brensabre79 Posted March 15, 2013 Share Posted March 15, 2013 Hi folks, I've designed cabinets before using just one driver, this is simple using something like the Faber Acoustical App on the iPhone or even various websites where you put in the T&S parameters of the driver and tune the cab and port accordingy. However, i need to design a cabinet that will use 4x12" drivers. Neither the app or the websites I have used offer this capability and I'm not sure its as simple as just quadrupling the volume for one driver is it? I don't have WinISD because I'm Mac based. SO can anyone help? Cheers Bren Quote Link to comment Share on other sites More sharing options...
bremen Posted March 15, 2013 Share Posted March 15, 2013 [quote name='brensabre79' timestamp='1363357464' post='2011756'] However, i need to design a cabinet that will use 4x12" drivers. Neither the app or the websites I have used offer this capability and I'm not sure its as simple as just quadrupling the volume for one driver is it? [/quote] Happily, yes it is that simple. Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 15, 2013 Author Share Posted March 15, 2013 Wow OK, thanks! what about the port though? Quote Link to comment Share on other sites More sharing options...
bremen Posted March 15, 2013 Share Posted March 15, 2013 [quote name='brensabre79' timestamp='1363373126' post='2012086'] Wow OK, thanks! what about the port though? [/quote] Ah, the port. If you calculate the port for one speaker, then four such ports will work. Presumably that means you can then replace them with one of the same length but for times the area. I'm not 100% sure about that though. I could model a random speaker in WinISD and check...hang on... Quote Link to comment Share on other sites More sharing options...
bremen Posted March 15, 2013 Share Posted March 15, 2013 What drivers are you using, what size cab and what port frequency do you fancy? Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted March 17, 2013 Share Posted March 17, 2013 The volume of the cab is 4x that of a single speaker as bremen says. the port however tunes the volume of air in the cab so you need to recalculate. With 4x12" speakers you will be shifting a lot of air and so the port will need to be a decent size or you will get wind noise from the port. You should be able to find an online port calculator easily enough but if it is aproblem give us the volume of your cab and the tuning frequency and someone will give you port dimensions. It might be worth building a shelf port for a speaker like this Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 18, 2013 Author Share Posted March 18, 2013 Thanks folks, I'm currently experimenting with drivers to get the best results, its a bit of a strange design this one, for a strange purpose (can't tell you too much as we're still in R&D) A shelf port would probably make life much easier but I've no idea how to do those, having been exclusively cardboard tube with previous designs! I've got a basic modelling Excel spreadsheet to do the calculations, but not sure how to do shelf ports, multiple drivers. Currently whatever drivers I use I'm getting some crazy Xmax results below 30Hz - in that it goes way beyond the capabilities of the driver. (like 15cm!) I'm also quite restricted in terms of the cabinet volume. Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 18, 2013 Author Share Posted March 18, 2013 [quote name='bremen' timestamp='1363374167' post='2012119'] What drivers are you using, what size cab and what port frequency do you fancy? [/quote] Current favoured drivers are Fane Sovereign 12-500LF Volume 131Litres Frequency - trying to get 30Hz - 40Hz just to even out the low end. but getting crazy Xmax as above... Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 18, 2013 Author Share Posted March 18, 2013 OK more precisely 38.49Hz for the Port. Could anyone tell me how to do a shelf port then please... Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 18, 2013 Author Share Posted March 18, 2013 This is the Xmax / Cone excursion issue with a 20cm dia. port at 32.12cm length. Should I be worried about this? Quote Link to comment Share on other sites More sharing options...
