freddi said:
I was amazed to see very little cone movement. My amplifier is only 10 watts or so. Perhaps more wattage would get the cones excited.
The efficiency is excellent, so high wattage isn't an absolute requirement. I get plenty of volume.
As far as drums go, I'm enjoying a CD entitled "Passion" subtitled "A Passion Remembered". 1995 Unison Music Produced and arranged by Mark Baldwin and Eric Darken. Excellent music.
Yup, all those cones = clean sound.
Jbl had in their papers that as you double the drivers, at the same volume level the excursion is halved, and the distortion is reduced to 1/4.
Excursion is about frequency + box controlling a woofer + spl
No box = bad to limit excursion
but bunchs of drivers = hardly any excursion
Going from 10 watts to 100 may pick up about 10db.
If your amp sounds good to you, I wouldn't bother.
People love that tweeter
http://www.jblproservice.com/pdf/Theatre Series/46120K.pdf
http://www.jblpro.com/pub/obsolete/4612ok.pdf
Crossing high works well to offset lack of hf lift in a cd horn.
But the z-peak plays with stuff too.
Manufacturors do the same thing.
Neat project.
Norman
It takes some doing to get it right.
Jbl had in their papers that as you double the drivers, at the same volume level the excursion is halved, and the distortion is reduced to 1/4.
Excursion is about frequency + box controlling a woofer + spl
No box = bad to limit excursion
but bunchs of drivers = hardly any excursion
Going from 10 watts to 100 may pick up about 10db.
If your amp sounds good to you, I wouldn't bother.
People love that tweeter
http://www.jblproservice.com/pdf/Theatre Series/46120K.pdf
http://www.jblpro.com/pub/obsolete/4612ok.pdf
Crossing high works well to offset lack of hf lift in a cd horn.
But the z-peak plays with stuff too.
Manufacturors do the same thing.
Neat project.
Norman
It takes some doing to get it right.
neat, looks similar to the jbl dual 8" plus baby cheek except that's an mtm. Those tweeters are super stupid expensive (2404). Just saw a new pair for sale for $900 on http://www.canuckaudiomart.com/details/105257-jbl_2404h_babycheek_tweeters__new/
even used I think they run $500.
I just say an add on craig's list for $75 each (probably needing new diaphrams).
Yea, I like 15's.
The bass feels right compared to 1 or 2 12's even at low volume.
I remember hearing the sunfire 8" sub.
Yea it goes deep, but hey, it only an 8".
It didn't move the air very well.
It's not a db thing, more of an air pressure.
But that is the whole pressure wave versus velocity wave of sound (a huge can of worms).
Like a w-bin bass horn I had, no bass, till you got about 15 feet away, or you got pounded down the hallway.
Yea, we have a diy crowd here near Iowa city, but you need a dense population to offset $$$. Diy is typically low cost until people are willing to pay 5 times the price for a driver to get that 10% improvement in sound quality. Or the guy does woodwork and would rather build something than pay full retail.
I can't even get the 2 people who are into the stuff at work to come over to hear my setup (that sometimes changes weekly).
The diyIowa is neat but I don't need to hear another cone and dome 6.5" 2 way. But some drivers work well.
I'm just lucky I have a smart audio friend (ex pa) but I play with full range stuff that doesn't interest him. He had his own 24db LR crossovers for big pa's and car audio (using klipschorn parts) in vehicles b4 there was the stuff. I'm a "transparancy guy" wanting minimal components in the audio path from amp to speaker.
We diyers are a small slice of audio, and even then we split apart over what we all feel is important.
There are many roads to audio nirvana.
Norman
even used I think they run $500.
I just say an add on craig's list for $75 each (probably needing new diaphrams).
Yea, I like 15's.
The bass feels right compared to 1 or 2 12's even at low volume.
I remember hearing the sunfire 8" sub.
Yea it goes deep, but hey, it only an 8".
It didn't move the air very well.
It's not a db thing, more of an air pressure.
