Hello all,
I'm new here, but decided to go ahead and join because the internet brings me here to answer most of my questions about audio in general. Thanks to everyone for allowing my fist post to possibly be a stupid question.
My current system includes:
Antique sound lab wave line pre
2 DBX 234 active crossovers
Kenwood (sorry, don't know what model) 6 channel main amp
Maggie MG 3as
Crown XLS 402
2 JL Audio 12" w3 subs in sealed enclosure, compound push-pull arrangement.
If you can't tell, the system is 4-way and sounds pretty decent overall. It is an amalgomation of cheap parts and components that local Hi-Fi dealer reccomended, since I'm on a fairly tight budget.
On a side note, I have to say that tri-amping an old set of maggies will really bring them to life. My set had been passed around a few times before I got my hands on them, but I doubt any of those other owners EVER heard them sing like they do now! I conidered several options for subs and settled on the JL's out of convienience. The sound of these subs in a compound push-pull arrangement is nothing less than stunning.
I now find myself considering whether or not to let go of the aging maggies (they need too much work to keep them alive) and start over fresh. I had the pleasure of auditioning a set of line arrays that an acquaintance built, and was blown over backwards by their sound. His house sounded like a dance hall. What shocked me even more was that he said he used some of the cheapest drivers he could find, I believe MCM is the manufacturer. I never would have imagined that a handfull of cheapo drivers could sound like that! He used 12 4" drivers and 12 of these tiny tweeters that looked like car audio stuff. I'm wondering if coaxial drivers might be appropriate for a line array design. Any help you guys could provide would be greatly appreciated. I've considered some Hi-Vi Research car coaxial drivers for my new project. I know i'll give up control over the tweeters if I do this, but do you guys think it'd really matter? I welcome all opinions, criticisms and advice you guys could give.
Thanks in advance!
I'm new here, but decided to go ahead and join because the internet brings me here to answer most of my questions about audio in general. Thanks to everyone for allowing my fist post to possibly be a stupid question.
My current system includes:
Antique sound lab wave line pre
2 DBX 234 active crossovers
Kenwood (sorry, don't know what model) 6 channel main amp
Maggie MG 3as
Crown XLS 402
2 JL Audio 12" w3 subs in sealed enclosure, compound push-pull arrangement.
If you can't tell, the system is 4-way and sounds pretty decent overall. It is an amalgomation of cheap parts and components that local Hi-Fi dealer reccomended, since I'm on a fairly tight budget.
On a side note, I have to say that tri-amping an old set of maggies will really bring them to life. My set had been passed around a few times before I got my hands on them, but I doubt any of those other owners EVER heard them sing like they do now! I conidered several options for subs and settled on the JL's out of convienience. The sound of these subs in a compound push-pull arrangement is nothing less than stunning.
I now find myself considering whether or not to let go of the aging maggies (they need too much work to keep them alive) and start over fresh. I had the pleasure of auditioning a set of line arrays that an acquaintance built, and was blown over backwards by their sound. His house sounded like a dance hall. What shocked me even more was that he said he used some of the cheapest drivers he could find, I believe MCM is the manufacturer. I never would have imagined that a handfull of cheapo drivers could sound like that! He used 12 4" drivers and 12 of these tiny tweeters that looked like car audio stuff. I'm wondering if coaxial drivers might be appropriate for a line array design. Any help you guys could provide would be greatly appreciated. I've considered some Hi-Vi Research car coaxial drivers for my new project. I know i'll give up control over the tweeters if I do this, but do you guys think it'd really matter? I welcome all opinions, criticisms and advice you guys could give.
Thanks in advance!
Hi,
By using coax speakers you will have a separation of the tweeters. This is not good because you end up with comb filtering issues.
Quote from the PE site:
"Comb Filtering: An artifact seen in multi-driver systems that is the result of constructive and destructive interference from multiple point sources. The addition or subtraction of multiple sources will vary with location relative to the speaker. Comb filtering becomes more of a concern at higher frequencies due to the shorter wavelengths involved. Most often used when talking about line arrays where spacing between tweeters can be problematic."
By using coax speakers you will have a separation of the tweeters. This is not good because you end up with comb filtering issues.
Quote from the PE site:
"Comb Filtering: An artifact seen in multi-driver systems that is the result of constructive and destructive interference from multiple point sources. The addition or subtraction of multiple sources will vary with location relative to the speaker. Comb filtering becomes more of a concern at higher frequencies due to the shorter wavelengths involved. Most often used when talking about line arrays where spacing between tweeters can be problematic."
Thak you. This is exatly why I joined this morning. I've yet to see a coax/line array system in my quest. I guess that should've clued me in, yet at the same time I wonder how different designs for things mght work, never knowing who has tried what and been succesful. It's good to know that there is a place for my questons, as well as answers I can take to the bank and I thank you all.
My first thought was to possibly go with a line of Silver Flute tweeters and a line of discontinued Focal 5.25's from Zalytron. I've seen designs that use just one ribbon tweeter and have also considered donating the ribbons from my maggies to the cause, but am usure if this would even be a possibility. I'm definately open to suggestions here. I want to stay reletively cheap, but not as cheap as what I saw at my friends place. I can only magine that the results would be better if I use components that are a hair better than his.
My first thought was to possibly go with a line of Silver Flute tweeters and a line of discontinued Focal 5.25's from Zalytron. I've seen designs that use just one ribbon tweeter and have also considered donating the ribbons from my maggies to the cause, but am usure if this would even be a possibility. I'm definately open to suggestions here. I want to stay reletively cheap, but not as cheap as what I saw at my friends place. I can only magine that the results would be better if I use components that are a hair better than his.
If I had more time I would look for the white paper by Dr Jim Griifin. In the meantime why don't you mosey over here and see if you can dig up some ideas. Dr Griffin is a member here so have a look see at his posts. If you can't find something there then post again or google his white paper on line arrays.
http://www.diyaudio.com/forums/sear...63787053&sortby=lastpost&sortorder=descending
http://www.diyaudio.com/forums/sear...63787053&sortby=lastpost&sortorder=descending
An alternative would be a focused array, which will circumvent the combing issues. They have their own issues -smaller sweet spot than a line array etc., but they do allow things a line array doesn't.
Cal Weldon said:
see: http://www.linkwitzlab.com/Acoustics and Psychoacoustics of Loudspeakers in Small Rooms.doc
human hearing is insensitive to narrow notches, an established fact in psychoacoustics
I don't know, any comments?
Floyd Toole seems to be quite authoritative source
who am I to argue?
best,
graaf
True enough as far as it goes (at least assuming you're on-axis). What it doesn't cover is the severe attenuation of the high frequencies that is also a consequence, which need massive Eq to bring them ~flat once again.
See the FR curves of this project, using 2in TB drivers to see what I mean. http://www.partsexpress.com/projectshowcase/Kuze3201/Kuze3201.html You'll get pretty rough HF out of them, even when Eq'd approximately flat.
See the FR curves of this project, using 2in TB drivers to see what I mean. http://www.partsexpress.com/projectshowcase/Kuze3201/Kuze3201.html You'll get pretty rough HF out of them, even when Eq'd approximately flat.
xlr8 said:
They should be extractable. The ribbons in maggies would make an ideal support tweeter for a line array. Being as long as it is, you would have no gaps to cause comb filtering.
dave
Has anyone ever built and tested a line array using point source drivers like KEF makes?? this puts the tweeter at the center of the mid bass driver giving them natural time alignment, you might say they are the closest thing to a single full range driver which always sounded like a great idea to me..
my two pence..😀
my two pence..😀
onform said:
How high any driver can go in a line array is determined by its centre-to-centre spacing. In any coax the tweeter spacing will be the same as the midbass, so the tweeter can go no higher than the midbass (basically making it useless)
dave
onform said:
I don't think coaxially mounting a tweeter with a woofer gets them time-aligned. I think you'd have to adjust the other dimension -- forward / backward.
