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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Mark Monson on December 13, 2011, 02:37:23 PM
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Thanks again to all of the knowledgeable people who unselfishly share their knowledge and experience. I am looking at buying subs for my classic rock band PA. "Back in the day" all of the high end subs were in folded horn or other type of enclosures "tuned" to amplify lower frequencies. Now it seems that half of the high end subs are in direct radiator cabinets. The direct radiator subs would certainly be easier to transport and store, but I would not want to sacrifice a significant amount of sound quality. What are the pros and cons of sub enclosures?
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Thanks again to all of the knowledgeable people who unselfishly share their knowledge and experience. I am looking at buying subs for my classic rock band PA. "Back in the day" all of the high end subs were in folded horn or other type of enclosures "tuned" to amplify lower frequencies. Now it seems that half of the high end subs are in direct radiator cabinets. The direct radiator subs would certainly be easier to transport and store, but I would not want to sacrifice a significant amount of sound quality. What are the pros and cons of sub enclosures?
You are right that (in most cases) a folded horn has a larger footprint than a typical direct radiating subwoofer. In cases where a folded horn is not larger (or is not much larger) than say a dual 18" DR sub, the folded horn is likely to be compromised and does not behave fully as a bass horn.
Back in the day (which you refer to) "we" often preferred folded horns because they provided more acoustic outut (within their passband) and (just as likely) the DR subwoofer drivers simply ran out of steam. Sometime during the late 1980's, cone drivers began to become available with greater power handling and slightly higher sensitivity. At the same time, power amps were developed with significantly greater output. So we began to introduce (or observe others who began to use) direct radiating subwoofer systems that could get as loud (or loud enough) as our folded horns had and they took up less truck, van and stage space *and* went lower. We began to experience and appreciate life below 50Hz ;D
One of the sonic characteristics which almost all folded horns exhibited was compression. Which makes sense when you consider that sound is being squeezed into a small throat and then allowed to expand as the flare travels (expands) through the enclosure and exits via the mouth. Horn Theory 101.
When we tranistioned to DR subs, I was in love with the extended LF response (this was also when 5-string basses became a significant trend, thus response went down to 32Hz) and smaller size plus the lower load impedance to the amplifiers. But I also missed the very nice, acoustic/mechanical compression which tightened up the kick drum and bass (slapped or plucked/walking).
Over time I guess I got used to DR subs and relied more on electronic compression to get what we wanted. Alot of people did this.
There are folded horns available now which, for all intents and purposes, go as low as DR subs ....... or low enough. Tom Danley's tapped horns come immediatley to my mind. But they still have to follow the rules (laws of physics) and are larger than most dual 18" DR enclosures will be. The LAB Sub is an iteration of Danley's design philosphy and seems to work in much the same way as their tapped horns do.
It would be intersting to calculate and compare the footprint of a DR subwoofer system versus (say) one with Danley tapped horns (or other folded horn systems) where each provide the same acoustic output and low frequency limit. And also compare cost.
I believe that DR sub systems are still used more widely at all levels of the industry (including installed systems) than folded horns. But perhaps not by a huge margin. And I, for one, strongly believe that the new breeds of well-designed bass horns have their place.
In your own search for an appropriate subwoofer it is likely that a DR will suit you best. There are a lot of very good devices out there. And there's a good amount of crap. In my experience, cost is a huge factor. There simply are no (comparative) "bargains" when it comes to moving lots of air while being reliable and sounding good.
Try before you buy.
Hopefully this somewhat helps to answer your query.
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Tom, that was a very well-thought response, one of the best I've seen here.
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Tom, that was a very well-thought response, one of the best I've seen here.
Totally agree. Thanks Tom for a retrospective that was very helpful in filling in some gaps for me.
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Totally agree. Thanks Tom for a retrospective that was very helpful in filling in some gaps for me.
Thanks, guys !
Glad to post on this subject and that it provided something useful.
I hope others chime in.
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There's a sub line out there from Yorkville that's actually a little bit of both designs: the rear loaded quasi-horn LS808/801p. They are a little boomy but that's a positive in my book for classic rock. The most popular classic rock band in my area uses four of these babies, and I can't think a better sub for those guys. They make kick hits sound like cannons going off.
Anyway, I'd definitely put them on your shopping list. A good sub for this intended purpose.