But that is the whole pressure wave versus velocity wave of sound (a huge can of worms).
Like a w-bin bass horn I had, no bass, till you got about 15 feet away, or you got pounded down the hallway.
Yea, we have a diy crowd here near Iowa city, but you need a dense population to offset $$$. Diy is typically low cost until people are willing to pay 5 times the price for a driver to get that 10% improvement in sound quality. Or the guy does woodwork and would rather build something than pay full retail.
I can't even get the 2 people who are into the stuff at work to come over to hear my setup (that sometimes changes weekly).
The diyIowa is neat but I don't need to hear another cone and dome 6.5" 2 way. But some drivers work well.
I'm just lucky I have a smart audio friend (ex pa) but I play with full range stuff that doesn't interest him. He had his own 24db LR crossovers for big pa's and car audio (using klipschorn parts) in vehicles b4 there was the stuff. I'm a "transparancy guy" wanting minimal components in the audio path from amp to speaker.
We diyers are a small slice of audio, and even then we split apart over what we all feel is important.
There are many roads to audio nirvana.
Norman
I had no idea the 2404s were so valuable. I'll have to treat mine with extra care.
The MTM is actually a center channel sitting on end (sorry for the misleading photo). It's loaded with 2118s.
The bass reflex cab is loaded with 2240s. They're great for low wattage amplifiers.
Dual bass and midrange SPL 100db 1W1M. Still gets trounced by the horn, though. But, then again, my hearing's weak on the top end, so I like the added brilliance.
Here's a pic of the paper-mache horns I have in my primary system. They're 33" tractrix loaded with a JBL 2445:
The MTM is actually a center channel sitting on end (sorry for the misleading photo). It's loaded with 2118s.
The bass reflex cab is loaded with 2240s. They're great for low wattage amplifiers.
Dual bass and midrange SPL 100db 1W1M. Still gets trounced by the horn, though. But, then again, my hearing's weak on the top end, so I like the added brilliance.
Here's a pic of the paper-mache horns I have in my primary system. They're 33" tractrix loaded with a JBL 2445:
Attachments
neat stuff.
I've played with the jbl 2447 on the as2222 (cross 24db at 1.2khz).
I got an altec 291-16a that works well on a mcm bowtie horn crossed at 1khz.
I also heard my 291 on an ev hr90 horn.
I've also played with dh1a on ev hp 940 and hp640 horns.
Neat horn.
I was looking at the shperical tractrix on ebay.
Any parallel surfaces in horns = bad.
Glare or zing, whatever it is, something that's not right.
That little jbl horn of yours is probably 107db 1w/1m.
The replacement diaphram is probably $100 not including installation.
Norman
I've played with the jbl 2447 on the as2222 (cross 24db at 1.2khz).
I got an altec 291-16a that works well on a mcm bowtie horn crossed at 1khz.
I also heard my 291 on an ev hr90 horn.
I've also played with dh1a on ev hp 940 and hp640 horns.
Neat horn.
I was looking at the shperical tractrix on ebay.
Any parallel surfaces in horns = bad.
Glare or zing, whatever it is, something that's not right.
That little jbl horn of yours is probably 107db 1w/1m.
The replacement diaphram is probably $100 not including installation.
Norman
So I just bought a bunch (20) of 5.25" Peerless "India" FR drivers from PE for real real cheap. I think I'll try to emulate the line array here, though I may go u-baffle all up and down instead of big wings at the bottom and flat OB on top. Not that I know much about u-baffles. I have a simple 10" sealed sub to back 'em up down low, and I picked up some appropriately cheap piezos to roll in up high (I've heard these can be nice if you handle the xo correctly).
There is a correction circuit for the woofer that I ordered. A cut up high and down low to correct recessed mids. I'll try both with and without it - boosted highs + lows might help an open back line array. If I make a 4 driver parallel/series assembly that'll come out the same impedence as 1 driver, so a single example of the circuit will work correctly for the 4 drivers, yes?
The drivers were cheap enough that I picked em up on a lark, but if anyone has tips or tricks on making it work I'd be glad to hear.
