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Discussion Starter #1
What are the cheapest (reasonable) sounding 18" drivers available in Austalia? Where can I get them from? I tried Acoustic Concepts but they have problems with their supplier - and the 15" Tumult driver they had (now gone) was very expensive ($1150!).

Alternatively, what are the pros/cons to importing from overseas e.g. the USA Parts Express "Dayton DCS450-4 Classic 18" Subwoofer 4 Ohm" - they seem very cheap - are they any good e.g. as good as Peerless drivers?

I was hoping for the $600 (Australian) price range...

Thanks.
 

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For $600 Canadian you can get a pair of IXL-18.4's shipped to your door. These have 22mm xmax while the Dayton DCS450-4 has 8.5mm. Therre is no comparison. Here's a link to the subs.

http://testbed.mach5audio.com/index-1.html

This is a little over your budget, but for a pair of decent 18's, this is as cheap as it gets.
 

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You may want to contact Elemental Designs. I'm not sure that they do international shipping but it's worth a shot. Their 190v2 18's are normally 199$ shipped in the US and there are a lot of people are using them.
 

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You may want to contact Elemental Designs. I'm not sure that they do international shipping but it's worth a shot. Their 190v2 18's are normally 199$ shipped in the US and there are a lot of people are using them.
I checked with Elemental Designs and a pair of 19Ov.2 Subwoofers shipped to Australia is U.S. $750.
 

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Discussion Starter #5
Thanks for the replies. I don't know if it makes any difference but I'll be using the driver(s) for a home installation. I was planning on just building one sub but what do most people do - a pair? If I build one sub then these drivers look within budget, although the freight is more than the cost of the driver! Oh well, I think that's what we're stuck with here in Australia. Do you know if these drivers would be suitable for a down firing sonotube (I think the 190v.2 is)? My main aim is to build something which will go down to 20hz flat (with room gain). My room is about 21' x 14'.

Cheers,
Blue
 

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Is the Mach5 IXL18 300$ shipped to AUS?! If that's the case then it's a no brainer and go with a pair of those.
 

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Discussion Starter #9
At that price I could afford to buy a pair of Mach 5s depending upon a suitable amp - I was looking at purchasing a Behringer EP2500. Can this amp be used to power two subs? If so, what would be a better way to go for the money:

a) x2 18" Mach 5 driven sonotubes = $500 US +shipping
b) x1 18" soundsplinter sonotube = $425 US + shipping (i.e. I presume a better quality driver than the Mach 5s)

I'll only really use the sub for movies. Also, I have a sub at the moment, a 12" Peerless XLS + 2 12" passive radiators in a fifty litre box, with 240 (8ohms)/350 (4ohms) watt plate amp. I'm not that happy with performance (runs out at 24hz and not loud enough - seems to clip at higher volumes: -8db at the receiver and about 45% gain on the sub amp) so I really want a significant improvement on my current sub.

Also, could I use my current plate amp with an 18" driver?

Thanks for your suggestions :)
 

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x2 18" Mach 5's move 9 liters of air. x1 18" SoundSplinter moves 6.5 liters of air. You'll get a significant improvement with either one, a liitle more with a pair of Mach 5's. 350 watts to a single sub of either brand would never reach the potenial these subs have. The Behringer EP2500 would get the job done.
 

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Discussion Starter #11
Excellent - and in terms of sound quality do you think the Mach 5s would be as good as the 12" Peerless XLS I have presently? And also, which would be better, the 2 mach5s in separate enclosures (e.g. x2 sonotubes) or both drivers one large box, possibly downfiring (would be slightly cheaper using one box but I think the sonotubes may be easier to make?). And also vented versus sealed?

Cheers,
Blue
 

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I've never heard the 12" Peerless XLS so I can't say. I do own a pair of Adire 12" Shivas and a pair of Ascendant Audio 15" Atlases, and I can say the IXL-18's take it to another level. I built my IXL-18's in seperate enclosures due to placement issues. If you want to keep the cost down you can build 2 sonotubes. They will be big though, recommended size is 12.4 cubic feet net tuned to 15hz. Here's a link to my build to give you an idea on box size.

http://www.hometheatershack.com/forums/diy-subwoofers-sealed-ported/8554-mach-5-audio-ixl-18-4-build.html
 

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Discussion Starter #13 (Edited)
Thanks Mike. I'd like to try the sonotubes - due to ease, cost, and small footprint - but my ceiling is only 7.6' high. I too am in a concrete basement. Any reason why you went for the boxes as opposed to the sonotubes (I think I've asked you this question at another forum!)? I tried modelling the driver in winISD but it seemed to recommend about 197 litres at 19hz tuning (-3db at 20hz) which I think works out to about 4 foot sonotubes at 1' 10" interior width. Does that seem correct? What kind of amp are you using to drive your Mach5 subs?