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Thanks again to all of the knowledgeable people who unselfishly share their knowledge and experience. I am looking at buying subs for my classic rock band PA. "Back in the day" all of the high end subs were in folded horn or other type of enclosures "tuned" to amplify lower frequencies. Now it seems that half of the high end subs are in direct radiator cabinets. The direct radiator subs would certainly be easier to transport and store, but I would not want to sacrifice a significant amount of sound quality. What are the pros and cons of sub enclosures?
I have a pair of Cerwin Vega LR36 folded horns which I power with a Crown K2 amp. When I purchased these (over 10 years ago now), there wasn't anything out there that could put out the volume of bass that was anywhere near their price or size (I did like the JBL SR double 18's better, but you really had to have a road crew to move those things).
I am currently using a pair of CVA118 subs and a pair of DSR112's over the top.
The CVA's are not anywhere near what is possible out there today; however, they do fine for crowds of <200 indoors. I only use the folded horns for outdoor gigs or larger venues ..... and that isn't very often.
A pair of more modern powered DR speakers like the JBL PRX618 XLF's would be pretty ideal for most bar crowds. The LS801P mentioned above absolutely thunders.
I have actually grown to like the sound of DR better. It seems ..... tighter to my ear. The folded horns seem a bit (this is going to sound funny) woofey ;)
I sure don't miss moving the folded horns and that amp rack :)
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Tom
You are an example of what makes this forum great. That was a thorough, well thought out answer that really helps. As an old guy I can show some of the young bucks that what I used to do still has some value.
Mark
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No expert here but don't folded horn subs push the bulk of the air in one direction so if you standing by side of the sub 20ft away vs being in front of the it 20ft there's huge volume difference?
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No expert here but don't folded horn subs push the bulk of the air in one direction so if you standing by side of the sub 20ft away vs being in front of the it 20ft there's huge volume difference?
It depends on the freq in question, the size of the cabinet etc.
And how much is a "huge" difference? 6dB 10dB 20dB?
There can be some directivity-depending on various factors.
Remember that large waveforms are harder to "control" than smaller waveforms.
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It depends on the freq in question, the size of the cabinet etc.
And how much is a "huge" difference? 6dB 10dB 20dB?
There can be some directivity-depending on various factors.
Remember that large waveforms are harder to "control" than smaller waveforms.
I would add that at 80Hz (the most common ballpark crossover frequency for subs) and below the wavelengths are 14' and longer. It is hard to imagine a typical folded horn being capable of containing these long wavelengths.
I've mixed more than my share of monitors while behind the FOH stacks and I don't recall the folded horn systems being any less loud than the DR's back there :(
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Don B. Keele has a paper comparing low-frequency horns to direct radiators based on volumetric efficiency, wherein he finds that for a given amount of cubic volume, direct radiating speaker systems produce more output than comparable horn-loaded systems. Per-driver, horns are the most efficient. However, per cubic foot of tractor-trailer space, vented systems are the way to fit the most bass into the least space (hey, that rhymes -- I should be in marketing). This research effort took place during the development of the first JBL VerTec line array systems.
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20%281976-05%20AES%20Preprint%29%20-%20Efficiency,%20Horns%20vs%20DR.pdf (http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20%281976-05%20AES%20Preprint%29%20-%20Efficiency,%20Horns%20vs%20DR.pdf)
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Don B. Keele has a paper comparing low-frequency horns to direct radiators based on volumetric efficiency, wherein he finds that for a given amount of cubic volume, direct radiating speaker systems produce more output than comparable horn-loaded systems. Per-driver, horns are the most efficient. However, per cubic foot of tractor-trailer space, vented systems are the way to fit the most bass into the least space (hey, that rhymes -- I should be in marketing). This research effort took place during the development of the first JBL VerTec line array systems.
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20%281976-05%20AES%20Preprint%29%20-%20Efficiency,%20Horns%20vs%20DR.pdf (http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20%281976-05%20AES%20Preprint%29%20-%20Efficiency,%20Horns%20vs%20DR.pdf)
The caveat is that you also trade up in terms of power input requirements. For larger shows with big generators that's not a huge issue. For some of the smaller non-profit stuff I've done where I'm handed a 3000W genny or a 15 amp circuit, that can make the difference between constant breaker trips or an uninterrupted show.
In regards to horns sounding "woofy", driver quality and EQ can make a big difference. The pressure in a horn puts far more strain on the driver so you need something that can hold up and do it accurately. I use the larger BFM Titan48's and their natural rising sensitivity means you need to EQ the top end above 80Hz down to flatten their response otherwise they sound boomy due to the over-emphasis in that range. OTOH, folded horn paths filter out much of the harmonic distortion that DR subs produce and tend to produce cleaner output as a result. Some like it, others don't.
