Building a low-end sub for outdoor use

CCU · 06:06 PM

Hi all you wonderfull DIY'ers

I'm building a new and BIGGER setup for turing Denmarks festivals

The new one is quite large, 1 meter wide and 3 meters long.
I am building 2 DR 280 speakers from Bill Fitzmaurices website and i need 1 or 2 subwoofers to go with them. just to ad a litte UMF

Our old speaker setup used 8 Velleman VDSSP8/8 bas units and a couple of piezo tweeters. Velleman nv

I've been thinking about building a small horn for them. obviouslythere are NO designs for them, because they are ridiculously cheap/low-end

My question is. do you know of any design for a small'ish horn that those drivers might work in.

I've been thinking about building 2 of these, but 60cm wide, so that i can contain 4 units
Speakerplans.com

Will this give anything near a diesent performance,

I don't look for anything under 45hz of usable output, simply because it is a low power rig og outdoor

Would really apriciate some input for you guys

PS here's a picture of the old setup

CCU · 2nd March 2010, 06:12 PM

I've found more T/S specs for them than is listed on the website.

Impedance (Z) 8
Resonant frequency (fs) 35Hz
Max. frequency range f3-6,000Hz
Music power 350WMAX
Power rating (P) 250WRMS
SPL (1W/1m)Â 91dB
Suspension compl. (Cms) 0.25mm/N
Moving mass (Mms) 65g
Mech. Q factor (Qms) 4.95
Electr. Q factor (Qes) 0.66
Total Q factor (Qts) 0.58
Equivalent volume (Vas) 43 l
DC resistance (Re) 6,4
Force factor (BxL) 12.6
Voice coil induct. (Le) 0.8mH
Linear excursion (XMAX) ±6mm

And i have no idea of how accurate they are!!

BP1Fanatic · 2nd March 2010, 07:01 PM

What is the Sd or hole cut out diameter?

CCU · 2nd March 2010, 07:12 PM

The cut out hole i 17.6cm. if i understand the question.
The casket has a diameter of 20.5cm

BP1Fanatic · 07:23 PM

Quote:

Originally Posted by CCU

I've been thinking about building 2 of these, but 60cm wide, so that i can contain 4 units
http://www.speakerplans.com/index.php?id=hd15horn

You need to model it in Hornresp to see if 4 of those subs will perform with good results in that modified HD15.
http://hornrespdb.com/showparameters...nresp Database

Horn Parameters
Ang : 1,0 x Pi Eg : 2.83 Rg : 0 Fta : 16.51

S1 : 544.8 S2 : 722.16 L12 : 27.38 F12 : 0
S2 : 722.16 S3 : 1054.92 Con : 15.25 F23 : 0
S3 : 1054.92 S4 : 1785.57 Con : 15.36 F34 : 0
S4 : 1785.57 S5 : 2206.16 Con : 8.97 F45 : 0

Chamber parameters
Vrc : 52 Fr : 40 Vtc : 20000
Lrc : 40 Tal : 4 Atc : 1982.4

CCU · 2nd March 2010, 07:27 PM

thanks

I'm not really sure how to use that program, but i'll give a try

BP1Fanatic · 2nd March 2010, 07:46 PM

Quote:

Originally Posted by CCU

The cut out hole i 17.6cm. if i understand the question.
The casket has a diameter of 20.5cm

Sd = 17.6 x 17.6 x 0.7854 = 243.29cm^2.

CCU · 01:08 PM

i think i've done it right

Multiplied the sd by 4 for the 4 drivers and added the volume to the rear champer

here's how it looks...

CCU · 3rd March 2010, 01:10 PM

for a low-end build i don't think i looks to bad

with usable output to 40hz

letsbangout · 3rd March 2010, 01:25 PM

When I was new to Hornresp, I also made the mistake of trying to derive new values for parameters like Sd, for example, by multiplying the Sd by the number of drivers. Hornresp works much better if you use the built-in Driver Arrangement wizard. Go to the Input Parameters, fix all of the parameters as they would be for a single driver, then click Tools and Driver Arrangement. Tell it how many drivers you will have in series, then how many of those groups you will have in parallel. You want to do it this way because the electrical parameters, for example, will determine the usable bandwidth and the upper/lower end of your design.

