Omnitop12, my first
- Bill Fitzmaurice
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Re: Omnitop12, my first
Do it outdoors to remove the room from the result, on axis and 45 degrees off-axis.
Re: Omnitop12, my first
Yes sir, I will do that. Today I cut two pieces of wood and mounted up the dual horns in a cabinet. Perhaps tomorrow I will be able to set up and do some testing.
Advanced Concepts Underground Audio
Re: Omnitop12, my first
Today I have collected a bunch of data and will attempt to present it. First I turned off all EQ and verified phase and spl at the 2k filter point. I noted that the ASD-1001 drivers were in phase with my phase reversed compared to the mids. I am running 4th order butterworth filters through my driverack. I left the gains between the mid and high output the same for all tests. I captured traces of the spectrum as well as with high and mid cuts if you value seeing them. I also ran on axis and 45 degrees off axis. my measuring mic was about 8ft from the speaker for this set of tests.
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Re: Omnitop12, my first
here is the data I collected for dual loaded asd-1001 horns, on axis, 45 degrees off axis, comparing 1 asd-1001 vs 2 asd-1001 on and off axis.
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Re: Omnitop12, my first
I switched over to 1.2k filter crossover at 4th order butterworth, here is a single f151m horn driver, then comparing dual asd-1001 with it. again the gain structure between the high and mid is unchanged. I note that for proper phase alignment with the f151m drivers the normal phase polarity is correct as apposed to the asd-1001 with was flipped! strange maybe but it is what it is.
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Last edited by ACUA on Sun Nov 20, 2022 5:53 pm, edited 2 times in total.
Advanced Concepts Underground Audio
Re: Omnitop12, my first
this round focuses on dual loaded f151m configuration, with on axis, 45degrees off axis and comparing single horn f151m and then dual asd-1001 on axis comparison.
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Re: Omnitop12, my first
finally this post will show the spectrum analysis of the plastic Chinese horns I purchased, on axis off axis 45 degrees, then compare to the dual aluminum horn with f151m drivers and the asd-1001 drivers.
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Re: Omnitop12, my first
If you want to see a specific chart configuration that I missed above let me know and I will post one up.
My conclusion is that these Chinese plastic horns work fine. the ones I have do require dual loading to fit an otop12 cabinet. I like having dual drivers as it gives me head room and should have higher fidelity. my conclusion regarding a 2k filter point or 1.2k, I already had this conclusion but am just organizing my rig properly, yes a million times over 1.2k is better in my personal taste and opinion. the f151m driver looks to be a pretty clear 3db louder with same input compared to the asd-1001 drivers.
I am super excited to get all these f151m compression drivers hooked up in my rig. I look forward to using these Chinese plastic horns, it will be easy to assemble and I don't have to build anything really.
My conclusion is that these Chinese plastic horns work fine. the ones I have do require dual loading to fit an otop12 cabinet. I like having dual drivers as it gives me head room and should have higher fidelity. my conclusion regarding a 2k filter point or 1.2k, I already had this conclusion but am just organizing my rig properly, yes a million times over 1.2k is better in my personal taste and opinion. the f151m driver looks to be a pretty clear 3db louder with same input compared to the asd-1001 drivers.
I am super excited to get all these f151m compression drivers hooked up in my rig. I look forward to using these Chinese plastic horns, it will be easy to assemble and I don't have to build anything really.
Advanced Concepts Underground Audio
- Bill Fitzmaurice
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- Posts: 28645
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Re: Omnitop12, my first
The Chinese horns look good, too bad there doesn't seem to be a domestic source for the,.
Re: Omnitop12, my first
ACUA, that's a butt load of data! Wow, thanks! Gonna take a couple days to take it all in before conversing about it all. So awesome!
If the monthly volume of OTop plans sold was sufficient to make it a relatively safe test investment, I'd consider personally buying a years worth and sell them through Amazon and/or ebay just to see how it goes. Partially out of community support, partially out of making a little dough on the side.Bill Fitzmaurice wrote: ↑Sun Nov 20, 2022 8:23 pm The Chinese horns look good, too bad there doesn't seem to be a domestic source for them.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded
Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421
Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421
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Re: Omnitop12, my first
ACUA. good job!
I'm a little surprised that you have response in the 20- 40Hz region, was there no HP on the mids?
Also, since your 2 x HF drivers are wired in series, that allows twice the voltage swing, so you could get less of a lump in the 1-2K region with a less severe filter and the 1.2K cross point, so that would be a good choice perhaps, without the risk of hurting the HF drivers....
I'm a little surprised that you have response in the 20- 40Hz region, was there no HP on the mids?
Also, since your 2 x HF drivers are wired in series, that allows twice the voltage swing, so you could get less of a lump in the 1-2K region with a less severe filter and the 1.2K cross point, so that would be a good choice perhaps, without the risk of hurting the HF drivers....
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...
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Re: Omnitop12, my first
I'll order up when you do man..