There is a correction circuit for the woofer that I ordered. A cut up high and down low to correct recessed mids. I'll try both with and without it - boosted highs + lows might help an open back line array. If I make a 4 driver parallel/series assembly that'll come out the same impedence as 1 driver, so a single example of the circuit will work correctly for the 4 drivers, yes?
The drivers were cheap enough that I picked em up on a lark, but if anyone has tips or tricks on making it work I'd be glad to hear.
Good for you, Adam. Go for it!
I have no problems with bass in this array. The CV drivers are only 5 bucks each from Apexjr.c0m and they have a fairly low Fs around 55hz or so.
Being that they're 16 ohm, I'm running all 8 of them in parallel. This equates to a 2 ohm load. My DIY power-buffer amplifier can handle a 1 ohm load so I'm set.
First thing I noticed when driving all eight in parallel (vs. series/parallel for 8 ohms) is that the bass is stronger, much stronger. I don't know why...
I do know that I'm simply falling in love with this set-up!
I have no problems with bass in this array. The CV drivers are only 5 bucks each from Apexjr.c0m and they have a fairly low Fs around 55hz or so.
Being that they're 16 ohm, I'm running all 8 of them in parallel. This equates to a 2 ohm load. My DIY power-buffer amplifier can handle a 1 ohm load so I'm set.
First thing I noticed when driving all eight in parallel (vs. series/parallel for 8 ohms) is that the bass is stronger, much stronger. I don't know why...
I do know that I'm simply falling in love with this set-up!
Carpenter, thanks for sharing your project with the forum.
This has been a fun lurk-along project.
I too found the drivers that Adam Thorne mentioned, though I was thinking about a different implementation. My plan is to use 16 drivers per side, with the outer 8 lowpassed, and the inner run fullrange ( and Eq'd for the midrange dip ) with a bullet horn centered, XO'd first order at 2K to avoid the comb lining that Dr. Griffin, Et Al mention in the papers on line arrays. with a line that tall ( almost 8' ) I should be able to keep my entire listening area in the near field. the baffle would be U style, and I'll need ~40" front to back ( driver center to center? ) to avoid dipole cancellation down to about 100Hz. A 24" baffle with 8" sides will get you there ( and the sides can be utilized to stabilize it too ).
Now I just need to petition the treasury for the funds.......
The're for the garage, they won't cost too much, you'll never have to see 'em, It'll keep me off the streets, yea that's the ticket.
John
PS: if you'd like to read Dr. Griffin's pdf go here:www.audioroundtable.com/misc/nflawp.pdf
This has been a fun lurk-along project.
I too found the drivers that Adam Thorne mentioned, though I was thinking about a different implementation. My plan is to use 16 drivers per side, with the outer 8 lowpassed, and the inner run fullrange ( and Eq'd for the midrange dip ) with a bullet horn centered, XO'd first order at 2K to avoid the comb lining that Dr. Griffin, Et Al mention in the papers on line arrays. with a line that tall ( almost 8' ) I should be able to keep my entire listening area in the near field. the baffle would be U style, and I'll need ~40" front to back ( driver center to center? ) to avoid dipole cancellation down to about 100Hz. A 24" baffle with 8" sides will get you there ( and the sides can be utilized to stabilize it too ).
Now I just need to petition the treasury for the funds.......
The're for the garage, they won't cost too much, you'll never have to see 'em, It'll keep me off the streets, yea that's the ticket.
John
PS: if you'd like to read Dr. Griffin's pdf go here:www.audioroundtable.com/misc/nflawp.pdf
thanks for the tipoff, just picked me up some of those peerless drivers. It mentions a filter for them, and it's mentioned here. I couldn't find out much about it though.
AdamThorne said:
These will be in the man cave, IE my shop. not even in the same building as she....
