bottom mouth?
hello guys, i'll be starting the build of one keystone sub, i got four units of Beyma 18g50 4ohms drivers. (700 aes, 9mm xmax), the sims looks very good.
my question, adding a ouput plate in the bottom of the box and closing the mouth (keystone shape), the sims show a increase low frq ouput about 10hz more, but missing 2 dbs and adding some peaks, i'm rigth?.
the idea is make a removables panles to get the 2 option mouths and get the 2 responce too (keystone shape panel and botton panel).
thanks art for share this design!
greetings from Argentina!
pd: sorry for my bad english.
hello guys, i'll be starting the build of one keystone sub, i got four units of Beyma 18g50 4ohms drivers. (700 aes, 9mm xmax), the sims looks very good.
my question, adding a ouput plate in the bottom of the box and closing the mouth (keystone shape), the sims show a increase low frq ouput about 10hz more, but missing 2 dbs and adding some peaks, i'm rigth?.
the idea is make a removables panles to get the 2 option mouths and get the 2 responce too (keystone shape panel and botton panel).
thanks art for share this design!
greetings from Argentina!
pd: sorry for my bad english.
Here
http://www.data-bass.com/data?page=system&id=119&mset=131
you can find good measurements and review of the Orbit shifter pro. It is a beast that can get 137 dB continous with the dedicated SpeakerPower 4000 amp. If you compare it with the Othorn sub , and the HR sims between othorn and Xoc 1, you can get an ideea of what is the difference between xoc, keystone, danley and JTR. If you ask me, I would bet for the JTR in sheer output.
But, don't forget about brand recognition, resale value and how people perceive quality. If you rent audio equipment and you say it is made by you, it will be hard to convince a potential client that what you can build is better than an 8000$ pair of subs from Qsc or JBL or others.
http://www.data-bass.com/data?page=system&id=119&mset=131
you can find good measurements and review of the Orbit shifter pro. It is a beast that can get 137 dB continous with the dedicated SpeakerPower 4000 amp. If you compare it with the Othorn sub , and the HR sims between othorn and Xoc 1, you can get an ideea of what is the difference between xoc, keystone, danley and JTR. If you ask me, I would bet for the JTR in sheer output.
But, don't forget about brand recognition, resale value and how people perceive quality. If you rent audio equipment and you say it is made by you, it will be hard to convince a potential client that what you can build is better than an 8000$ pair of subs from Qsc or JBL or others.
Juan Carlos,
You can see the results of "step down" covers in post #262.
To extend the low frequency range, cover the upper, not the lower portion of the Keystone exit.
Cheers,
Art
Thanks for the quick replies to the Keystone output. I have considered the value of name brand v home built, and I have considered eventual resale also. I will check the comparative links.
I do audio professionally, and know I can build well; however, I am a small operator now that I am semi retired and work alone. I want to go loud, but small. It can be a challenge, and get expensive, so I am considering my options carefully, and have been for the past few months. Thanks for the helpful replies.
I do audio professionally, and know I can build well; however, I am a small operator now that I am semi retired and work alone. I want to go loud, but small. It can be a challenge, and get expensive, so I am considering my options carefully, and have been for the past few months. Thanks for the helpful replies.
I do not rent my gear. It is for my use. It only gets used if I go with it. But "homemade" is still just that - I agree. I have read the databass OSPro report. I have looked at some of the JBL double 18's and the output is not the same as the Danley / JTR. I do own some QSC and JBL subs, but they are single 18's and 15's. I need more output for larger venues / outdoors to keep up with my tops. Thanks
I have sold my Keystone/Paraline system to a younger man, after 41 years in the production business, am semi retired now myself.
That system used a pair of Keystones below 28 eight inch horn loaded speakers and ten EVDH1A 3" diaphragm drivers.
Covered as many as 5000 persons for outdoor family type rock events.
Art
It would be nice if someone had some measured comparisons of all these designs.
PASC did build the Xoc1 TH18 and Keystone but from previous posts I don't find his input to be very reliable. A lot of his comments are purely subjective and what little he did measure was not very reliable either. Let's give him the benefit of doubt though and just say the Keystone is probably a bit louder than the TH18, maybe by as much as a couple of db. i'd really like to see a measured head to head data-bass style though.