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My experience with horn subs, has never been great, the move to direct radiating subs has (IMHO) been a blessing for live sound. I was never a lover of bandpass boxes either, again far too coloured and a real tendency towards one or two note bass.
I am still waiting to see someone instigate a really good example of truncated transmission line. In my experience I have found good TL designs to offer really great extension and an ability to "fill the room" even with limited numbers/size of speakers, albeit at low SPL's (bearing in mind to my knowledge no examples exist in the professional sound reinforcement market. In the past most TL design has been of the "rule of thumb" type with extensive testing and tweaking to achieve desired results, however, George Augspurger and Martin King have in very recent years both produced reliable, mathmatical models, Auspurger via an electrical model and King via a mechanical model, interestingly both's work arrive at similar results and conclusions. From what I remember I believe that Martin discarded the long held belief that stuffing slowed the speed of the air within the line, he further tested this to prove it was indeed the case and built his model from there. My understnading means that transmission lines can very succesfully be produced with much shorter lines than previously thought. Bing that most subs now are crossed over at around 80hz (possibly a little higher) the damping of the ripples should prove less of an issue.
I'd be very interested in your thoughts Tom.
My appologies for drifting way off topic, however, with Tom posting on the thread I couldn't resist!
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It depends on the freq in question, the size of the cabinet etc.
And how much is a "huge" difference? 6dB 10dB 20dB?
There can be some directivity-depending on various factors.
Remember that large waveforms are harder to "control" than smaller waveforms.
Okay just remember seeing a band with folded horn and every time I went to walk to the side of the subs you could hear a huge difference in volume loss on the kick and bass but once you got back in front they would hit you hard. Keep in mind this was many moons ago like back in the 90's I can't even remember hat subs they had just remember they were folded horn design and huge and look like you needed a forklift to move them around.
All thought the band was kick ass hair metal type.
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My experience with horn subs, has never been great, the move to direct radiating subs has (IMHO) been a blessing for live sound. I was never a lover of bandpass boxes either, again far too coloured and a real tendency towards one or two note bass.
What models of bass horns do you have experience with? There are a number of more modern designs that IMO do quite well. I wholeheartedly agree that band pass subs have no place in the world of audio.
I've noticed some directionality with my Titans as well, especially outdoors without boundary reflections. I'd guess the longer horn path controls more of the upper end of their range which can impact some of the punch feel. It may also have something to do with placement and alignment of the subs.
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What models of bass horns do you have experience with? There are a number of more modern designs that IMO do quite well. I wholeheartedly agree that band pass subs have no place in the world of audio.
I've noticed some directionality with my Titans as well, especially outdoors without boundary reflections. I'd guess the longer horn path controls more of the upper end of their range which can impact some of the punch feel. It may also have something to do with placement and alignment of the subs.
Many over the years, initially the first I encountered were the Martin "w" bins, IMHO truly awful "boink" boxes, no bottom end at all. Others that spring to mind are Turbosound, Court Acoustic W bins (they had the advantage of porting to the front that gave the impression of more bass, Martin Wavefront folded horn boxes, none of these ever did it for me, have been using direct radiating boxes for last 15-18 years so I am probably not qualified to talk about anyone's latest developments in "horn" loaded boxes, that being said, I can't see how anyone has overcome the physics to give you a "true" bass response, outside of electronic jiggery.
Just as an afterthought, I am talking about horn's with no direct radiation, not semi hybrid designs.
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Here ago about these sub which is neither FH or DR, but coaxial
http://www.youtube.com/watch?v=Q5S_DIEDMOs
I know their for stage wedges but thought they looked cool and all the different ways you can stack them. I'm with the OP on the quasi Yorkville design pretty cool design.
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Thanks again to all of the knowledgeable people who unselfishly share their knowledge and experience. I am looking at buying subs for my classic rock band PA. "Back in the day" all of the high end subs were in folded horn or other type of enclosures "tuned" to amplify lower frequencies. Now it seems that half of the high end subs are in direct radiator cabinets. The direct radiator subs would certainly be easier to transport and store, but I would not want to sacrifice a significant amount of sound quality. What are the pros and cons of sub enclosures?