I'm trying to put together an entire system on the cheap, bought Maro Penasa's My Ref ( same as was originally sold by Twisted Pair ) amp kits on group buy, Pass Diy B-1 board, and silicon, working on speaks, interconnects, just need to decide on sources, I'd like to find a PS 1 to use as a CD player, and have an old Onkyo tuner in storage, no plans to put any of my Vinyl anywhere near all that sawdust and fumes tho....
I want tunes while I'm making messes.
John
Tea Bag,
If you'll go to the PE page for the speaker, and click the related items tab, they are selling an input cup with the filter already installed for something less than a $, IIRC the values for the filter components are listed there too.
There is a thread on those drivers on PE's forum, somebody even measured them, I couldn't get the file to open on my puter tho. You might be able to find more info there.
John
If you'll go to the PE page for the speaker, and click the related items tab, they are selling an input cup with the filter already installed for something less than a $, IIRC the values for the filter components are listed there too.
There is a thread on those drivers on PE's forum, somebody even measured them, I couldn't get the file to open on my puter tho. You might be able to find more info there.
John
I'm glad that my little project is appreciated; it's also a lot of fun chatting with your guys. 🙂
Carpenter, I'm not trying to hijack your thread....but....this is the only active Line Array thread I know of, and there's lots of really smart speaker builders about.... and I have a line array related question, I hope someone who know's more than I can answer, or direct me to where I can discover my own answers.
Here goes:
The Line source/array has valid uses and advantages, also disadvantages. One of the advantages is that the driver line acts as a single vertical radiator, producing a "column" of sound. This only works at spacing differences of less than 1 wavelength. Example: according to all I've read by Griffin, Ureda, et al; a 5.25" Dia. circular driver will produce the "columnar " effect up to 2582Hz, with sever comb lining ( disadvantage ) above double that (5164 Hz.). Therefore your crossover frequency should be guided by this effect.
In all that I have read no one mentions using a source having more than one row of drivers. There are probably valid reasons for this, but my brain wants to say add a second line of drivers directly adjacent to the first but offset 1/2 spacing higher/lower. Since the single row acts like a tall point source, would adding a second offset row allow you to raise the tuning Hz. before comb lining set in? Can double row act like a point source?
My reasoning for asking is I'd like to use a broadband driver to comprise most of the line, and add a tweeter crossed in above the critical hearing levels, say 5K Hz. effectively yielding a " Fullrange Linesource " with a tweeter.
I really want to know why this wont work.
I've studied Dr. Griffins Nearfield Line array paper, also his Linus Array paper, I'm in the process of studying Mark Ureda's JBL white papers, and spent some time looking back at past line array threads here and at Audio Circle. I've also looked at some of the stuff on the Pro forums, but I'm really only interested in nearfield listening.
John
Here goes:
The Line source/array has valid uses and advantages, also disadvantages. One of the advantages is that the driver line acts as a single vertical radiator, producing a "column" of sound. This only works at spacing differences of less than 1 wavelength. Example: according to all I've read by Griffin, Ureda, et al; a 5.25" Dia. circular driver will produce the "columnar " effect up to 2582Hz, with sever comb lining ( disadvantage ) above double that (5164 Hz.). Therefore your crossover frequency should be guided by this effect.
In all that I have read no one mentions using a source having more than one row of drivers. There are probably valid reasons for this, but my brain wants to say add a second line of drivers directly adjacent to the first but offset 1/2 spacing higher/lower. Since the single row acts like a tall point source, would adding a second offset row allow you to raise the tuning Hz. before comb lining set in? Can double row act like a point source?
My reasoning for asking is I'd like to use a broadband driver to comprise most of the line, and add a tweeter crossed in above the critical hearing levels, say 5K Hz. effectively yielding a " Fullrange Linesource " with a tweeter.
I really want to know why this wont work.
I've studied Dr. Griffins Nearfield Line array paper, also his Linus Array paper, I'm in the process of studying Mark Ureda's JBL white papers, and spent some time looking back at past line array threads here and at Audio Circle. I've also looked at some of the stuff on the Pro forums, but I'm really only interested in nearfield listening.