I think the idea is to get the "acoustic centers" of the drivers stacked up on top of each other. At least the Vandersteens seem to be doing this. Perhaps the further away you sit, and the higher the crossover frequency, the less it all matters. For supertweeters, I just mount them on the back of the cabinet anyway (worst conceivable alignment but airy and ear-pleasing, to me at least).
rjbond3rd -
I believe you've mentioned this elsewhere and it's caught my attention.
Can you direct me to a link with photos of what you've done?
I continue to be interested in line arrays despite all the mentioned problems aligning them properly.
One thing thats always seemed 'just not right' to me is the many configurations I see with an individual tweeter for each FR driver. It simply seems overkill regards highs being concerned . Most decent FR's do 100-12000 fairly well. Those of us plus 35 years of age don't hear real well above that region anyhow and I find many tweeters actually hurt my ears.
I like your idea as highs are 'faster' (can't think of better words to describe whats technically on my mind) so with backwave effect I'd think your idea would ultimately lead to better time alignment and more natural sounding highs.
Ribbons get expensive so my thoughts also go to 1 tweeter per 2 drivers mounted on front baffle. Even with OSB these 'experiments' get expensive.
Thanks - Bluto
I believe you've mentioned this elsewhere and it's caught my attention.
Can you direct me to a link with photos of what you've done?
I continue to be interested in line arrays despite all the mentioned problems aligning them properly.
One thing thats always seemed 'just not right' to me is the many configurations I see with an individual tweeter for each FR driver. It simply seems overkill regards highs being concerned . Most decent FR's do 100-12000 fairly well. Those of us plus 35 years of age don't hear real well above that region anyhow and I find many tweeters actually hurt my ears.
I like your idea as highs are 'faster' (can't think of better words to describe whats technically on my mind) so with backwave effect I'd think your idea would ultimately lead to better time alignment and more natural sounding highs.
Ribbons get expensive so my thoughts also go to 1 tweeter per 2 drivers mounted on front baffle. Even with OSB these 'experiments' get expensive.
Thanks - Bluto
Scottmoose said:
I agree
I know The Kuze project
My point is that comb filtering is not a problem AS SUCH, audible AS SUCH
attenuation of high frequencies IS the consequence and the problem
that is why all such designs need equalization passive as in case of Ted Jordan's linear array or active as in case of IDS25 by Roger Russell for example
best,
graaf
Bluto said:
Hi Bluto - I'm really just a newb at this point but I think you might be thinking of this discussion (which perhaps I was merely echoing):
http://www.diyaudio.com/forums/showthread.php?s=&postid=1490911
You've gotten some awesome suggestions above (Cal Weldon --> Dr. Jim Griffin, Scottmoose --> "focused array" and planet10 --> driver center-to-center spacing). Those guys are the real experts and they can help you refine any design you tackle.
In terms of staggering the drivers front to back, the attached photo gives an idea of what I was referring to. The Vandersteen site explains the design:
"Minimum-area baffles eliminate virtually all cabinet edge and grille diffraction anomalies while mass alignment of driver elements insures proper time arrival. "
http://www.vandersteen.com/pages/3alit.html
Good luck in your quest -- I hope you'll report back as it progresses!
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rjbond3rd said:
well, "THE real experts"?
Is not Dr. Floyd Toole a real expert?
Or EJ Jordan?
Or Siegfried Linkwitz?
Or Roger Russell of McIntosh?
Or Yoav Gonczarowski of YG Acoustics: http://db.audioasylum.com/cgi/m.mpl?forum=speakers&n=73211
comb filtering, driver spacing, blah blah
best,
graaf
Comb-filtering, driver spacing, blah-blah?!?