AT8 14", AT10 19", T30 28" LAB12, T48 36" 3015LF, THT 20" LAB15, SLA 4x3"/4x4", CArray 6x4", TLAH, TLAP, J10 FLat, J12 Flat, OT12 Flat, OT15 CD, SLAP 2x6"/4x6", WH8, DR280 Mld'd, XF210. Next J10L
Re: Omnitop12, my first
I was running a single tuba45 cab for the low end, I have it low passed at 100hz 2nd order butterworth, I believe! The traces that represent a mid-cut, it shows as a dip in the 80-2k hz range, but the low frequency content is always represented as i never muted the sub.Grant Bunter wrote: ↑Mon Nov 21, 2022 1:44 am ACUA. good job!
I'm a little surprised that you have response in the 20- 40Hz region, was there no HP on the mids?
Also, since your 2 x HF drivers are wired in series, that allows twice the voltage swing, so you could get less of a lump in the 1-2K region with a less severe filter and the 1.2K cross point, so that would be a good choice perhaps, without the risk of hurting the HF drivers....
I did not play around with different filter types for this round of testing. Looking at the graphs I am inclined to play around with filter configuration as most these graphs do not generate a perfect 800-2200hz interaction, but I believe that this does represent roughly the behavior of a single horn, a modified dual horn, these Chinese plastic horns. It also gives some basic representation of an ASD-1001 driver as well as the F151m-8 driver in those situations. I did not mount up the ASD-1001 drivers into the plastic Chinese horns, but that would be on my lift for next time.
Advanced Concepts Underground Audio
Re: Omnitop12, my first
I wish to express my opinion regarding the build quality of these plastic Chinese horns. The consistency of the 16 units I received is all good. Nothing was damaged or in any way undesirable. The thickness and general structural make up of these units are in my opinion, sufficiently nice. The front has a shiny plastic finish. The mounting plate is plenty thick in visual appearance, but I do have to bore the mounting holes out slightly as a 1/4-20 bolt does not fit without running a 1/4 bit through it first. The plastic is probably on the soft side! When I went to torque down the nuts to hold the f151m drivers the plastic quickly deflects and warps the flange of the horn. I have not broken one of these horns yet, once i noticed this warpage I quickly loosened up the nuts and the flange returned to straight quickly. The plastic is soft not brittle. I can hardly compress the lock washer to flat before the plastic flange has warped beyond my comfort level. I optioned for some fender washers which help a fair amount but not to my complete satisfaction. I am going to look into a more robust solution to allow better pressure distribution upon tightening the retaining nuts of the drivers to the horn flanges.
I wish to issue caution to aspiring consumers of this product that this is the weakest link regarding them, besides being sourced in China of course. Be careful regarding the shipping option selected should you option to buy from aliexpress.com as their price per unit ratio is highly flawed, there was a resonance to the price drop relative to number of units in cart and sometimes the shipping cost per unit ratio spikes depending on number of units shipped. May have to do with package sizing requirements but look closely at it. I purchased all 16 units in one order and using the cheapest shipping option they offered it came out cheaper per unit than any of the other methods I modeled up. The claim was that my order was going to be 30-40 days in delivery transit but only took two weeks to arrive. I spent about an hour removing the foam and plastic wrap to get to my product it was both exhausting, messy and fun. The use of a sharp blade would have helped!
I also modeled the dual plastic horns in the otop12 cab with a piece of wood placed between the horns and none of my messing with it generated any notable change in the graphed spec analysis, so I am likely to option to leave the 3/4in gap between the horns on final install. I figure that the gaps between horns when stacked between cabs is close to 2in that if it was a real big issue something would be done to compensate. I wanted the horns as far separated as possible to hopefully support better summation when stacked up with other cabs.
Advanced Concepts Underground Audio
Re: Omnitop12, my first
I have not done anything yet to stress these plastic horns. I worry some about their structural potential. I will be working to configure my rig with these horns and if I run into any issues, I shall promptly notify you. If you look around that aliexpress.com website, there are a lot of different horns to be found. There was as I recall, a unit that was right near 14in tall that was designed to house three 1in dia. horns, but the price was a little higher and I hesitate to want three cds per cab. there may be other options out there that will work well enough once I found what I bought I quit looking.Seth wrote: ↑Sun Nov 20, 2022 9:16 pm ACUA, that's a butt load of data! Wow, thanks! Gonna take a couple days to take it all in before conversing about it all. So awesome!
If the monthly volume of OTop plans sold was sufficient to make it a relatively safe test investment, I'd consider personally buying a years worth and sell them through Amazon and/or ebay just to see how it goes. Partially out of community support, partially out of making a little dough on the side.Bill Fitzmaurice wrote: ↑Sun Nov 20, 2022 8:23 pm The Chinese horns look good, too bad there doesn't seem to be a domestic source for them.
I have been wanting to 3d print these horns for a while now. I wonder how hard it would be to build a proper mold and injection manufacture a quality domestic option?
I will invest if it looks like a functional niche in the market! let me know what you are thinking!
Advanced Concepts Underground Audio