John
Why don't you build it and let us know how it sounds?
Frankly, I've had that very same thought, but the system sounds so good as it is that I can't see any reason to mess with it--leave well-enough-alone... I'm concerned that atempting to operate too many drivers in tandem will muck up the signal.
Frankly, I've had that very same thought, but the system sounds so good as it is that I can't see any reason to mess with it--leave well-enough-alone... I'm concerned that atempting to operate too many drivers in tandem will muck up the signal.
My feeling is there may be some glaring, and obvious reason not to. ( I just don't know what it is.)
I can't find any literature where it even mentions what I proposed, but I can't help but think that this isn't a new idea.
The closest I've come to describing what I mentioned in the earlier post is the JBL VerTec system for PA sound reinforcement uses.
The vertically stacked array cabinets each individually contain 2, 15" woofers on the outside, with 4,8" midrange driving a compression horn centered, with a single Compression driver driving a vertical wave guide in the center of the mid horn mouth ( if I understand the literature correctly ). These are crossed at 200/1600 IIRC. Overall size is about 48"W X 20" H.
My own thinking is to use the 5.25" closeout drivers PE has on sale, in a vented alignment. What I am designing for is a specific location: my shop, which has a couple of strikes against it. Square room, just under 24' either direction. 2 roll up doors,and a column in the center.) While I would like to go OB, I just can't have them sitting out in the work area. So, I'm trying to design for a large soundstage, that can play relatively loud without a whole lot of power, but also want best SQ for my $.
As ever, all speaker design is a compromise. No way could I sneak an 8' tall line array into my living space, SWMBO would not be amused, no matter how pretty I make them.
Carpenter, as I recall, your using the 6" CV mid's from Apex, and IIRC those are 16 Ohm, and you are running them all parallel? I know you commented that you had an Amp that was stable down to an OHM. At what distance are you listening, and how large is your room? I have a kit GB amp to assemble for the shop that will drive a 4 Ohm load, but I understand it's a bit more comfortable with a nom. 8 Ohm load, so that is another design goal.
I'm also curious about your TH sub, I know that you described it somewhere in the forum, because I remember reading about it, but I can't seem to find it now.
John
I can't find any literature where it even mentions what I proposed, but I can't help but think that this isn't a new idea.
The closest I've come to describing what I mentioned in the earlier post is the JBL VerTec system for PA sound reinforcement uses.
The vertically stacked array cabinets each individually contain 2, 15" woofers on the outside, with 4,8" midrange driving a compression horn centered, with a single Compression driver driving a vertical wave guide in the center of the mid horn mouth ( if I understand the literature correctly ). These are crossed at 200/1600 IIRC. Overall size is about 48"W X 20" H.
My own thinking is to use the 5.25" closeout drivers PE has on sale, in a vented alignment. What I am designing for is a specific location: my shop, which has a couple of strikes against it. Square room, just under 24' either direction. 2 roll up doors,and a column in the center.) While I would like to go OB, I just can't have them sitting out in the work area. So, I'm trying to design for a large soundstage, that can play relatively loud without a whole lot of power, but also want best SQ for my $.
As ever, all speaker design is a compromise. No way could I sneak an 8' tall line array into my living space, SWMBO would not be amused, no matter how pretty I make them.
Carpenter, as I recall, your using the 6" CV mid's from Apex, and IIRC those are 16 Ohm, and you are running them all parallel? I know you commented that you had an Amp that was stable down to an OHM. At what distance are you listening, and how large is your room? I have a kit GB amp to assemble for the shop that will drive a 4 Ohm load, but I understand it's a bit more comfortable with a nom. 8 Ohm load, so that is another design goal.
I'm also curious about your TH sub, I know that you described it somewhere in the forum, because I remember reading about it, but I can't seem to find it now.
John
You can run an open baffle design in you work space; just run grill cloth around the back of the speakers as well as the front. That's what I plan to do.
After hearing the open, airy qualities of the OB, there's little chance of getting me to switch back to a box enclosure. There's something very, very special about this design--wish I'd tried it sooner.
