Help me cheat and get my OTop 12s sounding good without RTA

Message

Mark Coward · #1 Post by **Mark Coward** » Thu May 01, 2008 1:37 pm

The OT12's should be fairly close to flat, one of the nice features of the design. I'm not sure if there is a chart with the melded array, but you can see from this OT2x12 crossfire chart how flat the response is. Most folks, me included, think that ruler flat response is too trebly in practical use, I'd try a roll off from 3k upwards. Also, when using all of your cabs, the equivalent of two OT2x12's per side, the response will flatten out even more.

Ron K · #2 Post by **Ron K** » Sun May 11, 2008 9:09 pm

I generally cut about 3 db at 400 and 630 and as Mark pointed out flat response is usually very trebly. I use a bit higher roll off around 5K - 6K on up. I dont mind the 3 K range as it helps in the vocal range for live. You may find this too much for recorded compressed media and may want to experiment with the HF roll off a bit.

Pretty much I like the box as it is and EQ comes fairly easy and doesn't take a whole bunch of time by ear.

Room reflections will dictate the remainder of the EQ needed. If you plan on cutting them open in your living room be careful as they get very loud with little power. 4 can be deafening and damage your hearing!

jeffbabcock · #3 Post by **jeffbabcock** » Mon May 12, 2008 12:23 pm

Mark Coward wrote:The OT12's should be fairly close to flat, one of the nice features of the design. I'm not sure if there is a chart with the melded array, but you can see from this OT2x12 crossfire chart how flat the response is. Most folks, me included, think that ruler flat response is too trebly in practical use, I'd try a roll off from 3k upwards. Also, when using all of your cabs, the equivalent of two OT2x12's per side, the response will flatten out even more.

You will probably find that OT12's are a bit more peaky when measured than the SPL charts on the site indicate. It all depends on your settings in your measurement app of choice in terms of how smooth the measurement appears. If you look at the T48 measurements from the subwoofer shootout that Leland attended, the response is similar to the SPL chart on the site however you will see more peaks and dips in the response. The same is true of the DR200 smaart measurements that were taken a while ago. The SPL charts on this site are fine to give you an idea of the general response of the cab but are a bit smoother than how they will really measure in singles in a program like Smaart. Of course this is the case with most SPL charts that manufacturers provide, and in Bill's case he often is accounting for multiple driver options etc and must account for some slight variance. Of course this response will also change somewhat as you add cabs.

After much deliberation, I am finally building some OT12's (with the help of Greenman), when we get those done I will try to find a day to spend some time with them and Smaart.

I do agree that "flat response" is a good starting point but is not generally what the average listener would think sounds best. I try to be conservative with roll off though, and 3k would be lower than I would usually want to do that. I guess it depends on the boxes and the most important thing is using your ears to find what sounds right for the application.

Cheers
Jeff

Mark Coward · #4 Post by **Mark Coward** » Mon May 12, 2008 1:46 pm

jeffbabcock wrote:
I do agree that "flat response" is a good starting point but is not generally what the average listener would think sounds best. I try to be conservative with roll off though, and 3k would be lower than I would usually want to do that.

I suggested that from looking at the chart above, the peak around 3k. I usually try to roll off from 5k, when using RTA.

jeffbabcock · #5 Post by **jeffbabcock** » Mon May 12, 2008 8:39 pm

No worries Mark, based on that spl chart 3k seems reasonable. I'm sort of with Ron on the idea of keeping a bit in the 3-4K range as it can in some cases give better vocal clarity, but again it really depends on the application and whether for live or tracks etc.

I will try to take some measurements when mine are done and see what happens. I have worked with some fairly highly regarded top boxes such as the EAW NT series, Renkus Heinz coentrant and complex conic boxes, EAW, JBL, Meyer line arrays etc. My expectations are high. I am eager to see how good the Otops are with no processing and also how good they can be made via dsp etc. While they may not have the same output as a DR, I suspect the potential is there for it to have better phase response and sound a bit better for my needs. I would rather also have more boxes (otop12) in a longer line than fewer high output boxes (DR200 or 250) in a short line as it will yield better coupling extension into the LF and better pattern control.