And we know from radulescu (who seems a bit more reliable than PASC) that the Xoc1 and the commercial TH118 are very close in max output.
What I can tell is that I cannot hear any difference between the output of the 2 but the measurements sais Danley go 1 dB more on a bridged K8. From here - http://www.diyaudio.com/forums/subwoofers/190635-th-18-flat-35hz-xoc1s-design-222.html#post4700416
That puts these 3 cabs within 3 db (or less) of each other in max output. So those 3 are pretty close. Are all 3 using the same driver as reported? I don't have time to check on that.
Now let's compare the Othorn vs the JTR Orbit Shifter Pro. As measured by data-bass -
An externally hosted image should be here but it was not working when we last tested it.
The JTR has a slight advantage above 50 hz but who cares about that? It was also tested up to only 3 db of compression whereas the Othorn showed 5 db of compression at it's high power sweep, so the Othorn was pushed a bit harder than the JTR. The Othorn is tuned quite a bit lower though and has more spl to lower frequencies as a result. So these 2 cabs are pretty similar in max output, one is a bit louder, one goes a bit lower.
So can we make a comparison of the JTR to the Keystone and TH118? Kind of but not as directly as I'd like.
Here's weltersys' quote on Keystone max spl - "As far as my readings outside, 105 dB at 32 meters would be 135 dB at one meter for the pair, about 129 dB per cabinet. From here - http://www.diyaudio.com/forums/subw...ng-18-15-12-inch-speakers-13.html#post2845286
The data-bass JTR max output measurement shows 127 db (not counting peaks) and it's taken at 2 meters distance, so +6 db for 1 meter equivalent = 133 db. The signal is a sine sweep of 24 second duration resulting in 3 db of compression at points in it's response.
Not sure what weltersys' measured signal was, how long it lasted, or how much compression resulted. But by these reports the Keystone is actually not too far off at 129 db vs 133 db.
We could compare sims of the Keystone (and/or the Xoc1 TH18) to the Othorn and get a different kind of comparison and then compare the sims to the Othorn/JTR data-bass measurements but I don't have time for that.
One question though, is the JTR drivers. Here's a picture of the Orbit Shifter Pro driver with claimed 30 mm xmax.
An externally hosted image should be here but it was not working when we last tested it.
And from a different angle.
An externally hosted image should be here but it was not working when we last tested it.
Is that a 30 mm driver? Probably not but it might be. Then there's this.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
That's another JTR driver with 19 mm claimed xmax. Does that surround look like it can support 19 mm xmax? I doubt it. And if that driver's claimed xmax isn't true then what about the Orbit Shifter driver's claimed 30 mm xmax?
These are nice drivers, no doubt about that. But the claimed xmax might be a bit exaggerated by the standards held by a company like B&C. Just for fun here's another JTR driver with 33 mm claimed xmax.
An externally hosted image should be here but it was not working when we last tested it.
I think JTR's claimed xmax ratings might be a little bit optimistic. Especially considering that the Orbit Shifter Pro isn't significantly louder than the Othorn which is not only tuned considerably lower but is also slightly smaller than the JTR. By calculated displacement alone, the JTR 18 inch driver with 30 mm xmax should have 20 - 25 percent more displacement than the Othorn driver so the Orbit Shifter Pro with it's higher displacement and higher tuning should kick the living snot out of the Othorn. And it doesn't.
Just some stuff to consider.
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I dont know about the declared 30mm xmax but from the CEA burst test I can say that sub can take a lot of power and keep going. When you see 140 dB at 40 hz really measured from a single 18, all doubts are minimized.
The DSL vs Xoc comparisson I made was in the clients club and I made it purely for study. I will take pictures and videos and put them there and in a few weekes I will make some outside tests (or a large 500sq meters room) with the DIY version and I will take sugestions of what to test.
The DSL vs Xoc comparisson I made was in the clients club and I made it purely for study. I will take pictures and videos and put them there and in a few weekes I will make some outside tests (or a large 500sq meters room) with the DIY version and I will take sugestions of what to test.