I can run the entire stack in parallel (2 ohm load) and it works just fine. I do notice a slight decrease in the amps ability to handle subtle transients, so I'm going to switch back to an 8 ohm configuration. The bass is stronger, but I prefer to hear the upper register details.
The amp is a simple three-stage device consisting of three differential pairs--the first pair being jfets, the second mid-size mosfets, the third is the large power mosfets configured in a follower mode fed by a center-tapped choke. The amp can soften the insulation on my supply wires. Needless to say, I'm getting larger wires! 😀
I'm planning to put my Tapped Horn layout on my web site: inlowsound dot c0m. It's such an amazing beast. The best part is it's scalable; you can shrink the drawing dimensions down from an 18 inch driver to a 10 inch unit and still get very good results.
One of my favorite things to do is gently tap on the cone of the driver when it's in an enclosure. In a bass reflex enclosure, the 18 has the typical dull thud, neutral. In the horn, the tap sounds more like the kick on a bass drum. Day and night!
I posted drawings of my layout in the tapped horn thread. I received very little feedback and eventually chose to unsubscribe from the thread. It seems to be occupied by people who enjoy discussing theory and software. This is a good thing, but I'm not using software, so have little to contribute--other than the physical unit itself.
I'd highly recommend building one for yourself. It's extremely easy to do. Home Depot has 1-1/8 inch plywood floor decking that won't break the bank. Makes for one very remarkable toy. Bass will never be the same! 😉
After hearing the open, airy qualities of the OB, there's little chance of getting me to switch back to a box enclosure. There's something very, very special about this design--wish I'd tried it sooner.
I can run the entire stack in parallel (2 ohm load) and it works just fine. I do notice a slight decrease in the amps ability to handle subtle transients, so I'm going to switch back to an 8 ohm configuration. The bass is stronger, but I prefer to hear the upper register details.
The amp is a simple three-stage device consisting of three differential pairs--the first pair being jfets, the second mid-size mosfets, the third is the large power mosfets configured in a follower mode fed by a center-tapped choke. The amp can soften the insulation on my supply wires. Needless to say, I'm getting larger wires! 😀
I'm planning to put my Tapped Horn layout on my web site: inlowsound dot c0m. It's such an amazing beast. The best part is it's scalable; you can shrink the drawing dimensions down from an 18 inch driver to a 10 inch unit and still get very good results.
One of my favorite things to do is gently tap on the cone of the driver when it's in an enclosure. In a bass reflex enclosure, the 18 has the typical dull thud, neutral. In the horn, the tap sounds more like the kick on a bass drum. Day and night!
I posted drawings of my layout in the tapped horn thread. I received very little feedback and eventually chose to unsubscribe from the thread. It seems to be occupied by people who enjoy discussing theory and software. This is a good thing, but I'm not using software, so have little to contribute--other than the physical unit itself.
I'd highly recommend building one for yourself. It's extremely easy to do. Home Depot has 1-1/8 inch plywood floor decking that won't break the bank. Makes for one very remarkable toy. Bass will never be the same! 😉
Isn't that what the selah audio "symmetrica" line array does ? Google for more info. I have a friend DIYing one of those at home and it should be complete in a week or two.mightym said:
My OB line arrays consisted of some cheapo $3 5.25" foster drivers which originally had a rising response. This counteracted , to an extent, the array roll-off . I still have a bit of a midrange BBC dip (my tweeters didn't like being crossed over below 5 KHz) but are still great fun to listen to (I use a horn sub below 80Hz, thoughthe arrays can work till 60hz). There's a sense of effortless ease when using high eff. speakers even at higher levels.
My advice is figure out where your woofers are likely going to roll off and then decide if a single or line of tweeters will work. One thing I can say is that full size line arrays are probably not the best thing if you're going to be too close to the speakers (the sound seems to lose focus). When my 6ft tall arrays are set up, I'm about 10 ft away and that's about the closest I can get to enjoy them.
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