Back in the day Crown, Phase Linear etc had max of 200 to 300 per channel
into 8 ohms.. Thus efficiency was the "horn loaded subs and cabs
As Tom stated you can go with Lab Grupens and Itechs and have 1500 per channel or more into 8 ohms real easy and the loudspeakers can take a lot more power as well and are more efficient in the 1w per 1m spec.
Space is an issue as well...I do remember the Floyd tour having something like 24 semi loads of gear back in the Animals tour in 77.
Horns are big...horns are well..just plain Fu#king cool but not optimal in this day and age. I have a bunch of old horn loaded cabs and I just cant get myself to burn them.
They sit and take up space in my storage. One day I will burn them...I just know it
:)
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Back in the day Crown, Phase Linear etc had max of 200 to 300 per channel
into 8 ohms.. Thus efficiency was the "horn loaded subs and cabs
As Tom stated you can go with Lab Grupens and Itechs and have 1500 per channel or more into 8 ohms real easy and the loudspeakers can take a lot more power as well and are more efficient in the 1w per 1m spec.
Space is an issue as well...I do remember the Floyd tour having something like 24 semi loads of gear back in the Animals tour in 77.
Horns are big...horns are well..just plain Fu#king cool but not optimal in this day and age. I have a bunch of old horn loaded cabs and I just cant get myself to burn them.
They sit and take up space in my storage. One day I will burn them...I just know it
:)
Seen the Animals tour in 78 great concert.
Back then before the arrays the SE's didn't mix a giant roar mix like today's rock concerts.
AC/DC nice pretty roar :P
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Okay just remember seeing a band with folded horn and every time I went to walk to the side of the subs you could hear a huge difference in volume loss on the kick and bass but once you got back in front they would hit you hard. Keep in mind this was many moons ago like back in the 90's I can't even remember hat subs they had just remember they were folded horn design and huge and look like you needed a forklift to move them around.
All thought the band was kick ass hair metal type.
My experience lies completely with commercially made (or copied) bass horns. None of these was big enough to need a forklift. A large enough folded bass horn could provide some off axis attenuation.
Another possible contributor is that if you walked to the outside of split L&R bass horns there would be less combined LF energy, IOW you are walking out of "power alley".
HTH
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My experience with horn subs, has never been great, the move to direct radiating subs has (IMHO) been a blessing for live sound. I was never a lover of bandpass boxes either, again far too coloured and a real tendency towards one or two note bass.
I am still waiting to see someone instigate a really good example of truncated transmission line. In my experience I have found good TL designs to offer really great extension and an ability to "fill the room" even with limited numbers/size of speakers, albeit at low SPL's (bearing in mind to my knowledge no examples exist in the professional sound reinforcement market. In the past most TL design has been of the "rule of thumb" type with extensive testing and tweaking to achieve desired results, however, George Augspurger and Martin King have in very recent years both produced reliable, mathmatical models, Auspurger via an electrical model and King via a mechanical model, interestingly both's work arrive at similar results and conclusions. From what I remember I believe that Martin discarded the long held belief that stuffing slowed the speed of the air within the line, he further tested this to prove it was indeed the case and built his model from there. My understnading means that transmission lines can very succesfully be produced with much shorter lines than previously thought. Bing that most subs now are crossed over at around 80hz (possibly a little higher) the damping of the ripples should prove less of an issue.
I'd be very interested in your thoughts Tom.
My appologies for drifting way off topic, however, with Tom posting on the thread I couldn't resist!
I actually have no opinion. Transmission lines are something I have read about but have zero experience with.
I am also not much of a fan of bandpass boxes. Most I have heard are "1-note-wonders". A few have been sort of impressive. But not that much.
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I've never built one myself, (I've toyed with the idea a couple of times, just for fun, but time has been the factor), But I do have a PMC sub on a home cinema system. 10" volt driver, cabinet about 3 x 2 x 1 ft, room 30 x 20 ft with a 19ft vaulted ceiling, watching a film like "Sum of all Fears" where when they set the nuclear explosion off the SFX boys decided to have a synth sweep down through the floor. It's smooth in volume level and as it gets out of hearing range you feel it run through your body. My listening experience has always lead me to believe that they somehow coupled bass end with rooms better, it might be just lack of colouration due to port/cabinet artifacts.
I must get round to building a couple, just for fun, to go under a couple of band boxes for local 200-300 people shows, not that I do many of that type these days.
