4ohm drivers?
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Category: General
Forum Name: 12v Powered Systems
Forum Description: From Mini-rigs to ICE, all your low voltage audio needs here...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=76765
Printed Date: 26 March 2026 at 6:55pm
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Topic: 4ohm drivers?
Posted By: joegrind75
Subject: 4ohm drivers?
Date Posted: 03 March 2013 at 10:45pm
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Was in the pub chatting to a mate last night and I've been asked to knock up a box that will fit the back of a tricycle. Dimensions are about 55cm wide by 30/35cm deep and 60cm high max, although the shorter the better. Initial plan is a 3-way stereo, 2 bass and 2 mids in a box and a couple of CD/tweeters on a pole. If I'm using 12V TA2020's in 4 ohm and want to stay stereo, is the best option buying 4ohm drivers? Whether 2 or 3-way, the only way I can think is to use one amp per stereo pair and choose 4 ohm drivers. I can't find many decent PA speakers that are 4 ohm. Due to size I'm limited to a pair of 8" max as the width between the two rear wheels can't be more than 55cm or 21" which is too much of squeeze to fit two 10" (Could use one 10" in mono for the bass and two 8" for the mids). I've checked the Monocor/Stage Line 4ohm HiFi range, with the SP-202E, with an Fs of 42Hz and an SPL 94db. Maybe my best option? Had thought four of these, a pair each for bass and mids? The other options are to use 8 ohm drivers in parallel for the bass and tops, in mono on a channel each. It would mean I'd only require two amps, but would only get a stereo sound from the two mids. How much difference in the quality of the sound is lost by the tops being in mono? Cheers! |
Replies:
Posted By: Saturnus
Date Posted: 03 March 2013 at 10:57pm
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The 94dB SPL would be at 2W for the SP-202E. The sensitivity is 90dB/w/m if you check the datasheet. Flogging a dead horse here but you could make a tall version of the Boominator. Simply take the sketch up drawing and modify the outside dimensions except the required 30cm depth. It could be in a box of 45x30x60cm (WxDxH). There would be 2x 10" woofers on top of each other on each side in this case. It wouldn't be the first Boominator so modified to fit a bike. Usually made to fit a bike trailer. It's 4x 10" pro woofers plus 4 piezo horns. Total sensitivity is about 101db/w/m and is perfectly driven by a TA2020 amp as it's 4 ohm. |
Posted By: amlu
Date Posted: 03 March 2013 at 11:13pm
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if you manage to squeeze two 10 inches then eminence basslite... nice lightweight and efficient driver http://www.bluearan.co.uk/index.php?id=EMIS2010 |
Posted By: djkeet
Date Posted: 04 March 2013 at 2:28am
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May be worth looking at: http://www.ebay.co.uk/itm/C84-Kicker-Comp-8-inches-Car-Audio-Subwoofer-4-ohms-200-watts-Sub-Bass-Speaker-/350708324035?pt=UK_In_Car_Technology&hash=item51a7 Sensitivity even lower but it might be worth searching all the top end in-car stuff still ------------- Soundbite |
Posted By: amlu
Date Posted: 04 March 2013 at 11:35am
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car audio speakers waste of time, rarely go above 90db :( |
Posted By: joegrind75
Date Posted: 04 March 2013 at 12:15pm
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I did begin with the Boominator as an option, but my mate didn't fancy it, because it was going to be used in his shop when not on the tricycle, and he wanted the drivers facing the same way. I'm really want to use TA2020 at 12V and not TK2050 amps at 24V, so I'm looking for suitable PA drivers but can't seem to find any that are 4 Ohm. If I use 8 ohm drivers, I can't work out how to have it stereo, unless I have a pair of drivers in parallel for each left and right channel, or not have it as 3-way. So.... can you use TA2020 amps at 4ohm with a 3-way stereo setup and 8 ohm PA drivers? |
Posted By: Saturnus
Date Posted: 04 March 2013 at 12:26pm
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That's just lack of knowledge and ignorance. He can still use it in his shop. Distance to the wall just have to be around 15-20cm or more if possible. He also have to turn down the bass between 100hz and 200hz by 3-6dB if possible. The Boominator is designed for outdoors use and have an integrated bass lift in that area for that purpose. |
joegrind75 wrote:Posted By: joegrind75
Date Posted: 04 March 2013 at 12:43pm
| I appreciate your opinion, that the Boominator may be the most efficient design for these type of 12V systems, and that my friend may lack your extensive knowledge and be, as you say, ignorant, but the "brief" I have been given by him is geared towards a box that meets his aesthetic requirements as a tool to advertise his business, part of which includes a pair of horns on a pole. He has a very clear picture of what he wants, which he is as entitled to you, as you are to yours, and the Boominator does not meet his requirements. My opinion is that it would be a dull world if everyone just made Boominators. |
Posted By: Saturnus
Date Posted: 04 March 2013 at 12:58pm
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Nothing prevent you from putting midrange/tweeter horns on poles etc. All I'm saying is use the extreme efficiency and compact size of the Boominator to make the bass/mid section. It is after all 4x 10" drivers in a very compact cabinet. Remember that the Boominator is a concept design. You can follow it as closely as you want. You will however get the best result if you use the exact drivers and cabinet volume as suggested and have drivers on both sides. But I take your point and won't comment or advice any further. |
Posted By: joegrind75
Date Posted: 04 March 2013 at 3:32pm
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I appreciate your comments and respect your opinion and highly knowledgable advice. It's previous advice you have given me as to the reason why I'm trying to use TA2020 amps at 4ohm's on 12v. The problem seems to be having both a 3-way setup AND stereo together. What I'd like any answer to is... Is it possible to have a 3-way and stereo system run on TA2020 amps at 4 ohms using 8ohm drivers? My answer is: only if you use a pair of drivers in parallel for each left and right channel, so a 3-way system would need 4 for bass, 4 for mids and 4 for tops. Is there a better way? The alternatives are either 3-way mono or 2-way stereo (such as the Boominator). Am I missing anything? Thanks :) |
Posted By: mini-mad
Date Posted: 04 March 2013 at 6:44pm
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really?...... i say talk him out of stereo. if its for advertisement stereo imaging will be wasted on people that dont care that much or passers buy or WONT stop and go "... if you stand just here, you can really get a feel for the way the band has set up this track..." not realy gonna happen is it? try to talk him out of stereo and it'll cut your cost down by ALMOST half  ... just a though boys and girls. no more, no less. ------------- If it sounds like a gorilla is trying to escape, turn it down. |
Posted By: slaz
Date Posted: 04 March 2013 at 7:23pm
I agree with that when it comes to bass units - but not totally when it comes to other ranges. There are some 6x9 car speakers that work quite effectively .... often older ones e.g. my old JBL ones (although these are relatively heavy with large magnet). I'd also like to check out a few currently available ones like these :- http://www.ebay.co.uk/itm/180976532022?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649" rel="nofollow - http://www.ebay.co.uk/itm/180976532022?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649 The 95dB sensitivity is errr ..... probably optimistic - but the 40oz magnet is a good start. There are also one or two up-market car audio "manufacturers" (well - brands) that offer PA drivers in 4R versions (I mean sold as "car audio" drivers) .... tend to be expensive though. ------------- REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON |