Hi Rudolf:
Rooms at RMAF are mostly quite small hotel rooms...at Munich High End we have a 30x30x4m space to play in.
Yeah baby!! Bring on the BIG STUFF!! WOOF WOOF!
Who let the dogs out? Hoooo! Hoooo!
The problem is that the showroom doors are not big enough. We had to cut the WE horns a new joint so they will fit through.
Original 1930s WE LF baffles are also open type...but there we are talking 300-400kg and absurd dimensions. This "Slot OB" provides a nice portable solution, even with a pair of 15s and a pair of 30 inchers.
Hope you can come by and join the listening party!
Rooms at RMAF are mostly quite small hotel rooms...at Munich High End we have a 30x30x4m space to play in.
Yeah baby!! Bring on the BIG STUFF!! WOOF WOOF!
Who let the dogs out? Hoooo! Hoooo!
The problem is that the showroom doors are not big enough. We had to cut the WE horns a new joint so they will fit through.
Original 1930s WE LF baffles are also open type...but there we are talking 300-400kg and absurd dimensions. This "Slot OB" provides a nice portable solution, even with a pair of 15s and a pair of 30 inchers.
Hope you can come by and join the listening party!
ahh, joe told me about this... i have read through all the posts. it was a pleasant surprise for me that nelson worked for amt and heil. a lot of good info in these forums, although it is hard for me to put up with the ruts. i also have a kid and no time for it! i came at this project through thomas dunker, who had played around with these types of baffles a great deal, more than a decade ago. it is not new to me. nor are line arrays and ribbons, both of which i have built (with dick sequerra). i have read the heil patents also. i am not going to get too mixed up in the controversy, although i should say that i made this sub precisely for the same reasons nelson did his. but he is a braver man than i, working with lowthers! i hate those pieces of crap. never again. never. i do appreciate he is driving them with a high output Z which is of course the only way. well, eq... i am getting off track. if you are working with a large room, but not so large that you can fit an actual bass horn (and not a one eighth length folded corner floor compromise, which is too variable and weird for every room) than you will eventually get around to looking at this design.
at last year's munich show, we built a pp isobaric sub with 4 altec 515Bs in a EBS alignment. it was paired with a WE16B and played to a space almost appropriate with a horn that size (we should have had two horns in my opinion...). the sub works very well except in a really large space. omni bass is a problem in a really large space. tom danley's remarks are well taken about arena sound. at munich, the bass collected in the corners and peaked and nulled throughout the room. of course.
this year, we are bringing a pair of WE15As, which will play the hell out of that room. but for bass, i wanted to improve the fit. i want the bass to be out in the middle where the people are, and not in the corners where they aren't. OB sub was first on the list. the WE15A plays down to 80Hz (and up to 8KHz) and we don't want the bass to mix with the mids of the horn at all. so the xover cuts at 18dB/oct. 50-60Hz (depending on the room).
the other problem is efficiency. when dealing with large spaces, it's an issue. especially with tube amps. we use 6 to 30 watt amps (300B, DA100 and 4242C). the EV 30W is perverse and not even a great bass speaker for modern sensibilities. neither is the altec 515B. they have the same problem. Xmax is only 4mm and the Vas means ported boxes are about the size of a van. but they have a very low Fs, which can be lowered in a chambered OB, and the filter (the slot is bandpass) can be optimized for the first 2 octaves. we don't want or need ANY mid to come out of the slot, so that should take care of any controversy. the chamber raises the extremely low Qts (0.17) to a perfect 0.6. there is no box resonance. there is no box. the crossover is electronic... and the amp is directly connected to the speaker.
the end result is a good match to the horns... in the large space we used to test it, it did exactly what was required. deep natural bass, without any boom, out in the middle of the room. the 4 drivers are all in parallel, and the efficiency at low frequencies is reasonable. 30 watts will safely drive KEF (and whoever else is next to us) insane. but it is better to have it in reserve. at least we play actual records.... music. and not audiophilia.
some of you may be wondering why there are 2 different sized woofers... it is an attempt to get the entire driver closer to the floor. Xmax and efficiency of the 2 is almost identical. i am not worried about chamber resonances outside of the bandpass... they are filtered out electronically.
jc morrison
at last year's munich show, we built a pp isobaric sub with 4 altec 515Bs in a EBS alignment. it was paired with a WE16B and played to a space almost appropriate with a horn that size (we should have had two horns in my opinion...). the sub works very well except in a really large space. omni bass is a problem in a really large space. tom danley's remarks are well taken about arena sound. at munich, the bass collected in the corners and peaked and nulled throughout the room. of course.
this year, we are bringing a pair of WE15As, which will play the hell out of that room. but for bass, i wanted to improve the fit. i want the bass to be out in the middle where the people are, and not in the corners where they aren't. OB sub was first on the list. the WE15A plays down to 80Hz (and up to 8KHz) and we don't want the bass to mix with the mids of the horn at all. so the xover cuts at 18dB/oct. 50-60Hz (depending on the room).
the other problem is efficiency. when dealing with large spaces, it's an issue. especially with tube amps. we use 6 to 30 watt amps (300B, DA100 and 4242C). the EV 30W is perverse and not even a great bass speaker for modern sensibilities. neither is the altec 515B. they have the same problem. Xmax is only 4mm and the Vas means ported boxes are about the size of a van. but they have a very low Fs, which can be lowered in a chambered OB, and the filter (the slot is bandpass) can be optimized for the first 2 octaves. we don't want or need ANY mid to come out of the slot, so that should take care of any controversy. the chamber raises the extremely low Qts (0.17) to a perfect 0.6. there is no box resonance. there is no box. the crossover is electronic... and the amp is directly connected to the speaker.
the end result is a good match to the horns... in the large space we used to test it, it did exactly what was required. deep natural bass, without any boom, out in the middle of the room. the 4 drivers are all in parallel, and the efficiency at low frequencies is reasonable. 30 watts will safely drive KEF (and whoever else is next to us) insane. but it is better to have it in reserve. at least we play actual records.... music. and not audiophilia.
some of you may be wondering why there are 2 different sized woofers... it is an attempt to get the entire driver closer to the floor. Xmax and efficiency of the 2 is almost identical. i am not worried about chamber resonances outside of the bandpass... they are filtered out electronically.
jc morrison
some interesting info which may apply to this thread...
There is some interesting info at this link for restricted throat horns which may apply to the slot woofer...
<meta name="description" content="Klipsch audio systems provide the true audio/video lover a wide variety of high performance loudspeakers and loudspeaker systems for music and home theater entertainment centers, including iPod speakers, multimedia s
If the front and rear had a restricted slot would that not address the issue of the imbalance front and rearwards if the area of the ports front and back were symmetric maybe having 8 woofers like the white unit shown a few pages back but maybe with the top 4 compressing with the lower 4 expanding but venting on the opposite side so effectively creating a bass pulse in the same direction to the other 4 woofers.
It is similar to the new Orion style woofer section but rotated 90 degrees.
I have a design in my minds eye
There is some interesting info at this link for restricted throat horns which may apply to the slot woofer...
<meta name="description" content="Klipsch audio systems provide the true audio/video lover a wide variety of high performance loudspeakers and loudspeaker systems for music and home theater entertainment centers, including iPod speakers, multimedia s
If the front and rear had a restricted slot would that not address the issue of the imbalance front and rearwards if the area of the ports front and back were symmetric maybe having 8 woofers like the white unit shown a few pages back but maybe with the top 4 compressing with the lower 4 expanding but venting on the opposite side so effectively creating a bass pulse in the same direction to the other 4 woofers.
It is similar to the new Orion style woofer section but rotated 90 degrees.
I have a design in my minds eye
Driver Mounting
Must the drivers need to be flush mounted to their baffles inside the slot area? Would flush mounting the drivers reduce turbulance inside the slot?
Are the woofer pairs seperated by a "brace" that is formed by layering the sheets of plywood? See attached diagram. From the photos describing the project, it appears that a "horse shoe" structure is formed inside the slot.
See pics.
Thanks,
Vince
Must the drivers need to be flush mounted to their baffles inside the slot area? Would flush mounting the drivers reduce turbulance inside the slot?
Are the woofer pairs seperated by a "brace" that is formed by layering the sheets of plywood? See attached diagram. From the photos describing the project, it appears that a "horse shoe" structure is formed inside the slot.
See pics.
Thanks,
Vince
Attachments
so what
This is all fine a dandy. Unfortunately, I don't have the time or energy to screw around with this should I or shouldn't I do it. What about the neat two way NP uses to test his creations that we all see on his website? I probably missed it since I spend most of my meaningless life teaching and the rest getting laid and listening to music.
This is all fine a dandy. Unfortunately, I don't have the time or energy to screw around with this should I or shouldn't I do it. What about the neat two way NP uses to test his creations that we all see on his website? I probably missed it since I spend most of my meaningless life teaching and the rest getting laid and listening to music.
Anyone? anyone?
Anyone else build this speaker? Anyone else move from physics theory to pratice? If you built a full-scale model, please share your photos and sound impressions. Don't let the last 40 or so pages of arguments disturb you. It's just necessary growing pains.
I'll start. It sounds really good. Lots of appropriate bass without the box sound. I guess at first I was waiting for it to impart bass in every part of a song whether is needed it or not, but that would be like some people buying a sub for a home theater and they are not happy unless they hear their sub through out the whole movie. Once I got over that need to hear the bass in a pronounced manner, I began to appreciate what it could do. I did throw on some Hooverphonic to check out how low would it go...and it did.
BTW- hard rock is pretty insane on this speaker. More than I need at close range.
It does blend well with the 6.5" full-range (FR) driver, although I haven't completely dialed in the levels perfectly yet. I'm using a volt meter in the active crossover and adjusting it from there. I bumped up the Q at the crossover to .9 and like it. The bass leaves off at 100hz and have set the FR to pick at around 125Hz. I'm still playing with the XO points; I only make changes once at night.
My issues are not with the bass unit, it's with the FR driver (Parts Express PS180-8). At first listening session, there was much midrange emphasis. It really takes away from the rest of the system. It's horrible actually. It was better on night two. I suspect there will be a long break-in period. So far I've heard it takes 100-200 hours for drivers to relax.
I have not used baffle step compensation, but read a nice article at Elliot Sound. it would not be difficult to implement a line level ciruit betweem the XO and amp.
The FR is powered by the Zen 9 and bass unit by the F5 modified with no thermistor and not protection. The woofers are Peerless India 8", 12 ohm, shielded drivers. They are wired 3 in series, then the set is in parallel.
One more thing...I mounted the woofers on the outside baffles. The slots are probably a bit larger than they should be, but I don't hear a problem. There is no port noise. The tones out of the slots are clear and defined.
Your turn...
Vince
Anyone else build this speaker? Anyone else move from physics theory to pratice? If you built a full-scale model, please share your photos and sound impressions. Don't let the last 40 or so pages of arguments disturb you. It's just necessary growing pains.
I'll start. It sounds really good. Lots of appropriate bass without the box sound. I guess at first I was waiting for it to impart bass in every part of a song whether is needed it or not, but that would be like some people buying a sub for a home theater and they are not happy unless they hear their sub through out the whole movie. Once I got over that need to hear the bass in a pronounced manner, I began to appreciate what it could do. I did throw on some Hooverphonic to check out how low would it go...and it did.
BTW- hard rock is pretty insane on this speaker. More than I need at close range.
It does blend well with the 6.5" full-range (FR) driver, although I haven't completely dialed in the levels perfectly yet. I'm using a volt meter in the active crossover and adjusting it from there. I bumped up the Q at the crossover to .9 and like it. The bass leaves off at 100hz and have set the FR to pick at around 125Hz. I'm still playing with the XO points; I only make changes once at night.
My issues are not with the bass unit, it's with the FR driver (Parts Express PS180-8). At first listening session, there was much midrange emphasis. It really takes away from the rest of the system. It's horrible actually. It was better on night two. I suspect there will be a long break-in period. So far I've heard it takes 100-200 hours for drivers to relax.
I have not used baffle step compensation, but read a nice article at Elliot Sound. it would not be difficult to implement a line level ciruit betweem the XO and amp.
The FR is powered by the Zen 9 and bass unit by the F5 modified with no thermistor and not protection. The woofers are Peerless India 8", 12 ohm, shielded drivers. They are wired 3 in series, then the set is in parallel.
One more thing...I mounted the woofers on the outside baffles. The slots are probably a bit larger than they should be, but I don't hear a problem. There is no port noise. The tones out of the slots are clear and defined.
Your turn...
Vince
Last edited:
Thanks for the update Vince. I have been waiting for your report since you stated that you were going to try this. I've been looking at budget drivers from several sources, including the Peerless that you used.
Do you have the capability of running a frequency sweep? I would be interested in knowing how low these things go. I am planning to use a similar set-up under some vintage 12" co-axial's I bought to experiment with. ( so far I have University Mustangs, Coral, Pioneer, and EV's, still looking for a deal on some Jensens. All are from the '60's and early '70's. )
I'm going to go a little more ghetto on my set up, basic plate amp with 2nd order XO, and my KT-88 SET amp on top.
I'm also thinking about "U" frame enclosures to reduce the monster baffle size....
keep up with the update's please.
PS: If those PE fullrangers are anything like the Fostex FE206's I have, they will take a lot of hours to break in, but will get better, and smoother as they do. When I broke in mine, I built an OB about 18" wide, by 40" tall, with the thought that later I could add wings, or a shallow "U" frame, and a couple of 12" woofers, but I have them in some back loaded horns now that I really like.
John
Do you have the capability of running a frequency sweep? I would be interested in knowing how low these things go. I am planning to use a similar set-up under some vintage 12" co-axial's I bought to experiment with. ( so far I have University Mustangs, Coral, Pioneer, and EV's, still looking for a deal on some Jensens. All are from the '60's and early '70's. )
I'm going to go a little more ghetto on my set up, basic plate amp with 2nd order XO, and my KT-88 SET amp on top.
I'm also thinking about "U" frame enclosures to reduce the monster baffle size....
keep up with the update's please.
PS: If those PE fullrangers are anything like the Fostex FE206's I have, they will take a lot of hours to break in, but will get better, and smoother as they do. When I broke in mine, I built an OB about 18" wide, by 40" tall, with the thought that later I could add wings, or a shallow "U" frame, and a couple of 12" woofers, but I have them in some back loaded horns now that I really like.
John
Hi John,
Some of those older FR drivers are well respected. I've seen some field coil drivers on eBay. I wonder how they would compare to today's field coil speakers? At $5k, I'll never know.
I don't have the proper equipment to run a sweep.
I have an old tube freq generator that I have never turned on.
Not sure it works.
I don't have a lab mic either, although Parts-Express has one on sale right now...
I do have the Woofer Tester III, it does a freq sweep to grab speaker parameters. Not sure if that would tell us anything, but it would be fun to try. Would definately tell us what's going on with impedance and phase.
I have a few test CDs with tones and a Radio Shack SPL meter.
Also have a laptop with a freq generator. Maybe this would be enough to get an idea of what it's doing? Do you have any suggestions on setup?
Close mic'ing or at 1 meter? I have to say, it would be a pain to drag all the gear and speakers outside the house. It's heavy and awkward to move around.
Let me know what suggestions you have and I'll give it a shot Thursday night.
Regarding the PE FR drivers- from what I read at PE, it seems they were modeled after the Tang Band FR drivers ($250). The contributor said, "PE has come close to recreating the Tang Band FR drivers".
Vince
Some of those older FR drivers are well respected. I've seen some field coil drivers on eBay. I wonder how they would compare to today's field coil speakers? At $5k, I'll never know.
I don't have the proper equipment to run a sweep.
I have an old tube freq generator that I have never turned on.
Not sure it works.
I don't have a lab mic either, although Parts-Express has one on sale right now...
I do have the Woofer Tester III, it does a freq sweep to grab speaker parameters. Not sure if that would tell us anything, but it would be fun to try. Would definately tell us what's going on with impedance and phase.
I have a few test CDs with tones and a Radio Shack SPL meter.
Also have a laptop with a freq generator. Maybe this would be enough to get an idea of what it's doing? Do you have any suggestions on setup?
Close mic'ing or at 1 meter? I have to say, it would be a pain to drag all the gear and speakers outside the house. It's heavy and awkward to move around.
Let me know what suggestions you have and I'll give it a shot Thursday night.
Regarding the PE FR drivers- from what I read at PE, it seems they were modeled after the Tang Band FR drivers ($250). The contributor said, "PE has come close to recreating the Tang Band FR drivers".
Vince
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.