front loaded bass horn without rear compression chamber?

paulspencer · 26th October 2005, 09:05 AM

I'm referring to the Rhino acoustics Bassmax horn subs:

FLH without RCC? Contradiction in terms?

This is what they have to say about it:

Quote:

# How does BASSMAXX Technology make such deep bass? The very long BASSMAXX horn provides stable driver loading down to the lowest frequencies. The Box-Free design avoids the tendencies of rapid low frequency roll-off and driver unloading that occurs below resonance in all vented boxes. It also avoids the low frequency roll-off and terrible dynamic smother associated with all sealed boxes. (This includes horn cabinets that include a sealed or vented driver sub-enclosure.) The result is, that along with their unrivaled clarity and definition, BASSMAXX technology horns provide unparalleled low frequency extension.

What do you guys think of the idea of removing the rear compression chamber? Does it actually give a better transient response, a more dynamic and uncoloured speaker?

Rademakers · 26th October 2005, 09:17 PM

Quote:

FLH without RCC? Contradiction in terms?

It is.

Skramstadt has some interesting thoughts on the sound of the RLH in his topic about the 6090 horn IIRC he created.

A drawback of a RLH is that there is an acoustic shortcut, depending on the horns length and driver position. For this reason scoops (a populair RLH design) show a gap in the frequency response around 70 -80 Hz, this also applies to for instance a transmision line. So long paths are favored.

If the path is very short and the VRC quite large than it's behauvior tends to be hybride between horn and basreflex which would deny some of the preferable horn general properties.

There are some drawbacks created by a FLH in contrast to a RLH, what exactly seems to have slipped my mind for the moment

but perhaps Skramstadt explains.

Wkr Johan

GM · 26th October 2005, 09:47 PM

Greets!

Duh!

FLH sans RCC = BLH, ergo an optimized one can have the greatest CR, BW and it's the only horn alignment I know of that yields a ~'perfect' impulse response and flattest phase/impedance (excluding inductance rise). The trade-offs are they're very long due to needing a hyperbolic 'T' (aka 'M') factor, don't make nearly as much gain as a FLH is capable of or have the benefit of the rear chamber's driver protection, and suitable midbass/LF drivers available to the DIYer are made of unobtanium AFAIK.

Not knowing any design details of the BASSMAXX, I can't comment on how close to ideal it is, but I assume it's not even close unless a number of them are stacked together to approximate an ideal termination.

FYI, the original RCA folded cinema basshorn prototype design that dominated until Altec Lansing debuted their 'A' series reflex FLH basshorns after WWII were close to an ideal BLH (as best I could tell with limited info) with the exception that the final termination was flat: http://www.audioheritage.org/html/pr...co/shearer.htm If they'd had digital time delay back then, there probably wouldn't have been an Altec 'A' series.........

GM

Coolin · 27th October 2005, 08:14 AM

GM, why do they need a hyperbolic 'T' ?

Regards,

Co

GM · 27th October 2005, 03:27 PM

Greets!

Because they can't be reactance annulled with a compression chamber.

GM

Coolin · 27th October 2005, 09:50 PM

Ah i see...

Looking at hornresponse it also looks like the reactance is very high. This seems to be bad as well although a very narrow bandwidth at cutoff...

And what if you had a very high Q driver to compensate for this?
They probably arent available that high...

Co

GM · 28th October 2005, 12:57 AM

Greets!

To compensate enough to keep peaking to a minimum like an annulled FLH, the horn has to expand very slowly from a small throat over a long distance for a low Qes driver; so yeah, the higher the Qes, the larger the throat, the faster the flare rate, the shorter its pathlength, but the larger its mouth.

