12A + PSD2013)

#7 Post by Symphonicmind » Thu Aug 15, 2019 12:51 am

Dear Bruce, Thank you a lot for your information. Now I am more confident to setup for that indoor gig. :D
Have you ever tried the new CD that Bill recommend, which is Eminence F151M-8? I want to try it next time I build test speaker with Delta Pro 12-450 and F151M-8.

Bruce Weldy
Posts: 6799
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: 4x OTop 12 (Delta Pro 12A + PSD2013)

#8 Post by Bruce Weldy » Thu Aug 15, 2019 8:34 am

Symphonicmind wrote:
Thu Aug 15, 2019 12:51 am
Have you ever tried the new CD that Bill recommend, which is Eminence F151M-8?
No, I haven't built anything in awhile....in fact, I bought a couple of extra NSD2005 after Eminence quit making 'em ...... just in case.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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