What is a good tuning frequency for these subs - you used 15hz? Is there much material being recorded on DVDs at that level - or is it mostly above 20hz?

Also - what's a good magnatude frequency response curve in WinISD? And I can't get any readout for Max SPL with the Mach 5 driver - what's going on?

Cheers,
Blue
 

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Is there much material being recorded on DVDs at the level - or is it mostly above 20hz?
I'll second that request! Anyone know if some analyses were done on blockbusters DVD to show the spectral content at subsonic frequencies?

My subs are tuned to 22 Hz and I have to use a second order high pass at 20 Hz. Despite that steep subsonic filter, I can assure you that the room shaking stuff is there in full force!

You could say I question the usefullness of a linear response to 10 Hz! :)
 

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If you want to use the subs for movies, then the EBS alignment is the way to go. The recommended box size is 350 liters tuned to 15 hz. When modelling in WinISD the goal is to keep the port length under 36 inches and to keep the air speed at a reasonable level. To make it all work together, 12.4 cubic feet tuned to 16 hz works with a 8 inch diameter port 36 inches long. With an input power of 750 watts the airspeed is 23 m/s at 14 hz.

There is a lot of material under 20hz on todays DVDs. Tuning the subs to 16 hz will allow you to experience this. If you can't get any readout for Max SPL in WinISD then you are missing a parameter. To help you design a sonotube, here is a link to an excellent program from Collo.

http://www.subwoofer-builder.com/sonosub.htm

To figure out port length, use this calculator. It is more accurate then WinISD.

http://www.psp-inc.com/

If you need help with anything, just ask.
 

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Discussion Starter #16
These were all the parameters I have (from the website).

T/S Parameters

Fs = 17.7 Hz
Re = 3.4 Ohms
Qes = 0.39
Qms = 5.59
Qts = 0.37
Mms = 434.3 grams
Rms = 8.69 kg/s
Cms = 0.184 mm/N
VAS = 274.1 litres
Sd = 1029.2 cm2
Xmax = 22 mm
Cone Diameter = 36.2 cm

I think I'm missing the BL that WinISD asks for (whatever that is). Do you happen to have it or know where I can get it from?

With the design specs you have given me, would I need anything like a highpass filter?

Thanks for the links. I have the sonotube software and it looks great.
 

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Blue, you need to enter Pe (max power) in the driver data for the MaxSPL graph to function. Depending on your alignment and frequency, excursion limited power handling may actually be higher than the published thermal power.

There is definitely content recorded lower than 20hz. "A lot" is a relative term meaning different thing to different people. There are threads at HTF and AVS with spectral graphs of various scenes. SVS has published a few in their FAQ section as well. In most of the graphs I looked closely at, when there was decent content <20hz, there was usually equal or more signal in the 20-40hz range. Perceptually, I'm not sure if one would really notice the absence of <20Hz content with that much 20-40Hz action going on. You can get the couch/walls/etc. shaking with 40hz...I don't think my butt's a precise enough measurement device to differentiate what frequency is actually causing the shaking. :hsd:

Another interesting tid bit on low frequency perception. I read an article once, sorry, it was back in the early '90s before everybody put everything they know up on the 'net, although it may be out there now. Anyway, the article was explaining some research where someone found our brains would/could perceive the fundamental of a frequency (music in the research) based on the presence of the harmonic(s). Memory's fuzzy now, but I would assume it was specific harmonics that were required...say 1st and/or 2nd...doubtful that something like a 5th harmonic only could allow a brain to regenerate the fundamental. I'm pretty sure it wasn't Bose related since even back then I had a healthy disdain for marketing/legal action instead of performance to identify the superior product.

-Brent
 

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Discussion Starter #19
Thanks Brent. So that begs the question - should I tune for max extension (below 20hz) or max spl (from 20hz)? Is there a THX standard for extension? Also, how important is it to get a flat curve for the transfer function magnitude & how does that curve relate to max SPL and which one is most important (I know, probably both). In fact, I've got no idea what to do with WinISD - e.g. the best tuning for my application - lost!

Blue
 

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Discussion Starter #20
Anyone know the Pe (max power) for the Mach 5 IXL 18.4? Or does any one know where I can get the full specs for the driver?


Sorry, I found it: 800 watts
 
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