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Many over the years, initially the first I encountered were the Martin "w" bins, IMHO truly awful "boink" boxes, no bottom end at all. Others that spring to mind are Turbosound, Court Acoustic W bins (they had the advantage of porting to the front that gave the impression of more bass, Martin Wavefront folded horn boxes, none of these ever did it for me, have been using direct radiating boxes for last 15-18 years so I am probably not qualified to talk about anyone's latest developments in "horn" loaded boxes, that being said, I can't see how anyone has overcome the physics to give you a "true" bass response, outside of electronic jiggery.
Just as an afterthought, I am talking about horn's with no direct radiation, not semi hybrid designs.
Same here. W bins tend to be pretty short horn paths and not what I'd consider a true bass horn. My Titan 48 is admittedly a big box, but it's about a 14ft path length and effective down to 35 Hz. Its larger sibling the Tuba 60 is bigger still with control down into the mid 20's. Takes a big box to render a long path length and a large enough horn mouth to be effective and even then they're always most effective in herds. Danley's TH115 is supposedly good down to 40Hz flat and will put out some serious bass with its high efficiency. I'm willing myself to sacrifice the pack space for the clean output and efficiency. When it comes down to it, mine isn't much larger than a 2x18, it sounds cleaner IMO than any of the 2x18's I've mixed on, it hangs with the average 2x18" in output, I can power 4 off a PLX3602 or larger, and they weigh about 100lbs each.
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How big is too big for mobile use? Just curious.
I build front-loaded horns (have been for 35 years), and it has always been my experience that the speaker excursion is significantly less than that in vented boxes. Can't vouch for folded horns, as I haven't played with one in years.
Ivan and others are correct, horns can be directional or not, depending upon the specific design and size. I can say that a large (96" d x 96 h x 48 w) horn is very directional.
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How big is too big for mobile use? Just curious.
I build front-loaded horns (have been for 35 years), and it has always been my experience that the speaker excursion is significantly less than that in vented boxes. Can't vouch for folded horns, as I haven't played with one in years.
Ivan and others are correct, horns can be directional or not, depending upon the specific design and size. I can say that a large (96" d x 96 h x 48 w) horn is very directional.
Varies by available pack space and application, IMO. If it's a little wedding with light background music I'm loading rig into a sedan for, any sub is probably too big. ;)
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My experience lies completely with commercially made (or copied) bass horns. None of these was big enough to need a forklift. A large enough folded bass horn could provide some off axis attenuation.
Another possible contributor is that if you walked to the outside of split L&R bass horns there would be less combined LF energy, IOW you are walking out of "power alley".
HTH
Could have been I walked out of the power alley.
What do they use in the array subs aren't those Direct or they a little of both ?
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What do they use in the array subs aren't those Direct or they a little of both ?
I am a bit confused by the question. Maybe you can restate it so it makes more sense?
If you are asking if different types of subs are used-as a general rule, it is not a good idea to mix different types (models and styles-even from the same manufacturer) of subs.
This is because of the different phase response of the different models. At some freq they will add togethers nicely and at other freq they will cancel either a little or a lot.
In the "perfect" world the most summation you can get is 6dB when you double the number of subs.
HOWEVER, in the "perfect" world, you can get infinate or total cancellation at some freq if the phase is 180° out (at the point of measurement. Other positions would be different.
All sorts of arrays can be built to direct energy in a specific direction-or to cancel in a certain direction-or change the width of the pattern etc.
It just depends on the end result needed-the tools and space available and the skill/knowledge of the person designing the array.
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I am a bit confused by the question. Maybe you can restate it so it makes more sense?
If you are asking if different types of subs are used-as a general rule, it is not a good idea to mix different types (models and styles-even from the same manufacturer) of subs.
This is because of the different phase response of the different models. At some freq they will add togethers nicely and at other freq they will cancel either a little or a lot.
In the "perfect" world the most summation you can get is 6dB when you double the number of subs.
HOWEVER, in the "perfect" world, you can get infinate or total cancellation at some freq if the phase is 180° out (at the point of measurement. Other positions would be different.
All sorts of arrays can be built to direct energy in a specific direction-or to cancel in a certain direction-or change the width of the pattern etc.
It just depends on the end result needed-the tools and space available and the skill/knowledge of the person designing the array.
I was asking about array subs are they DR type of subs or FH type of subs or a little of both? I know about not mixing two different type subs together.
Just wondering about the array subs like at the AC/DC last tour had a array system, but it was just a loud roar I don't understand any thing they played kind of disappointment to. :(
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I was asking about array subs are they DR type of subs or FH type of subs or a little of both? I know about not mixing two different type subs together.