GM

AndrewT · 28th October 2005, 02:30 PM

Hi Gm,
I would like to believe your conclusion but I find trouble understanding it.
Is it possible to restate it in shorter sentences and simpler language to give me a chance to follow your argument?

eLarson · 28th October 2005, 02:59 PM

Is there a FAQ? I need to see it ASAP.

paulspencer · 28th October 2005, 05:53 PM

I'm working on a bass horn faq section in the wiki ... so stay tuned, have a look and feel free to add to it, either questions and or answers found from searching

26th October 2005, 09:47 PM	#3
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	Re: front loaded bass horn without rear compression chamber? Greets! Duh! FLH sans RCC = BLH, ergo an optimized one can have the greatest CR, BW and it's the only horn alignment I know of that yields a ~'perfect' impulse response and flattest phase/impedance (excluding inductance rise). The trade-offs are they're very long due to needing a hyperbolic 'T' (aka 'M') factor, don't make nearly as much gain as a FLH is capable of or have the benefit of the rear chamber's driver protection, and suitable midbass/LF drivers available to the DIYer are made of unobtanium AFAIK. Not knowing any design details of the BASSMAXX, I can't comment on how close to ideal it is, but I assume it's not even close unless a number of them are stacked together to approximate an ideal termination. FYI, the original RCA folded cinema basshorn prototype design that dominated until Altec Lansing debuted their 'A' series reflex FLH basshorns after WWII were close to an ideal BLH (as best I could tell with limited info) with the exception that the final termination was flat: http://www.audioheritage.org/html/pr...co/shearer.htm If they'd had digital time delay back then, there probably wouldn't have been an Altec 'A' series......... GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

27th October 2005, 03:27 PM	#5
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	Greets! Because they can't be reactance annulled with a compression chamber. GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

28th October 2005, 12:57 AM	#7
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	Greets! To compensate enough to keep peaking to a minimum like an annulled FLH, the horn has to expand very slowly from a small throat over a long distance for a low Qes driver; so yeah, the higher the Qes, the larger the throat, the faster the flare rate, the shorter its pathlength, but the larger its mouth. GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

28th October 2005, 02:30 PM	#8
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi Gm, I would like to believe your conclusion but I find trouble understanding it. Is it possible to restate it in shorter sentences and simpler language to give me a chance to follow your argument? __________________ regards Andrew T.

28th October 2005, 02:59 PM	#9
eLarson diyAudio Member Join Date: Aug 2002 Location: Gaithersburg, MD	I clearly need to go to acronym class, too. Is there a FAQ? I need to see it ASAP. __________________ Would a woodchuck bother to chuck MDF?


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

27th October 2005, 08:14 AM	#4
Coolin diyAudio Member Join Date: Apr 2003 Location: Holland	GM, why do they need a hyperbolic 'T' ? Regards, Co

27th October 2005, 09:50 PM	#6
Coolin diyAudio Member Join Date: Apr 2003 Location: Holland	Ah i see... Looking at hornresponse it also looks like the reactance is very high. This seems to be bad as well although a very narrow bandwidth at cutoff... And what if you had a very high Q driver to compensate for this? They probably arent available that high... Co

28th October 2005, 05:53 PM	#10
paulspencer diyAudio Member Join Date: Sep 2003 Location: Melbourne, Australia	I'm working on a bass horn faq section in the wiki ... so stay tuned, have a look and feel free to add to it, either questions and or answers found from searching __________________ AUDIO BLOG \| Bass integration guide My work: www.redspade.com.au web design studio

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Front & rear end DUAL Back Loaded Horn + Bass Reflex Hybrid Enclosure	nickthevoice	Multi-Way	13	19th May 2009 04:09 PM
My first front and rear horn loaded fullrange design: help needed from The Wise.	maxlorenz	Full Range	20	11th July 2007 11:21 PM
HT bass horn with vented rear chamber	paulspencer	Subwoofers	2	26th February 2006 07:02 PM
Need info on designing front/rear loaded bass horns	jSisco	Multi-Way	7	4th June 2003 01:47 AM
Help! With a rear horn loaded scoop bass bin	slicemaster101	Multi-Way	38	17th October 2002 10:38 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read