.......and why your only viable option is either a large multiple driver sealed array or some form of vented alignment and if you don't go 'vertical', then ideally you'll still need baffles as large as the requisite horn mouths.
I've only auditioned some Avantgardes with active/EO'd sealed cabs that as a complete system didn't impress me overall, especially WRT the bottom end, so seemed but suited for 'girl and a guitar' music than full blown orchestras, organ symphonies; especially at ~ 'front row center seating' levels I demand, though I imagine their large, gorgeous, multiple driver bass horn would do them justice.
GM
Maybe try transmission line, much more linear as a function of input power and hardly ever go past 6 M/s air flow rate when designed correctly.
@DJK
So there are no exact plans for the PPSL as far as I read. I have to choose drivers and then see what comes up. My aim is reaching down from 30's to 160hz with good efficiency. I can have 2 cabs.
What would be the right woofers for PPSL. As I am in Turkey, I can find RCF woofers easier than others. Some B&C models as well as a few Fane ones. I can find Eminence but not neodymium ones.
What are the parameters to look for, shall I go for 15's or 18's for my needs? I want to choose drivers, get them and build one to hear for myself.
I think I can put plate amps on them and let my set deal with the rest of the system. I can have hypex 2.0 or 4.0 per ppsl bin.
So there are no exact plans for the PPSL as far as I read. I have to choose drivers and then see what comes up. My aim is reaching down from 30's to 160hz with good efficiency. I can have 2 cabs.
What would be the right woofers for PPSL. As I am in Turkey, I can find RCF woofers easier than others. Some B&C models as well as a few Fane ones. I can find Eminence but not neodymium ones.
What are the parameters to look for, shall I go for 15's or 18's for my needs? I want to choose drivers, get them and build one to hear for myself.
I think I can put plate amps on them and let my set deal with the rest of the system. I can have hypex 2.0 or 4.0 per ppsl bin.
There are plans and a cut list for the 35hz PPSL using the Eminence Kappa Pro 15 LF2.
http://i56.photobucket.com/albums/g196/dkleitsch/x-1.gif
Two and a half sheets of 3/4" will build two cabinets.
When using other drivers, the optimum Qts is 0.312 for the best combination of efficiency, box size, and bass extension. Fs of the driver is pretty much the cut-off point, you can go a bit lower as the air mass in the mounting plenum will lower the Fs a bit.
I'll have a look at the RCF drivers, they have some 18's that look very good, 27~28hz possible. Most of the B&C drivers don't go as low as the RCF.
http://i56.photobucket.com/albums/g196/dkleitsch/x-1.gif
Two and a half sheets of 3/4" will build two cabinets.
When using other drivers, the optimum Qts is 0.312 for the best combination of efficiency, box size, and bass extension. Fs of the driver is pretty much the cut-off point, you can go a bit lower as the air mass in the mounting plenum will lower the Fs a bit.
I'll have a look at the RCF drivers, they have some 18's that look very good, 27~28hz possible. Most of the B&C drivers don't go as low as the RCF.
I have converted to mm's, but I think i need to adjust differently. Do you think the port is ok, it seems narrow now. I think I have to take it to 65mm's and narrow the 230mm parts.
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Ok, on your cut sheet, I figured out the slot width.
It is B-(E+E+F+2.1") so 30.5-(9.125+9.125+7.5+2.1) = 2.65" = 67.31mm
I took 18mm as the mdf width. That is why I added 2.1". 18mm roughly makes 0.70"
I dont need to go high, so I decided to narrow the plenum down and make the slot 60mm wide. Is this ok?
It is B-(E+E+F+2.1") so 30.5-(9.125+9.125+7.5+2.1) = 2.65" = 67.31mm
I took 18mm as the mdf width. That is why I added 2.1". 18mm roughly makes 0.70"
I dont need to go high, so I decided to narrow the plenum down and make the slot 60mm wide. Is this ok?
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I don't know how to sim the ppsl. I only have hornresp and I don't know if this can be modelled there. Can anyone help me sim this with my dimensions?
Hi kodomo,
The link in Post #19 has a lot of good information, and other links on djk's PPSL.
I'll attach one way to simulate a generic PPSL done in Hornresp. The back chamber and ducts are just like a standard vented (bass reflex) enclosure. The plenum in which the drivers are mounted can only be approximated; I used OD (offset driver horn) for the driver arrangement: during the construction S1 can be reduced by blocking off the rear corners of the plenum, the drivers are centered @ S2 (you'll have to calculate how much cross-sectional area you have left over), @ S3 the plenum is past the drivers to its normal rectangular cross-section which remains to S4, and S4 to S5 is the rounding off (chamfering) of the plenum edge to the front face. Import the file into Hornresp, and change it for your application; you can also export an AkAbak script file from this (you'll have to set all flare rates to Con).
According to djk the big peak @ the top of the response band does not happen in reality, it's only due to the inability to simulate the drivers/plenum correctly (one driver inverted, and drivers moved as closely together as possible).
I suggest you read through the thread linked in Post #19.
Regards,
The link in Post #19 has a lot of good information, and other links on djk's PPSL.
I'll attach one way to simulate a generic PPSL done in Hornresp. The back chamber and ducts are just like a standard vented (bass reflex) enclosure. The plenum in which the drivers are mounted can only be approximated; I used OD (offset driver horn) for the driver arrangement: during the construction S1 can be reduced by blocking off the rear corners of the plenum, the drivers are centered @ S2 (you'll have to calculate how much cross-sectional area you have left over), @ S3 the plenum is past the drivers to its normal rectangular cross-section which remains to S4, and S4 to S5 is the rounding off (chamfering) of the plenum edge to the front face. Import the file into Hornresp, and change it for your application; you can also export an AkAbak script file from this (you'll have to set all flare rates to Con).
According to djk the big peak @ the top of the response band does not happen in reality, it's only due to the inability to simulate the drivers/plenum correctly (one driver inverted, and drivers moved as closely together as possible).
I suggest you read through the thread linked in Post #19.
Regards,
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Art Welter has done some real good measurement work on a dual 15 PPSL that he built.
While Hornresp shows peaking of up to 6~7dB at the top end of the band, his measured results were around 3dB at about 175hz.
I have made the plenum width as narrow as 5", but that requires a loading hatch on the bottom for mounting the drivers. My original prototypes were made this way, but with a 2-1/2" wide port on each cabinet side, and the overall dimensions being 18H x 36W x 30D.
The plan and cut list are for simple construction for PA build.
While Hornresp shows peaking of up to 6~7dB at the top end of the band, his measured results were around 3dB at about 175hz.
I have made the plenum width as narrow as 5", but that requires a loading hatch on the bottom for mounting the drivers. My original prototypes were made this way, but with a 2-1/2" wide port on each cabinet side, and the overall dimensions being 18H x 36W x 30D.
The plan and cut list are for simple construction for PA build.
If I didn't have the space for a Bass Horn I would look at multiple high efficiency 12, 15 or even 18 inch drivers in a line array.
I saw some 12" scanspeak drivers for subwoofer. Their fs is 17hz. They go to 38hz in a 46 litres sealed cabinet. If I have arrays of 5, it would work.
Why do you recommend the arrays? I am trying to understand different solutions 🙂
Why do you recommend the arrays? I am trying to understand different solutions 🙂
I got 2 ScanSpeak 30W/4558T00 over swap section of the forum. I am looking find two more, and I think 4x12" of these would be enough for one channel. I think 4 of them with a single hypex ds4.0 can cope with my proposed system without distorting.
Hmm, what you have is a great bass driver, but what you need to get 104 dB eff. from [4] drivers is a >98 dB/m mid-bass driver since the quantity must double for every 3 dB increase = [32]/channel for the 30W, so with only [4]/channel you'll need to either boost them or shelve down the horns 12 dB/channel to level match them + any extra for baffle step compensation [BSC].
So, is a 32:1 power differential [at minimum] acceptable to you? At a glance, it would seem to be since some highly regarded two way horn systems have at least this much once level matched, but if adding some -fb to the system isn't acceptable to keep cost, and more importantly, amp overall distortion down, then maybe not.
