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-   -   Difference between Super Scoop and Folded Horn Subwoofers (http://www.diyaudio.com/forums/subwoofers/231894-difference-between-super-scoop-folded-horn-subwoofers.html)

ClackS02 12th March 2013 10:40 AM

Difference between Super Scoop and Folded Horn Subwoofers
 
Hello Guys!

I am fairly new to the construction of PA equipment, i have done a lot of work with Car Audio builds.

I am going to be performing at a couple of outside parties (fields) this summer and i am looking at getting some bass bins for my gear! It seems to me the best way to go would be either folded horn or super scoop!

However, i havent a clue what design would be good for me?

I currently have 2x JBL JRX 115 which are great! but i will need more energy especially if im outside.

I plan on building two bins using 2 x 18" Pa Bass Drivers around 1000 watt RMS with 4" voice coils.

Can you guys help me please!!!!!!!!

Superscoop:
http://www.performing-musician.com/p...YPAcabs_04.jpg

Folded Horn:
http://www.virtualdj.com/image/62537...horn%20sub.gif


PLEASE HELP!

Steve
-DubRoach Production
DubRoach Weekly HOME

Xoc1 12th March 2013 02:52 PM

Your JBL JRX115 are fairly flat to 100Hz so there are many subs that will work.
The front loaded folded horn design you posted is not really suitable as it is designed to be used in a corner which tend to be in short supply outdoors. Front loaded horns tend to be used in multiples to produce high SPL levels - Think very big and loud.
The Scoop design can work and are certainly loud - They tend to have a big hole in the response about 80Hz so if you choose to build one take care that the frequency response will match your JBL mid tops
Speakerplans.com
A Scoop bin is closely related to a Tapped Horn. Tapped horns have a smoother response that would match you speakers better. Plenty of designs around here that would be suitable!;)
How much noise do you want to make?
It you want to avoid trouble and keep the neighbours happy you might be better off with a pair of reflex ported subs - they certainly would be the most compact option.

ClackS02 12th March 2013 03:00 PM

Quote:

Originally Posted by Xoc1 (Post 3407517)
Your JBL JRX115 are fairly flat to 100Hz so there are many subs that will work.
The front loaded folded horn design you posted is not really suitable as it is designed to be used in a corner which tend to be in short supply outdoors. Front loaded horns tend to be used in multiples to produce high SPL levels - Think very big and loud.
The Scoop design can work and are certainly loud - They tend to have a big hole in the response about 80Hz so if you choose to build one take care that the frequency response will match your JBL mid tops
Speakerplans.com
A Scoop bin is closely related to a Tapped Horn. Tapped horns have a smoother response that would match you speakers better. Plenty of designs around here that would be suitable!;)
How much noise do you want to make?
It you want to avoid trouble and keep the neighbours happy you might be better off with a pair of reflex ported subs - they certainly would be the most compact option.

This is very accurate and helpful info thanks!!!

I would want to use these for a large outdoor party this summer (to give you an idea of size) for about 500-600 people. So i would want as much as possible!

What do you mean by Scoop design ???? this term confuses me! Could you give me an example? maybe an image ? that would be great!

I dont need to worry about neighbors ;) They all have pretty much no hearing at all anyway !!!

more10 12th March 2013 03:46 PM

Scoop is a nickname for JBL 4530 (single driver) and 4520 (dual driver) back loaded horns:

http://i151.photobucket.com/albums/s.../4520jbl-1.jpg

http://www.audioheritage.org/vbullet...1&d=1247364982

They look like big scoops.

Superscoop is the 18" driver version from speakerplans. Also a back loaded horn.

All backloaded horns have a design problem with cancellation when the output from the horn is out of phase with the front of the driver. At about 3 times the lowest frequency of the horn. But the backloaded horn will give 3 dB more output at the low end compared to a front loaded horn. The JBL 4530 has the first cancellation at about 150 Hz:

http://img149.imageshack.us/img149/8316/jbl4530ua1.gif

A good compromise would be to build (or buy) several backloaded horns with a bit shorter horn path, like the JBL 4530. The JBL 4530 will be useful from about 50 Hz to about 140 Hz. You can stack them lying down in two rows with the driver end toghether to achieve "long throw". I believe 8 of these will achieve pretty good output outdoors.

more10 12th March 2013 03:53 PM

Since you are in UK, you should be able to get you hands on cheap Martin front loaded horns.

http://www.dancetech.com/aa_dt_new/a..._x_15_horn.jpg

ClackS02 12th March 2013 04:01 PM

Quote:

Originally Posted by more10 (Post 3407588)
Scoop is a nickname for JBL 4530 (single driver) and 4520 (dual driver) back loaded horns:

http://i151.photobucket.com/albums/s.../4520jbl-1.jpg

http://www.audioheritage.org/vbullet...1&d=1247364982

They look like big scoops.

Superscoop is the 18" driver version from speakerplans. Also a back loaded horn.

All backloaded horns have a design problem with cancellation when the output from the horn is out of phase with the front of the driver. At about 3 times the lowest frequency of the horn. But the backloaded horn will give 3 dB more output at the low end compared to a front loaded horn. The JBL 4530 has the first cancellation at about 150 Hz:

http://img149.imageshack.us/img149/8316/jbl4530ua1.gif

A good compromise would be to build (or buy) several backloaded horns with a bit shorter horn path, like the JBL 4530. The JBL 4530 will be useful from about 50 Hz to about 140 Hz. You can stack them lying down in two rows with the driver end toghether to achieve "long throw". I believe 8 of these will achieve pretty good output outdoors.

This is a great help! However, my only worry is having the speaker on show..! Im in the UK, and that means a lot of rain!

Would you say there is anything bad against Folded Horns like the following:
MX-F18B - MX SERIES - Wharfedale Pro
http://www.wharfedalepro.com/Portals...MX/MX_F18B.jpg

more10 12th March 2013 04:24 PM

One drawback is the cost. 1400 apiece.

There is no information on how many you will need to get flat response outdoors. You will most probably need at least 4 for one sub.

ClackS02 12th March 2013 04:26 PM

Quote:

Originally Posted by more10 (Post 3407644)
One drawback is the cost. 1400 apiece.

There is no information on how many you will need to get flat response outdoors. You will most probably need at least 4 for one sub.

Thats not quite what i meant, i mean the design, the folded design, if i built my own would there be anything you recommend/avoid ?

The building part isnt a problem, just dont want to waste time and money if im not happy with it in the end!

Appreciate your Help !

more10 12th March 2013 04:59 PM

A properly designed front loaded horn will sound better than a back loaded horn or a tapped pipe. It will have less output though, or be bigger than a back loaded horn or tapped pipe. If you want quality go for front loaded horn.

The warfedale is a front loaded horn.

You will need to decide on how low you want your system to go. The size and cost for a 20 Hz system is probably 4 times compared to a 30 Hz system.

Find a few plans, Speakerplans.com, PA Systems, sound systems, speaker boxes, live Sound - Dancetech, match them to you needs. A good plan should have advice on which drivers to use, and how many you will need for outdoors use.

Precision Devices makes excellent low cost drivers and are based in the UK.

tb46 12th March 2013 05:16 PM

Hi ClackS02,

You can use Hornresp by David McBean to answer many of your questions.

Hornresp

Without a tool like this you will be talking mainly in generalities (which is fine too. :-)). You need to share what you are actually going to use these subwoofers for, and with (the more detail, the better).

Regards,


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