What kind of horn are you trying to design for these?

2nd March 2010, 06:00 PM	#1
CCU diyAudio Member Join Date: Apr 2007 Location: Kgs. Lyngby	Building a low-end sub for outdoor use Hi all you wonderfull DIY'ers I'm building a new and BIGGER setup for turing Denmarks festivals The new one is quite large, 1 meter wide and 3 meters long. I am building 2 DR 280 speakers from Bill Fitzmaurices website and i need 1 or 2 subwoofers to go with them. just to ad a litte UMF Our old speaker setup used 8 Velleman VDSSP8/8 bas units and a couple of piezo tweeters. Velleman nv I've been thinking about building a small horn for them. obviouslythere are NO designs for them, because they are ridiculously cheap/low-end My question is. do you know of any design for a small'ish horn that those drivers might work in. I've been thinking about building 2 of these, but 60cm wide, so that i can contain 4 units Speakerplans.com Will this give anything near a diesent performance, I don't look for anything under 45hz of usable output, simply because it is a low power rig og outdoor Would really apriciate some input for you guys PS here's a picture of the old setup Last edited by CCU; 2nd March 2010 at 06:06 PM. Reason: Added a picture

3rd March 2010, 01:07 PM	#8
CCU diyAudio Member Join Date: Apr 2007 Location: Kgs. Lyngby	i think i've done it right Multiplied the sd by 4 for the 4 drivers and added the volume to the rear champer here's how it looks... Last edited by CCU; 3rd March 2010 at 01:08 PM. Reason: added some pictures

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2nd March 2010, 06:12 PM	#2
CCU diyAudio Member Join Date: Apr 2007 Location: Kgs. Lyngby	I've found more T/S specs for them than is listed on the website. Impedance (Z) 8 Resonant frequency (fs) 35Hz Max. frequency range f3-6,000Hz Music power 350WMAX Power rating (P) 250WRMS SPL (1W/1m)Â 91dB Suspension compl. (Cms) 0.25mm/N Moving mass (Mms) 65g Mech. Q factor (Qms) 4.95 Electr. Q factor (Qes) 0.66 Total Q factor (Qts) 0.58 Equivalent volume (Vas) 43 l DC resistance (Re) 6,4 Force factor (BxL) 12.6 Voice coil induct. (Le) 0.8mH Linear excursion (XMAX) ±6mm And i have no idea of how accurate they are!!

2nd March 2010, 07:01 PM	#3
BP1Fanatic diyAudio Member Join Date: Jan 2009 Location: Columbus, Ohio	What is the Sd or hole cut out diameter?

2nd March 2010, 07:12 PM	#4
CCU diyAudio Member Join Date: Apr 2007 Location: Kgs. Lyngby	The cut out hole i 17.6cm. if i understand the question. The casket has a diameter of 20.5cm

2nd March 2010, 07:27 PM	#6
CCU diyAudio Member Join Date: Apr 2007 Location: Kgs. Lyngby	thanks I'm not really sure how to use that program, but i'll give a try

3rd March 2010, 01:10 PM	#9
CCU diyAudio Member Join Date: Apr 2007 Location: Kgs. Lyngby	for a low-end build i don't think i looks to bad with usable output to 40hz

3rd March 2010, 01:25 PM	#10
letsbangout diyAudio Member Join Date: Sep 2008	When I was new to Hornresp, I also made the mistake of trying to derive new values for parameters like Sd, for example, by multiplying the Sd by the number of drivers. Hornresp works much better if you use the built-in Driver Arrangement wizard. Go to the Input Parameters, fix all of the parameters as they would be for a single driver, then click Tools and Driver Arrangement. Tell it how many drivers you will have in series, then how many of those groups you will have in parallel. You want to do it this way because the electrical parameters, for example, will determine the usable bandwidth and the upper/lower end of your design. What kind of horn are you trying to design for these?