You said it yourself a post earlier: comb-filtering causes massive attenuation of the HF response. It's not separate from it. Ergo, 'blah-blah' is hardly the word that springs to mind, when you need major Eq (which not everyone either has the facility or inclination to use) to boost the HF into line with the rest of the FR.
The audibility of the related issue of very narrow notches in the rest of the FR when centre-to-centre spacing between operating drive-units exceeds 1 wavelength is a matter of greater question, I agree.
After Eq-ing out the other problems, then on-axis, you might get away with it with small drivers (almost no chance with anything over ~4 - 4.5in though). It likely will depend on the listener -some people tend to be more suseptable to such things than others.
Off axis is a different matter though & you're quite likely to end up with problems, & a very phasey response, which is a bit of a pain when one of the major reasons for / advantage of a straight line-array is the enlarged sweet-spot / area.
That's if I wanted a line of FR units, I'd personally be using a focused, rather than a straight, array. Sure, there are compromises (specifically a sweet-spot size similar to a single drive), but they are IMO less than the compromises of the alternative -requirement of Eq; possible audible roughness on-axis (design dependant) and non-too-great performance off-axis. YMMV.
You said it yourself a post earlier: comb-filtering causes massive attenuation of the HF response. It's not separate from it. Ergo, 'blah-blah' is hardly the word that springs to mind, when you need major Eq (which not everyone either has the facility or inclination to use) to boost the HF into line with the rest of the FR.
The audibility of the related issue of very narrow notches in the rest of the FR when centre-to-centre spacing between operating drive-units exceeds 1 wavelength is a matter of greater question, I agree.
After Eq-ing out the other problems, then on-axis, you might get away with it with small drivers (almost no chance with anything over ~4 - 4.5in though). It likely will depend on the listener -some people tend to be more suseptable to such things than others.
Off axis is a different matter though & you're quite likely to end up with problems, & a very phasey response, which is a bit of a pain when one of the major reasons for / advantage of a straight line-array is the enlarged sweet-spot / area.
That's if I wanted a line of FR units, I'd personally be using a focused, rather than a straight, array. Sure, there are compromises (specifically a sweet-spot size similar to a single drive), but they are IMO less than the compromises of the alternative -requirement of Eq; possible audible roughness on-axis (design dependant) and non-too-great performance off-axis. YMMV.
graaf said:
Graaf, I apologize I omitted you from my silly list of "real experts." The omission was not intentional, as I only wanted to make the point that Bluto should not mistake me for an expert!
My knowledge would not fill a thimble. I only meant to steer Bluto to the other posters on this thread, you included!
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I have a really nice line array with 20 tang band full range drivers per side. If comb filtering is a big issue I sure can not hear it. If you ever have a chance to listen to a nice array with good source material and quality hardware you might find out just how nice they sound.
All of the technical babble concerning hi-fi can really get in the way. Sometimes you just have to build something and hear it first hand. I was curious when Roger Russell after 40 years building speakers for Mcintosh decided to pen his reputation to a line array speaker. Go figure. That man should know what he is doing.
Go ahead and build an inexpensive array and try it. You might be pleasantly surprised. You can find bulk deals at Parts Express every now and then on small drivers and MDF board is not too expensive. Tad
You can also offset the speakers side to side as you progress up if you want to help cancel some of this combing effect.
All of the technical babble concerning hi-fi can really get in the way. Sometimes you just have to build something and hear it first hand. I was curious when Roger Russell after 40 years building speakers for Mcintosh decided to pen his reputation to a line array speaker. Go figure. That man should know what he is doing.
Go ahead and build an inexpensive array and try it. You might be pleasantly surprised. You can find bulk deals at Parts Express every now and then on small drivers and MDF board is not too expensive. Tad
You can also offset the speakers side to side as you progress up if you want to help cancel some of this combing effect.
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