ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 2 3 [4] 5   Go Down

Author Topic: Direct versus Folded Horn Sub enclosures  (Read 47851 times)

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 9534
  • Atlanta GA
Re: Direct versus Folded Horn Sub enclosures
« Reply #30 on: December 21, 2011, 10:03:04 AM »

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.
Logged
A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Glenn A Williams

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 51
Re: Direct versus Folded Horn Sub enclosures
« Reply #31 on: December 21, 2011, 01:10:15 PM »

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.
« Last Edit: December 21, 2011, 05:30:14 PM by Glenn A Williams »
Logged

Stuart Pendleton

  • Full Member
  • ***
  • Offline Offline
  • Posts: 187
  • Colonial Yorktown, VA
Re: Direct versus Folded Horn Sub enclosures
« Reply #32 on: December 21, 2011, 01:16:26 PM »

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
« Last Edit: December 21, 2011, 01:40:14 PM by Stuart Pendleton »
Logged

Glenn A Williams

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 51
Re: Direct versus Folded Horn Sub enclosures
« Reply #33 on: December 21, 2011, 05:40:40 PM »

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.
« Last Edit: December 21, 2011, 05:59:04 PM by Glenn A Williams »
Logged

Stuart Pendleton

  • Full Member
  • ***
  • Offline Offline
  • Posts: 187
  • Colonial Yorktown, VA
Re: Direct versus Folded Horn Sub enclosures
« Reply #34 on: December 21, 2011, 06:36:12 PM »

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. 
Logged

Scott Bolt

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1765
Re: Direct versus Folded Horn Sub enclosures
« Reply #35 on: December 21, 2011, 06:41:10 PM »

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

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).
Logged

Tom Stone

  • Newbie
  • *
  • Offline Offline
  • Posts: 31
Re: Direct versus Folded Horn Sub enclosures
« Reply #36 on: December 21, 2011, 07:55:39 PM »

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)
Logged

Tom Young

  • Global Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 620
Re: Direct versus Folded Horn Sub enclosures
« Reply #37 on: December 22, 2011, 08:05:58 AM »

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.
Logged
Tom Young
Electroacoustic Design Services
Oxford CT
203-888-6217

Glenn A Williams

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 51
Re: Direct versus Folded Horn Sub enclosures
« Reply #38 on: December 22, 2011, 06:15:28 PM »

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!

« Last Edit: December 22, 2011, 06:58:16 PM by Glenn A Williams »
Logged

Tim Padrick

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 927
  • Indianapolis
    • T.P. Audio
Re: Direct versus Folded Horn Sub enclosures
« Reply #39 on: December 24, 2011, 08:43:50 PM »

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).
Logged

ProSoundWeb Community

Re: Direct versus Folded Horn Sub enclosures
« Reply #39 on: December 24, 2011, 08:43:50 PM »


Pages: 1 2 3 [4] 5   Go Up
 



Site Hosted By Ashdown Technologies, Inc.

Page created in 0.037 seconds with 24 queries.