Just wondering about the array subs like at the AC/DC last tour had a array system, but it was just a loud roar I don't understand any thing they played kind of disappointment to. :(
Sub woofer arrays can be made up of either type. The choice depends on the desired result.
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I was asking about array subs are they DR type of subs or FH type of subs or a little of both? I know about not mixing two different type subs together.
Just wondering about the array subs like at the AC/DC last tour had a array system, but it was just a loud roar I don't understand any thing they played kind of disappointment to. :(
There is no such thing as "array subs"-as Tim pointed out. And array can be mode up of whatever type you want/have.
The closest thing to a "array sub" would be folded horns in which to get the best perfromance they need to be used in multiples to get the mouth are larger to extend the low freq response and get it smoother.
An "array" can take on many different form factors. Everything being simply stacked up in big pile to being lined up across the front of the stage-to directivity arrays etc.
It is the person who is in charge of "design" that whould know what the advantages AND disadvantages of each type of sub array are and choose whether nor not it is proper for the particualr job at hand.
In the AC/DC example you quote-I would not blame the type of sub, but rather the designer or the engineer or somebody else who may have had "control" over the sound. And was it that the bass was to loud (hwere you were at) or that the PA didn't have enough mids/highs to cover your seats- Maybe they were the "cheap seats" so to speak.
In some cases the FOH guy may not be as "in control" as they would like. Sometimes there is a "road manager" who is directing the FOH guy to get a particular "sound". Yes it may not good for the band, but those guys are out there. If you want to be paid- you do what they say and move on to the next gig.
It is really hard to judge a particular system by simply being a person in the audience. There are soooo many other variables that go into it, that you have no idea about-that you cannot say that one speaker is better than another or what the sound is really like-unless YOU are driving it and understand all that went into the design.
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First of all, Direct Radiator is not an apt description for a front loaded sub. It is not definitive.
It could be either a Bass Reflex, (ported enclosure design), or an Infinite Baffle design, (which is sealed enclosure), like Bagend uses. They are completely different.
They are most likely to be Bass Reflex designs in the PSR world.
Second of all, Bill Wood's LS1208 and LS808, along with it's Active versions are NOT Quasi Horns or Folded Horns. They are called "Bass Pipes" which was Bill's name for a "front loaded woofer with a very large port". Those quotes are his words.
The LS608 is a Quasi Horn and I saw it first used by Peavey on a 3way Double 15 box which was a horn, a woofer, and another of the same woofer crossed lower in the same cabinet configuration as you see in the LS608.
Todd Michael's USC1/USC1P are the only Folded Horns that Yorkville Sound makes.
I have the MEASURED frequency response charts for all of them.
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The LS1208 is NOT a front loaded speaker. It faces down from the top of the cabinet into a horn. There is no other speaker radiation EXCEPT for that horn.
Here is a direct quote from Bill Woods:
"This is a special condition of a conical horn, made for low frequencies. It does not relay on mouth area. This is a prototype, and will undergo testing shortly. Horns of this type require considerable R&D before getting it right. In another post, i showed curves of a 15" woofer in a conical bass horn- note how smooth, sensitivity, and low cutoff. generally, this type of horn yeilds the lowest cutoff in the smallest possible enclosure. the Yorkville SW1200 is an 18" folded conical horn."
The SW1200 is the precursor to the LS1208 and Bill seems to think it is a folded conical horn. Here is the link to the discussion. (Bill is known on the thread as "RCA-fan" so you can find his quotes where he says this.)
http://oswaldsmillaudio.com/forum2/index.php?topic=90.0
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The LS1208 is NOT a front loaded speaker. It faces down from the top of the cabinet into a horn. There is no other speaker radiation EXCEPT for that horn.
Here is a direct quote from Bill Woods:
"This is a special condition of a conical horn, made for low frequencies. It does not relay on mouth area. This is a prototype, and will undergo testing shortly. Horns of this type require considerable R&D before getting it right. In another post, i showed curves of a 15" woofer in a conical bass horn- note how smooth, sensitivity, and low cutoff. generally, this type of horn yeilds the lowest cutoff in the smallest possible enclosure. the Yorkville SW1200 is an 18" folded conical horn."