The keystone is 45" tall. Placing 2 keystones side by side is around 53 inches wide. That takes up a lot of space. Would it work if the cab width was increased to around say 40 inches, just wide enough to take 2 18 inch 18Sw115 speakers side by side?.... That is leaving the same size keystone exit nice and central to the drivers. That would work out good space wise. If the effect is equivalent to putting two cabs side by side, or doubling the power to one speaker in a normal keystone, then that would be great. Can you someone sim this.
Scientific,
1) It would work, but reducing the cabinet volume would decrease sensitivity, a bit less output per watt.
2) The exit size should need to be increased due to the increased cabinet volume and driver displacement. The driver's heat vents would be further from the Keystone exit, reducing thermal dissipation, increasing thermal compression.
3) The reduced frontal area would reduce forward directivity compared to the original design, another slight reduction in sensitivity.
4) You (or someone) could simulate the basic reduction in size (links to the Hornresp sims and discussions are in the OP) but the Keystone exit was designed empirically, using measured response variations until the optimal shape and exit size was arrived upon. Using Akabak (which I have not) changes in the exit shape might be more closely simulated.
Art
Art, I guess this would require some experimentation, especially to find the correct size exit as mentioned in your # 2) response. I wouldn't mind testing it but I'm only going to have one 18Sw115 driver in the short term so here goes... Placing 2 DSL TH118 cabs together has an area of 45 x 40, the same area as the wider Keystone cab I am suggesting. All I would want to achieve is similar SPL from 35 hz up to 80 Hz and mission accomplished.
The other points 1 & 3 make sense but I would hope the effects are negligible, although every db counts. I have tried Hornresp but not Akabak.
The other points 1 & 3 make sense but I would hope the effects are negligible, although every db counts. I have tried Hornresp but not Akabak.
Keystone Impedance
Keystone Impedance via DATS v2.
B & C 18SW115 - 4 ohm
One side panel not glued yet, only screwed together. Keystone panel without any bracing added (all other bracing is to spec). High-grade 18mm Birch Ply (heavy). The cabinet was made prior to the updated dimensions some time ago? -I believe Art mentioned there wouldn't be much difference in performance ?
Nice one Art !
Keystone Impedance via DATS v2.
B & C 18SW115 - 4 ohm
One side panel not glued yet, only screwed together. Keystone panel without any bracing added (all other bracing is to spec). High-grade 18mm Birch Ply (heavy). The cabinet was made prior to the updated dimensions some time ago? -I believe Art mentioned there wouldn't be much difference in performance ?
Nice one Art !
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I have now used my keystones with 8 ohm 18sw115 model on two nights of bass heavy techno music.
My long term limiter in the DRPA+ is set to 78 volt which should give the driver 936w if impedance minima is 6,5 ohm(not sure of this tho), the air coming from the vent holes are almost the same temperature as the room even after 6 hours of playing 3-5 dB into limiter
Could the air coming from the vent holes be significantly warmer than the room temperature without adventuring the drivers? If I change the limiter to the next setting it would yield 87,5v or 1177w for a 241w increase to the drivers. Would be nice with some feedback how hard you guys drive the 18sw115 thermally. Or if this would risk over excursion?
People are exalted on the sound to say the least
Here is a very bad iPhone video from last night if anyone is interested. https://www.dropbox.com/s/hnzyb7fch97witx/Tronik.mp4?dl=0
Thanks for great cabs Art!
My long term limiter in the DRPA+ is set to 78 volt which should give the driver 936w if impedance minima is 6,5 ohm(not sure of this tho), the air coming from the vent holes are almost the same temperature as the room even after 6 hours of playing 3-5 dB into limiter
Could the air coming from the vent holes be significantly warmer than the room temperature without adventuring the drivers? If I change the limiter to the next setting it would yield 87,5v or 1177w for a 241w increase to the drivers. Would be nice with some feedback how hard you guys drive the 18sw115 thermally. Or if this would risk over excursion?
People are exalted on the sound to say the least
Here is a very bad iPhone video from last night if anyone is interested. https://www.dropbox.com/s/hnzyb7fch97witx/Tronik.mp4?dl=0
Thanks for great cabs Art!
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You are welcome, Osse!
