Need a plan for a 8" bass speaker |
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laricot
New Member Joined: 19 March 2015 Location: france Status: Offline Points: 8 |
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Posted: 02 May 2015 at 4:43pm |
Hello I am reading this forum for longtime ago and ,
I recently build some speaker box for a little 12V sound system, I have just wanded something to listen music whith my friend and I don't a super high quality and efficient sound system It run power from a 12V 7.5 SLA batterie and a car amplifier . some pic: http://www.hostingpics.net/viewer.php?id=987191IMG20150319203609.jpg - http://www.hostingpics.net/viewer.php?id=168319IMG20150319203830.jpg - http://www.hostingpics.net/viewer.php?id=677243IMG20150319203726.jpg - The problem is: the bass speaker is made from an old driver find in some garbage so it don't sound good and i want to make another one . So I am seaching for plan for a 8" bass speaker ? I have found a driver wich is in the spec i wanted: http://www.faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=401030100 so i have try to make a plan whith WINISD but I amnote sure if the result are reliable? http://www.hostingpics.net/viewer.php?id=675658winisd.png - So if someone have any idea of where find some plan for 8" bass speaker it would be an great help for me :D sorry if i have made huge english mistake i'm not an enlish speaker!! Thank for everybody who can help me |
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mini-mad
Old Croc Joined: 13 July 2012 Location: london Status: Offline Points: 6903 |
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You could try a transmission line tuned to 50-55hz.
You should be able to fold that to fit into a fair sized back-pack and get a good response. |
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If it sounds like a gorilla is trying to escape, turn it down.
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markie
Old Croc Joined: 31 October 2005 Location: Sunny Liskeard. Status: Offline Points: 4570 |
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Keep it simple, 15-20 litre reflex box and pust one of these in:-
http://www.bluearan.com/index.php?id=VLTBM2201&browsemode=manufacturer |
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If it's got wheels or tits it's gonna cost a fortune
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laricot
New Member Joined: 19 March 2015 Location: france Status: Offline Points: 8 |
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Hello
Thanks for your responses ! -mini-made: the idea of transmission line can be interesting. But I don't know if I have the required woodworks skill for this type of enclosure! It seem to be more complex than a classic vented enclosure? -markie: So do you think that a 20 litre box is a "standard" size for this kind of enclosure?? Thank you for the link but this driver is a bit overpriced, I am on a short budget preject... |
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Hemisphere
Old Croc Joined: 21 April 2008 Status: Offline Points: 2272 |
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Volt driver is only 92dB/watt anyway, it's not for 12v.
I think your original plan was fine, it'll make a decent noise and you can't really go far wrong with a reflex - Try and design the box so you're able to adjust the port after testing the driver, so you can get it sounding exactly how you want it. I'd consider tuning the box a little higher with a peak around 60-80Hz. You could easily squeeze an extra 2dB of sensitivity and then cut your bass higher like 60Hz instead of 50Hz. In real world terms that'll give you nearly double the battery life, which you're gonna need if you plan to run bass from a 7.5ah SLA. Not to mention the boost in total SPL.
Edit: If you want to fit it in a backpack it'll need to be much higher tuned.. Remember a litre is like a carton of juice, 40 litres is a big box Edited by Hemisphere - 03 May 2015 at 10:12pm |
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laricot
New Member Joined: 19 March 2015 Location: france Status: Offline Points: 8 |
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Thank you Hemisphere for your responce Big smile If 92Db/Watt isn't sufficien. Having an 95Db/watt driver is it good? Ok thank for your advices! considering that, I had remake some winisd calculation : Do you think it can be ok? Can I change the shape of the box (an keep the same volume) whithout modifing the sound produced? |
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Hemisphere
Old Croc Joined: 21 April 2008 Status: Offline Points: 2272 |
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Looks like a good balance to me but I'm not an expert. I made a reflex box with a similiar - even slighter higher - frequency response and it had plenty of bass for most uses. Your peak is around 120Hz which will give it a powerful kick. 95dB for an 8 inch driver is good enough - very few have more than this (those which do usually have a weak bass response) 3dB = 100% increase in sound power (the amount of watts not the volume level), so a 92dB driver would need 200% as much battery power for the same volume.
The box can be any shape within reason - Apparently using the golden ratio (1.618) is a good idea if possible, for the best sound out of a square box. So if the box is 10cm deep make it 16.2cm wide and 26.2cm high. Visually this looks good too.
Edited by Hemisphere - 05 May 2015 at 1:17am |
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laricot
New Member Joined: 19 March 2015 Location: france Status: Offline Points: 8 |
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Okay again thank you for yor advices I can't have the "golden ration" to fit in my back, If it is not very important I think it can be ok whithout it! I considere to use10mm MDF . Is it okay for this box? |
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lutkeveld
Young Croc Joined: 23 September 2013 Location: The Netherlands Status: Offline Points: 517 |
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I would use 9 or 12mm plywood
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laricot
New Member Joined: 19 March 2015 Location: france Status: Offline Points: 8 |
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Hello!!Big smile
First of all, thank's to all the people whitch gave me advice for the building of this boxes. http://www.hostingpics.net/viewer.php?id=551247IMG51071.jpg http://www.hostingpics.net/viewer.php?id=150646IMG201508101530311.jpg - Finaly it's loaded with a monacor spa 8 pa http://www.monacor.de/en/products/speaker-technology/pa-bass-speakers/8/spa-8pa/ But now i want to upgrade my amp because my amp currently is from a car radio witch only give 50w into 4ohm.....LOL I consider to buying this: http://www.ebay.fr/itm/Boost-DC-DC-Converter-12V-60V-to-12V-80V-600W-10A-Power-Supply-Step-Up-Module-/351429676553?hash=item51d2d74e09 http://store.sure-electronics.com/audio/audio-amplifier-board/medium-power/aa-ab32189 The problem is I don't know the quality of this "boost converter" and I don't trust the "600W" rating!!! Anyone have more informations ? tested something similar? And the other problem is on the sure's website they say that the duties are not included in their price. And I don't know how to deal with it? I come from france so if anyone from france or from europe have already buy something from sure do it have some problems?? Thanks for your answer and sorry for the english mistake. Edited by laricot - 07 September 2015 at 8:32pm |
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studio45
Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3863 |
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There are videos on Youtube showing a similar boost converter being load-tested, and apparently the 600 watt rating is more or less true - the maximum CURRENT available at the output is 10 amps, so the power developed depends on the voltage you have selected. If you set it to 60 volts, then 60x10= 600 watts. If you run it at 48 volts, 48x10=480 watts. This is true for all boost converters; the limiting factor is how much current the diode and inductor can handle.
The Sure amp board is a great piece if kit, and will perform much better than your car radio. I use the 2x300 watt boards and they are really good. I paid about £15 to import two amps and two power converters from China to UK, which I just paid to Sure, and they sorted it all out for me. The package was marked as "audio amplifiers" with the real total price on it, so I assume it was all legitimate - or I would have got a secondary bill from UK Customs by now....
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Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
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