The SW1200 is the precursor to the LS1208 and Bill seems to think it is a folded conical horn. Here is the link to the discussion. (Bill is known on the thread as "RCA-fan" so you can find his quotes where he says this.)
http://oswaldsmillaudio.com/forum2/index.php?topic=90.0
Stuart, I stand corrected.....the LS808 and it's variants are front loaded.
You are correct, (of course), regarding the LS1208. It slipped my mind that they are indeed as you say. You owned them for years, so no wonder what I wrote stuck out in your mind.
This however is what is written on the Yorkville website on the LS1208 product page.
This information was confirmed by Todd Michaels who is their current designer.
A two year investigation into the optimization of high output low frequency sound has yielded the LS1208 “basspipe” subwoofer system. The "basspipe" is a multiple flare horn, connected to an organ like pipe, slowly flaring to the mouth. The bandwidth is narrowed, optimized to a specific range in the lower registers. Outdoor measurements show very smooth, very high output in the 35Hz to 200Hz range. This is the highest efficiency that we have ever seen for a single 18” driver enclosure, especially with a gross volume of only 22 cubic feet. In addition, a significant gain is achieved when using two units side by side as the mouth nears maximum acoustic load.
Stuart.......did you run them on their sides with the mouths coupled?
I run my LS608s in fours with the bottom two subs upsidedown and couple the mouths by running the top two upright.
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I have coupled them side by side, bottom to bottom, and blocked as a group of four before. Practicality (my QRX212 tops don't pole mount so I need the subs upright) dictates a side by side almost all the time.
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Don B. Keele has a paper comparing low-frequency horns to direct radiators based on volumetric efficiency, wherein he finds that for a given amount of cubic volume, direct radiating speaker systems produce more output than comparable horn-loaded systems. Per-driver, horns are the most efficient. However, per cubic foot of tractor-trailer space, vented systems are the way to fit the most bass into the least space (hey, that rhymes -- I should be in marketing). This research effort took place during the development of the first JBL VerTec line array systems.
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20%281976-05%20AES%20Preprint%29%20-%20Efficiency,%20Horns%20vs%20DR.pdf (http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20%281976-05%20AES%20Preprint%29%20-%20Efficiency,%20Horns%20vs%20DR.pdf)
An apt explanation ;)
For the same driver, a folded horn creates more SPL. IME, it feels like around 6db more (where 10db would be an experienced doubling and 3db a noticeable difference).
For the same size box, a DR puts out more SPL than a horn loaded sub.
As for directivity, I have never noticed it from folded horns; however, I am not sure I ever tried using them on a gig where I attempted to radiate to something like 180 degrees or more (and actually went and measured SPL).
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There is no such thing as "array subs"-as Tim pointed out. And array can be mode up of whatever type you want/have.
The closest thing to a "array sub" would be folded horns in which to get the best perfromance they need to be used in multiples to get the mouth are larger to extend the low freq response and get it smoother.
An "array" can take on many different form factors. Everything being simply stacked up in big pile to being lined up across the front of the stage-to directivity arrays etc.
It is the person who is in charge of "design" that whould know what the advantages AND disadvantages of each type of sub array are and choose whether nor not it is proper for the particualr job at hand.
In the AC/DC example you quote-I would not blame the type of sub, but rather the designer or the engineer or somebody else who may have had "control" over the sound. And was it that the bass was to loud (hwere you were at) or that the PA didn't have enough mids/highs to cover your seats- Maybe they were the "cheap seats" so to speak.
In some cases the FOH guy may not be as "in control" as they would like. Sometimes there is a "road manager" who is directing the FOH guy to get a particular "sound". Yes it may not good for the band, but those guys are out there. If you want to be paid- you do what they say and move on to the next gig.
It is really hard to judge a particular system by simply being a person in the audience. There are soooo many other variables that go into it, that you have no idea about-that you cannot say that one speaker is better than another or what the sound is really like-unless YOU are driving it and understand all that went into the design.
Oh I thought you can fly subs since I seen that the JBL VXR subs have flyware.
Keep in mind I don't know much about speaker design and what does what
Not sure middle of floor seats are considered cheap seats or not maybe should have went up to the cheap seat now that you mention cheap seats probably would have enjoyed it better. It's all good there Ivan and thinks for the info. learn a little every day here. 8)
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First of all, Direct Radiator is not an apt description for a front loaded sub. It is not definitive.
It could be either a Bass Reflex, (ported enclosure design), or an Infinite Baffle design, (which is sealed enclosure), like Bagend uses. They are completely different.
They are most likely to be Bass Reflex designs in the PSR world.