bremen Posted March 18, 2013 Share Posted March 18, 2013 [quote name='brensabre79' timestamp='1363613877' post='2014728'] This is the Xmax / Cone excursion issue with a 20cm dia. port at 32.12cm length. Should I be worried about this? [/quote] You'll always get large excursions below resonance. But its a usefully low frequency, use a steep high pass filter and all will be well. Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 18, 2013 Author Share Posted March 18, 2013 OK Thanks Bremen. Any ideas on the shelf port? Cheers Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted March 18, 2013 Share Posted March 18, 2013 The shelf port is pretty self explanatory and you'll see it in a lot of commercial cabs so go take a look. The port is the full width of the cab and a few centimetres high. At the bottom of the baffle there is a shelf inside the cab. This traps a body of air just like a circular port. The area of the port and it's depth are part of the design. The advantage is no need to cut any extra holes in the baffle and the use of the full width of the cab usually means a space saving. the disadvantage is tht a shelf fixed in place is hard to change once the glue is dry. It is easier to trim a cardboard tube if you need to change the tuning. Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 19, 2013 Author Share Posted March 19, 2013 Thanks Phil, I understand, but how do I calculate a shelf port dimensions? Is it true that it is not a simple case of calculating a round port volume and making the shelf port the same volume? Is it affected by the fact that three sides of the port are also sides of the cabinet? I heard somewhere that it needs to be shorter because of this, reducing the volume of the port. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted March 20, 2013 Share Posted March 20, 2013 The tuning depends upon the area of the port and the length, so a round port of 20 sq cm and a shelf port of 20sq cm would need to be the same length for the same tuning. WinISD gives the option of rectangular ports but if your program gives you round ones then calculate the area and away you go. For example a 10cm diameter port has an area of 78.5 sq cm so if your cab were 39.25 cm wide the port would need to be 2cm high. Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 20, 2013 Author Share Posted March 20, 2013 OK thanks Phil, I think I got it now. Thanks for all your help with this, its a really unusual build and the first prototype has not performed well being required to go down to 20Hz cleanly, without chuffing, and in a fixed size box! Much appreciated. Quote Link to comment Share on other sites More sharing options...
Balcro Posted March 20, 2013 Share Posted March 20, 2013 Hi brensabre, This is intriguing. From what I've seen elsewhere on this forum, particularly from Bill Fitzmaurice, there is an emphasis on "displacement" to achieve volume in the bass. I would have thought an xmax of 5mm would be a bit on the low side for a loudspeaker that is required to go down to 20Hz cleanly!! It would/should also probably have a low fundamental resonance (fs). I've just played about on winISD with a loudspeaker driver set in a 4 x 12 configuration. With an xmax of 8mm and a 100w input. It achieves -2.3dB @ 40Hz, -6dB @ 30Hz and -17dB @ 20Hz. Xmax is only exceeded at 19Hz. The only problem is that the enclosure has an initial recommended volume of 300 litres!! Fun and games on my part, I know, but the 5mm xmax in your spreadsheet looks to be part of the weakness along with the Fane's "fs" of 50Hz. More to discuss? Balcro Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 21, 2013 Author Share Posted March 21, 2013 Thanks Balcro Yes it was quite limiting with those drivers and a fixed box size. I came into this project halfway through to solve some issues and I was applying my limited knowledge of instrument cabinets to a non-instrument problem - more of a Hi-Fi one. A helpful chat with Alex at Barefaced has set me along the right path now. He was really very helpful! I've gone for a complete redesign now using a sealed box and Peerless drivers. Quote Link to comment Share on other sites More sharing options...
6v6 Posted March 21, 2013 Share Posted March 21, 2013 [quote name='brensabre79' timestamp='1363357464' post='2011756'] I don't have WinISD because I'm Mac based. [/quote] There are several ways around this - I run Linux (Fedora) and WinISD works fine under wine (an open-source windows emulator, which also works on Mac by the looks of it): http://wiki.winehq.org/MacOSX You could also install a windows VM and run WinISD inside that, but then you'd need a windows licence, so I prefer to use wine wherever possible. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted March 21, 2013 Share Posted March 21, 2013 Oh Good, I'd completely missed out on the 20Hz issue and I didn't want to break it to you, frankly you don't need to go that low for most hi-fi unless you listen to a lot of organ music with 32foot stops. Glad you've sorted your problem. Yet more Kudos to Alex. Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted March 21, 2013 Author Share Posted March 21, 2013 Thanks folks, Yes Alex also suggested VM WinISD option. I had a look at Wine looks complicated to install to be honest! Anyway, I think the speaker thing is sorted. Thanks everyone for your help with this. Quote Link to comment Share on other sites More sharing options...
olivermetal Posted April 11, 2022 Share Posted April 11, 2022 is it ok to use 9pcs 100W peak 3way speakers in series parallel connection in a sigle cabinet connected to a 1000W RMS amplifier? Quote Link to comment Share on other sites More sharing options...
olivermetal Posted April 11, 2022 Share Posted April 11, 2022 Pls you can reply me at my email [email protected] Quote Link to comment Share on other sites More sharing options...
itu Posted April 11, 2022 Share Posted April 11, 2022 What is that you are actually looking for? What is your "3 way speaker"? Peak wattage tells very little about the elements, the tuning or the suitability to bass use. Please be a bit more specific, and you sure get decent answers. Quote Link to comment Share on other sites More sharing options...
olivermetal Posted April 11, 2022 Share Posted April 11, 2022 (edited) I only ask if the setup can function and generate desired output in a given the specs.. Edited April 11, 2022 by olivermetal Quote Link to comment Share on other sites More sharing options...
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