WRT the Hypex amp, the fact that its advertised as a sub amp combined with a max upper XO point limited to 120 Hz strongly implies to me that it's totally unsuitable for your 160 Hz upper limit BW requirements that need to be high SQ out to at least 320 Hz.
GM
So, is a 32:1 power differential [at minimum] acceptable to you? At a glance, it would seem to be since some highly regarded two way horn systems have at least this much once level matched, but if adding some -fb to the system isn't acceptable to keep cost, and more importantly, amp overall distortion down, then maybe not.
WRT the Hypex amp, the fact that its advertised as a sub amp combined with a max upper XO point limited to 120 Hz strongly implies to me that it's totally unsuitable for your 160 Hz upper limit BW requirements that need to be high SQ out to at least 320 Hz.
GM
I can boost the woofers. 32 to 1 is not a big problem. I listen to my current horn system which is as efficient as the one I am proposing with generally 0.5 watts to 1 watts, peaking sometimes (mostly because of bass) to 5 to 8 watts. (I have vu meter) 32x power differential would mean 1 watts is 32 watts per woofer, which is my general listening level. Even at 8 watts which rarely happen would mean 256 watts per woofer.
Yes, I have the hypex amp so i was hoping but it won't work. I can get 1600watt amp per array, or add 2 more per channel. Let me see which one is a better option price/performance.
Yes, I have the hypex amp so i was hoping but it won't work. I can get 1600watt amp per array, or add 2 more per channel. Let me see which one is a better option price/performance.
It seems if I have 6 woofers per channel, it would be a great match. It would excite the whole room evenly and without distortion as well.
Maybe after going all this way, I should get 12 woofers! I will first try these 2 to hear how they sound. If this is worth pursuing, I may go all the way and get all the woofers needed.
Maybe after going all this way, I should get 12 woofers! I will first try these 2 to hear how they sound. If this is worth pursuing, I may go all the way and get all the woofers needed.
Look at University Classic horn. More info here: https://community.klipsch.com/index...n-horn-profile-need-driver-choice-help/page-2
105dB 80Hz to 108dB at 500Hz:
But you can get 67Hz to 300Hz and about 108dB sensitive with 99dB 18in woofer.
Here is at xmax with a minor mod that I came up with:
105dB 80Hz to 108dB at 500Hz:
But you can get 67Hz to 300Hz and about 108dB sensitive with 99dB 18in woofer.
Here is at xmax with a minor mod that I came up with:
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Thank you very much xrk971. Yes, I checked these, as well as the 3 different Vitavox offerings online.
I decided not to have any folds in the sound path. I have a klipschorn and I am accustomed to folded path and its sound. I have my klipschorn crossed lower than stock units but still is at 350hz. I decided not have any fold over 80hz. It colours and veils the timbres of the instruments and even vocals to a degree. So I decided, firstly to try and not have any folds at all 🙂
I decided not to have any folds in the sound path. I have a klipschorn and I am accustomed to folded path and its sound. I have my klipschorn crossed lower than stock units but still is at 350hz. I decided not have any fold over 80hz. It colours and veils the timbres of the instruments and even vocals to a degree. So I decided, firstly to try and not have any folds at all 🙂
I got 8 of 30w4558T00 scanspeak woofers. I will have them in arrays of 4. Each will be sealed. So it is like having 8 sealed bass speakers. I have calculated that if they each have 50liters sealed box, they will work down to 38hz.
Now, these are 4ohms each. So theoretically each array if wired in series (with 4 woofers) will be 16ohm.
I think I need a 2channel power amp that can pump 400watts at 16 ohms to each channel.
Am I right? If I am, what amps would you suggest?
For the rest of my system, the efficiency is very high (107db/1w), so I have a set amp running 845, 300b and 310a's.
Now, these are 4ohms each. So theoretically each array if wired in series (with 4 woofers) will be 16ohm.
I think I need a 2channel power amp that can pump 400watts at 16 ohms to each channel.
Am I right? If I am, what amps would you suggest?
For the rest of my system, the efficiency is very high (107db/1w), so I have a set amp running 845, 300b and 310a's.
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