Are you aware that some folded horns are bass-reflex ?
HF drivers (compression drivers, ribbons and dome tweeters) may be horn-loaded or direct radiating. Before you assume this is an error: there have been some recording studio monitors designed with non horn-loaded 4" compression drivers (sort of super dome tweeters).
Bag End ELF systems are probably the only non-ported/infinite baffle subwoofer made/used for live sound and although they are fairly well known, they are not widely used.
Bass-refelx and/or infinite baffle are sub (no pun) sets of the direct-radiator class, or category, of low and low-mid frequency loudspeaker enclosures.
I think that "direct radiator" is the most appropriate term for those drivers with no horns and without concern for how they are enclosed. They radiate directly.
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Are you aware that some folded horns are bass-reflex ?
HF drivers (compression drivers, ribbons and dome tweeters) may be horn-loaded or direct radiating. Before you assume this is an error: there have been some recording studio monitors designed with non horn-loaded 4" compression drivers (sort of super dome tweeters).
Bag End ELF systems are probably the only non-ported/infinite baffle subwoofer made/used for live sound and although they are fairly well known, they are not widely used.
Bass-refelx and/or infinite baffle are sub (no pun) sets of the direct-radiator class, or category, of low and low-mid frequency loudspeaker enclosures.
I think that "direct radiator" is the most appropriate term for those drivers with no horns and without concern for how they are enclosed. They radiate directly.
Thanks for your reply Tom. :)
I am aware of the permutations regarding HF Drivers and how they can be loaded.
I have a pair of 4" dia. compression driver mids from a pair of three way Celestions from the 70s that fill your description of a "super dome" speaker that are not horn loaded. The cast frame woofers had butyl surounds and the tweeter was a dome unit, but I cannot remember whether they were hard or soft. They were a very accurate speaker.
I got into some pretty esoteric gear over the years including the ESS AMT Monitor, and two other pairs of ESS speakers, all of which I still own.
I also had two of the original Accustats and tube amps to go with them on a pair that predated them having serial numbers.
You can hear them strike the match that lights the cannon on the 1812 Overture!! ;D
Needless to say I have an educated ear.
I am well aware of Bag End speakers and they are not widely used in PSR because they are too inefficient a design that requires a rediculously priced proprietary ELF processor.
I designed lightweight subs,(among other things), in the mid 80s when there were no lightweight PSR subs.
I spent hours on LEAP modelling TS Parameters back then.
My "Ä" Rig is Adamson 3 MH121s per side and 2 SB1000Z per side. This rig does not see much work since venues that require a rig that big usually have their own gear.
The majority of what I do in sound now is only to facilitate my own shows.
The "B" rig gets most of the work due to the lesser demand for venue requirements which seldom exceed 300 ppl. That rig is my MRX512m monitors used as FOH up to 2 per side and up to 2 LS608s per side. My aging body loves this system!
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If you look at the graphs in the Keele paper, the none of the boxes can be called subs, as they all have a falling response below 100Hz (where their efficiency varies little from one another).
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If you look at the graphs in the Keele paper, the none of the boxes can be called subs, as they all have a falling response below 100Hz (where their efficiency varies little from one another).
You also have to remember when the paper was written and what the systems of the day were capable of.
VERY different than today.
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Thanks again to all of the knowledgeable people who unselfishly share their knowledge and experience. I am looking at buying subs for my classic rock band PA. "Back in the day" all of the high end subs were in folded horn or other type of enclosures "tuned" to amplify lower frequencies. Now it seems that half of the high end subs are in direct radiator cabinets. The direct radiator subs would certainly be easier to transport and store, but I would not want to sacrifice a significant amount of sound quality. What are the pros and cons of sub enclosures?
I have ran across more than one occasion where a folded horn subwoofer is the optimum choice. Most of the high-end horn boxes are smaller companies (and for the most part overseas). When space doesn't matter.. but available power does - the horn is usually the best box. Not much in the direct radiator world can compare to 2 blocks of 6 labs. The trend in pro audio is to go lighter, go smaller, but require more power. Horns just don't do that.
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When space doesn't matter.. but available power does - the horn is usually the best box...
+1. This is my case. Most gigs I do, outlet power IS the issue for me... and horns give MUCH higher forward output (especially outdoors), compared to my DR boxes. Efficiency is a high priority in my case, and they really perform when coupled. My large bass horns become more directional when paired, and I find it to be a big advantage to have much less bass spl behind them.