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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 => SR Forum Archives => LAB Subwoofer FUD Forum Archive => Topic started by: Holger Schmidt on October 28, 2007, 05:05:46 am

Title: LAB with open back chamber
Post by: Holger Schmidt on October 28, 2007, 05:05:46 am
Hello to all,

perhaps a stupid question. ( it is my first post, so... Smile

what happens, if i open the back chamber of the driver to the horn?
and if this is a bad idea, what happens if i tune the back chamber to have a additional reflex loading into the horn mouth?

Best regards

Title: Re: LAB with open back chamber
Post by: Ted Olausson on October 28, 2007, 09:11:25 am
Holger wrote on Sun, 28 October 2007 10:05

Hello to all,

perhaps a stupid question. ( it is my first post, so... Smile

what happens, if i open the back chamber of the driver to the horn?
and if this is a bad idea, what happens if i tune the back chamber to have a additional reflex loading into the horn mouth?

Best regards




http://mywebsite.bigpond.com/dmcbean/
Title: Name Policy
Post by: Mac Kerr on October 28, 2007, 09:51:38 am
Holger, please go to your profile and change your alias to your real full name as required by the posting rules clearly displayed at the top of the page.

Mac
moderator
Title: Re: LAB with open back chamber
Post by: Holger Schmidt on October 29, 2007, 07:53:10 am
Thanks Ted,

Hornresponse is a fine tool, but i think i can not simulate this.
Or you can tell me how i must simulate the horn, with the hole of the back chamber 65cm away from the Horn mouth.

Holger

Title: Re: LAB with open back chamber
Post by: Tim McCulloch on October 29, 2007, 11:49:17 am
Last January we had a "FrankenLab" sub brought in by Raj Sookraj.  It had no access covers and was not the full 45" depth.  We gave it a TEF sweep but had no "stock" LABsub to compare it to.

The TEF plots are on the Danley Sound Labs site (in the forums, I think).  You have to register before you can download, but it's free.

Before you do so, you might want to go to the Product Review forum here to find the threads about the NYC Sub Shootout (Jan 29 & 30, 2007) and the ensuing discussions.  Basically, the test "room" was a smaller (than I was envisioning) club in NYC and the room had a significant influence of the measurement process.  It's valid insofar as you can compare the speakers tested there, but those tests are not valid for comparisons to speakers not measured in the same space.

Have fun, good luck.

Tim Mc

ps.  What the problem with using the LAB Sub as designed?
Title: Re: LAB with open back chamber
Post by: Ted Olausson on October 29, 2007, 12:34:32 pm
There is an option called "combine" in hornresp where you enters the distance between the front and back.
It was added to simulate backloaded horns but it works just the same with frontloaded, also the reflexports distance to the horn is possible to simulate.
Read the helpfile, a lot of options like this is covered there.
Title: Re: LAB with open back chamber
Post by: Holger Schmidt on October 29, 2007, 01:10:52 pm
Hi,

i know about the FrankenLab, but this is a different design.
I have thought, Raj´s LAB have no cover at the sides.
And my idea was to open the back chamber in the Horn....
...more like a tappered horn with a complete open back chamber.
And before i cut my LAB, i have hoped anybody have simulate this design, or can help me.

TED, i check this out, thanks.

and the target of my doing is to understand the unction of this Horn a little bit better.
I have build  LABs ( Version 4)(it is mine)with nearly no front chamber, with the hope, to can use it a little bit higher.
i can not say it is better than the original, because i can not compare. But i love it. An no trouble with it until yet Smile

regards
Holger