Ron K · #6 Post by **Ron K** » Mon May 12, 2008 9:20 pm

jeffbabcock wrote:No worries Mark, based on that spl chart 3k seems reasonable. I'm sort of with Ron on the idea of keeping a bit in the 3-4K range as it can in some cases give better vocal clarity, but again it really depends on the application and whether for live or tracks etc.

I will try to take some measurements when mine are done and see what happens. I have worked with some fairly highly regarded top boxes such as the EAW NT series, Renkus Heinz coentrant and complex conic boxes, EAW, JBL, Meyer line arrays etc. My expectations are high. I am eager to see how good the Otops are with no processing and also how good they can be made via dsp etc. While they may not have the same output as a DR, I suspect the potential is there for it to have better phase response and sound a bit better for my needs. I would rather also have more boxes (otop12) in a longer line than fewer high output boxes (DR200 or 250) in a short line as it will yield better coupling extension into the LF and better pattern control.

Would Jeff be interested in SMARRTing a O-Top with a DeltaPro12A in it? I would happily ship one up if you got the time to do it!

jeffbabcock · #7 Post by **jeffbabcock** » Tue May 13, 2008 9:56 am

Hey Ron,
If you are sure that you prefer the sound of the DeltaPro 12A over the Deltalite then I might just be inclined to try a couple of them to compare. I could just order a driver or 2 and slap them in my Otops which are currently under construction.

Is the difference enough in your opinion to justify the additional weight? And do you notice this difference when the cabs are in a vertical array or mostly just when they are running as singles? I will very rarely be running in singles.

BTW it will probably be June sometime before the Otops are done and I have time to take measurements.

Thanks
Jeff

Ron K · #8 Post by **Ron K** » Tue May 13, 2008 6:23 pm

I only have 2 boxes with DeltaLites in them so I cant array in that configuration other than stacking just 2. Even stacked I still favor the DeltaPros as far as attack goes.They seam faster and ballsyier if thats a real word!

I'm doing an outdoor show at the end of the month (25th) so I'll snap some pics and do some distance listening. If I have time I'll run my window analyzer and take some pics of the graphs and the analyzer. I'm planning on an early set-up that day so time should be in my favor.

I really want to try 3 per side arrayed but I have yet to run into a gig that needs that much.I can probably get away with it Sunday but I'm thinkin it would be overkill.

Do I think the added weight is worth it? Yes I do at this point in time. I plan on building 2 more with DeltaLites but probably not until summer hits. Right now I have 2 smaller systems that need to be finished and put out on rental by the end of this month!

I just finished an install at a House of Worship and I broke ground in the back yard for a small studio/practice room or whatever Tom Foolery me and my Son can conjure up! Me plates kinda full!

jeffbabcock · #9 Post by **jeffbabcock** » Wed May 14, 2008 4:42 pm

OK, if you think it is worth the extra weight then I think if I decide to do another 4 otops then I will do those with the Delta Pro12A as you mention. However I'm wondering if the response is similar enough to array them with Deltalite based boxes..... hmmmm. Tough call. You're really making me think about sending back the Deltalites right now... I haven't opened them up yet but would of course have to pay restocking etc...... doh!

You have really got me second guessing my build Ron.....

Maybe we should move this discussion to the Otop forum so Bill and others are more likely to chip in their thoughts...... ???

Ron K · #10 Post by **Ron K** » Thu May 15, 2008 3:02 pm

Why build one. I'll send you one up and you can make up your mind and A/ B them.Simple enough. You're not that far. or I could run up to Buffalo or wherever in upstate NY (bout 6 hrs for me) and you can drive over and pick one up. We can meet have lunch swap war stories etc.

Best way to find out is listen to one. A / B it with a deltaLite and you will have your answer. Since you are good with SMARRT you could even analyze them . Return when finished. I'm on my way to an armada of them anyhow so I wont miss one! I'll probably have 2 more before the end of June!

I could also just send you a driver! I have several of them anyhow as I used them in some monitor wedges and my old M80 Fiberglass Mids! That was my reason for using them in the first place. I had them lying about brand new and a few used. The new ones were spares I never used. Was always a very solid driver for me. A real banger very similar to the EVM 12L ProLine!

Just say the word and I'll ship you one.Ship it back after you're done.