1) Sounds like you can drive them harder without thermal issues. Check the motor temperature too, once the magnet structure heats up the vent temperature will start to rise also.
2) Yes.
3) Pretty small increase in level. I was using about 3000 watt peak power with live music, and never had any thermal issues, though the guy I sold the Keystones to did burn one up shortly after the sale. I think he may have panned kick or bass to one side only, and tried to make up for the 6 db less output, driving the single cabinet into hard clip, increasing RMS level to above the thermal limit.
4) With a 30 Hz 24 dB BW HP in place, takes around 1500 Hz to hit Xmax, and about 6000 watts to hit Xmech. With most recorded music thermal, rather than mechanical would be the usual failure mode.
Art
How did you set up the DRPA+ to make it a long-term limiter?
Yes, but checking motor temps would probably be a more accurate method for checking safe temps. I use an IR thermometer. I found the area right next to the vent gets the hottest (hotter than the sides of the motor) on the exterior.
According to Bennett Prescott at B&C:
"The lowest temperature component is actually the glue that holds the magnet structure together. We end our power test when the outside of the magnet structure reaches 100° C, 212° F. The coil can take a lot more than that, but the magnet structure glue will begin to burn around 110°C. As long as you don’t let the motor get beyond 100°C you should be fine."
Yes, very bad - haha. Which iPhone is that? My 6s (and I believe the 5/5s) has some sort of hpf to prevent that insane distortion present in your video.
I believe he means "1500 *watts" not Hz.
Oh thanks for that info, and Art to.
I was just presuming that the limiter were long-term as I've seen peak limiters only in more expensive and newer units on the market.
The phone, I'm actually not sure as it was a friend of mines but she's an iphone kinda girl, when you say it I've seen much better recordings both visually and soundwise from iPhone so probably another brand.
The problem is that I have covered up the front with speaker cloth so it's easier to feel the air temp than the magnet temp, next gig I should get a thermometer to fasten on the magnet or make a small opening in the top so I can feel the magnet.
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I build 2 Keystones loaded with RCF LF18X451
Had to use MDF because there is funny enough no good wood available on the market here in Peru even though theres a rainforrest full of trees...
Tried to make a SIM in HornResp
I hope i did it wrong... Because that SIM looked like S...!
Huge peak at 35hz (105db)
Goes down in a U shape to around 47hz (84db)
And then up in another peak near 80hz (105db)
And then down to (84db) at 100hz
Anyways... Had a test with one of them the other day
Small room (5mX7m) a lot of bass cancellation in the middle of the room as you would expect in a rectangular room of that size, but really good closer to the corners.
Sounded really good in the low end for deep/heavy bass music
A bit muddy for more classic techno and house
Maybe its a question about to lowcut a bit higher around 40hz/50hz???
Gonna have a test with the 2 boxes next weekend in a party in a similar room of 5mX7m (also gonna do some measurements there)
Any idea of what would be the best position for optimal output/sound/less bass cancellation.
2 keystones together in 1 corner?
Or 1 in each corner?? or any other ideas???
Any inputs appreciated... And if someone is up for making a SIM with these drivers... Would as well be highly appreciated.
Had to use MDF because there is funny enough no good wood available on the market here in Peru even though theres a rainforrest full of trees...
Tried to make a SIM in HornResp
I hope i did it wrong... Because that SIM looked like S...!
Huge peak at 35hz (105db)
Goes down in a U shape to around 47hz (84db)
And then up in another peak near 80hz (105db)
And then down to (84db) at 100hz
Anyways... Had a test with one of them the other day
Small room (5mX7m) a lot of bass cancellation in the middle of the room as you would expect in a rectangular room of that size, but really good closer to the corners.
Sounded really good in the low end for deep/heavy bass music
A bit muddy for more classic techno and house
Maybe its a question about to lowcut a bit higher around 40hz/50hz???
Gonna have a test with the 2 boxes next weekend in a party in a similar room of 5mX7m (also gonna do some measurements there)
Any idea of what would be the best position for optimal output/sound/less bass cancellation.
2 keystones together in 1 corner?
Or 1 in each corner?? or any other ideas???
Any inputs appreciated... And if someone is up for making a SIM with these drivers... Would as well be highly appreciated.