hi td
a lr filter has a -6db/oct at x-over point.
extended basshelf tuned to 30 (with processing) -3 wil be at 27 hz.
looking at the graph me thinks its tuned to 34 or so(so lower then my earlier post
)so with processing gives you a nice -3 at 30 or so.
Thanks for the info. I'm a skeptic on those excursion claims though. Specifically the 4" p2p xmech. I have never used a driver that had that much stroke capability that is anywhere near as shallow as this one. I don't see how there could be enough clearance below the spider between the triple joint and top plate. The surround is also a question mark. It may be a 4 roll but it appears from the pics to be not very wide and the creases look shallow. Agree with Dan this seems like a waste of Neo as you can make a nasty motor with less than half of the volume that they have there.
EDIT: 17 lbs weight for this driver and a total depth of 7.88"
Last edited:
The PK Sound CX800 spec sheet does not specify filter type, or "processing" used other than top and bottom filter points.hi td
a lr filter has a -6db/oct at x-over point.
extended basshelf tuned to 30 (with processing) -3 wil be at 27 hz.
looking at the graph me thinks its tuned to 34 or so(so lower then my earlier post
so with processing gives you a nice -3 at 30 or so.
A BW 24 is -3 dB at the crossover point, often used for cabinets that already roll off acoustically at around 24 dB per octave to not loose output near Fb.
All processors are not equal, unfortunately the "same" filter on different units often does not result in the same acoustical result, even different platforms by the same manufacturer have varying results.
With only a idealized fat blue line humping up toward the bottom on the spec sheet to go by, I'd guess the PK Sound CX800 Fb even a few Hz higher than your 34 Hz estimate.
At any rate, good long throw speakers in a (relatively) low tuned bass reflex, output level rated at an unspecified frequency, ho hum...
Art
"EDIT: 17 lbs weight for this driver and a total depth of 7.88" "
I agree, that's just one of the things that doesn't add up.
**********************************************
Hi Dennis,
We are awaiting more metal parts at the moment due to backorders, so I will get to the measurements as son as they come in. Probably sometime next week.
I am sorry for the delay. We are currently out of stock so the pictures will be forthcoming as well.
Best Regards,
Mark Pinske
I agree, that's just one of the things that doesn't add up.
**********************************************
Hi Dennis,
We are awaiting more metal parts at the moment due to backorders, so I will get to the measurements as son as they come in. Probably sometime next week.
I am sorry for the delay. We are currently out of stock so the pictures will be forthcoming as well.
Best Regards,
Mark Pinske
Last edited:
hi art
somehow it got in to my head it was a rl x-over
.we agree the fb is higher then 30
.
Meh...
For a semi-traditional sub design I'd look at the Martin MLX
MLA? Multi-cellular Loudspeaker Array. Martin Audio Ltd.
-Matt
PS:Let the record show that at least once I have not suggested Danley =P
Bassnectar had switched to DB last I checked. It's true though that many dubstep artists/listeners are in to the PK stuff. I think it's because the music(not all of it) and the sound system have something in common, they are both loud and obnoxious.
For a semi-traditional sub design I'd look at the Martin MLX
MLA? Multi-cellular Loudspeaker Array. Martin Audio Ltd.
-Matt
PS:Let the record show that at least once I have not suggested Danley =P
I took a stab at making something louder.
Details are here:
Louder than a PK Sound CX 800 - DIYMA Car Audio Forum
Also, in my previous sims of the CX800 I was a bit too generous with the box size, and a bit too small on the vent size. Using the drawings from the PDF, I corrected that in the new thread.
Due to the smaller box size and larger vent, the output at the tuning frequency is quite a bit peakier.
Of course, they may fix this via EQ in the powered box.
Details are here:
Louder than a PK Sound CX 800 - DIYMA Car Audio Forum
Also, in my previous sims of the CX800 I was a bit too generous with the box size, and a bit too small on the vent size. Using the drawings from the PDF, I corrected that in the new thread.
Due to the smaller box size and larger vent, the output at the tuning frequency is quite a bit peakier.
Of course, they may fix this via EQ in the powered box.
Possibly. The show I attended of his had L'acoustic, so... They had a lot of em - over 30 dual 18" cabs, IIRC.
Which leads me to my next question: how many cabs does PK typically bring to these shows. There's another insane-bass company in the UK, but they have 9 dual 18" cabs per side - that many of almost anything would be pretty insane. Just sayin.
Art, how do you go about your "max output" tests? And do ya kinda gotta be prepared to lose a driver in the process? Heh..
Last edited:
"Max output" could only be determined by destruction of the driver either thermally or mechanically, not something I have the budget or amplification to do regularly, though mistakes have happened.
I have looked at output levels with music and pink noise on several of my cabinets, but have never been very interested in "max output", more interested in maximum clean output.
To determine distortion, I use sine waves at various frequencies and look at the harmonic output using Smaart's RTA. Since sine waves contain twice the average power of the AES pink noise that most drivers are rated for, the tests must be short, and enough time between test tones so that heat does not build up.
Anyway, I don't know why Patrick revived this thread, PK's specifications give no real data about how loud they are at any given frequency, then he compares a simulation of a cabinet that could not physically be transported to it.
Seems as goofy as the name of this thread, the PK Sound CX800 amplifier is 95% efficient, but the cabinet is a typical bass reflex, no more efficient than any other BR of similar size and tuning.
It gets loud simply because the drivers used have good Xmax potential and a voice coil that can handle the power required to push them to Xmax.
Art
What's the point of my simulations?
The point of my simulations is to create a level of bass that no ones ever heard.
https://www.youtube.com/watch?v=xU1GrWWGo3I
The video in the link above shows Excision's 'Executioner' stage. It's hard to tell from the video, but the 'Executioner' set basically consists of the following:
1) A big set made of wood and drywall
2) A projector in the back of the room, that throws a 300" video onto the set
3) a DJ, 'Excision', with a laptop. (Obviously no one plays records any more. If I was really cynical I might point out that half the kids would have no idea if that was really Excision up on stage. Taken to the extreme, you'd wear a mask, like 'Deadmau5' or 'Daft Punk' or 'The Knife')
4) a big pile of PK Sound CX 800 subs on either side of the stage.
An externally hosted image should be here but it was not working when we last tested it.
The flyer lists the speakers and the watts. How many rock shows do this? The EDM crowd *really* cares about bass.
An externally hosted image should be here but it was not working when we last tested it.
As shown in the pics above, the stage sets are becoming a pretty important part of the EDM experience. I'm offering up a subwoofer design that becomes part of the stage, which basically leverages the size of the stage itself to increase efficiency.
YES, it would take an hour to assemble, but these are not small stages any longer. If I'm not mistaken, Electric Daisy Carnival was the biggest concert in the world last year, bigger than U2
Simulations don't create bass, cabinets do.
Comparing a simulation using four 21" in a bass horn that ideally would use 27 pieces of plywood to a moderately sized dual 18" (17.7 cubic foot net) bass reflex cabinet one would expect the quad 21" would have a bit more output
.Duh.
The main idea is that these guys are building a stage anyways. So if you're already building a stage, and your audience is a bunch of bass heads, why not make the stage a subwoofer?
https://www.youtube.com/watch?v=tloy0ldDvVQ
Jump to 0:25 in the video, and you'll see that they've already got a big ol' wall. Adding some subs to the wall is easy/efficient/novel.
It's a real live version of the amplifier in Back to the Future
Or an homage to Richard Clark
As for your question, about size versus output, the answer is simple. Just keep adding drivers.
For instance, with one driver the 'horn' depth is 3/4". With eight drivers, the depth is 6". These wavelengths are insanely long, so it's easy to add lots of subwoofers without running into cancellation problems. Should be easy to go up to sixteen 21" woofers if you had the budget.
Funny this post is about PK sound, as Patrick posted about Excision up there^. I just was at an Excision concert last weekend. The bass was intense. I believe there were 24 CX800's the tour brought, plus 12 Nexo CD18's that congress theater has. [just for the bass of course] There were 2 sets of 12+ line array speakers on each side I have a video where you can see them but my phone is dead. Now I didn't look too much into these subs, but are they short throw..? because I was right in front when Excision came on and the bass was stunning. Then later on I went to the back and the bass was not impressive at all. When I last went for, 12th Planet, and before that, Knife Party, just the 12 Nexo's would still pound your chest from the back.
I walked around the club a bit until I found a spot with a standing wave. The pressure was intense enough to push the air out of your lungs. Above me I could see that all the air being pushed by the speaker cones was 'dusting' the Exit sign. As in it was literally blowing off a decades worth of grime that had accumulated on top of the sign. (Who needs a dustbuster when you have a pile of CX800s?)
When I moved five feet away from that spot, the bass disappeared, likely because peaks in the room response tend to be right next to nulls, particularly near the edges of the room.
Also, sounds like we've seen a lot of the same tours!
Have seen Knife Party, 12th Planet, Skrillex (twice), Excision and Kill the Noise. All since I discovered the wonders of 30hz bass w/kilowatts amps
gota love that deep bass. When we were walking to congress theater, we heard the bass from down the street, and they didn't even have it turned up yet. I saw Kill The Noise too, he was with Knife Party. I've been going to a lot of EDM concerts... I could list tons of DJ's xD but the most bass is deff of the Dubstep/Trap concerts. but the most rage/hype is at the Electro House ones, like Steve Aoki. I'm going to EDC Chicago, it's the first one they are doing in the mid west! I can't wait to see the setup they do, and how many speakers they use!
Some reasons not to make the "stage" a subwoofer:
1. Few performers would prefer being the focal point for all the bass
2. The flat subwoofer would present a sizable unsafe wind load
3. A giant subwoofer is not scaleable for smaller venues
4. A single subwoofer is not steerable
5. Video walls are being used as backdrops
6. Additional set up time with no sonic advantage cuts tour profits
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.