Dual driver subs impedance
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=5826
Printed Date: 27 March 2026 at 11:02am
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Topic: Dual driver subs impedance
Posted By: TomD
Subject: Dual driver subs impedance
Date Posted: 22 July 2006 at 2:03pm
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Hi
If I want to build some 2x15" subs, and want the completed cabinet to end up at 8 ohms, what's the best way of going about this? I could either use 2 4ohm drivers in series, or 2 16ohm paralleled. If, as an example, each driver was 1000w, what would the total rated power of the cabinet be in each case? |
Replies:
Posted By: JD01
Date Posted: 22 July 2006 at 3:56pm
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In any case the rating will be 2000W.
The better way is to use two 16 ohms drivers in parallel. This is more reliable.
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Posted By: kevinmcdonough
Date Posted: 23 July 2006 at 7:18am
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I understand that by using parallel wiring the speakers will be more reliable, as one will still continue to play even if the other stops, but could this also be a downfall? If one speaker suddenly stops working and the other is playing, then the playing one will suddenly find itself plaing with double the cabinate volume behind it which, i would guess, would mean it may blow as well? At least in series, although you'd loose the volume from both drivers, you'd save the other driver from blowing? kev |
Posted By: Ben_Lawrance
Date Posted: 23 July 2006 at 10:40am
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If one of your drivers blows whilst connected in parellel, the the amplifer would then see 16ohms as opposed to 8ohms. Therefore reducing the power into the cab. An amp that drives 2000w into 8ohms (is not just a big f**king amp) will drive 1000w into 16ohms. How many amps out there will drive 2KW into 8ohms anyway? Surely you'll be bridging the amp?
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Posted By: ceharden
Date Posted: 23 July 2006 at 12:00pm
| When I built some twin 15" subs recently, I used seperate chambers for each driver so that if one blows the other will continue working normally. The dividing piece also braces the cabinet in the middle. |
Posted By: TomD
Date Posted: 23 July 2006 at 12:45pm
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They were hypothetical values, I'd probably be using something like 2x500/800w 16ohm parallel to make a total cabinet power handling of 1000/1500 watts.
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Posted By: JD01
Date Posted: 23 July 2006 at 1:41pm
I got one here....
Sometimes the coil of the speaker doesn't break the circuit when burnt, but short it. That means if you put two 4 ohm speakers in serial, and one fries, the other one would still run... at 4 ohms! So the ONE remaining speaker will get double the power the two speakers would get together, which would be around 3000W (for ONE speaker!). So it will blow easily.
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Ben_Lawrance wrote:Posted By: super-hero
Date Posted: 23 July 2006 at 4:18pm
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I seem to recall reading somewhere that parallel is better, because of the affect it has on the amplifiers damping factor.
Someone else will know the specifics of this. ------------- I'm not an animal, I'm a human being. |
Posted By: JD01
Date Posted: 23 July 2006 at 9:48pm
| This is just a rumor without any scientific background. It has no effect on the damping factor. I can't belive there are actually engineers believing that nonsense. |
Posted By: TomD
Date Posted: 24 July 2006 at 10:06am
But if this happened while in parallel, the amp will short. I'm not really intending to be pushing drivers to breaking point, I was just confirming that two 1000w drivers in parallel would in fact result in a 2000w configuration. |
Posted By: norty303
Date Posted: 17 August 2006 at 1:10pm
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I think its more relevant that the change in cab volume for the one remaining driver will have an effect.
When i blew my BP6 drivers and looked at the VC's, both had evidence of burnout, however only 1 had any marks to indicate hitting back plate. I presumed that once one went the other also burnt but spent some time over excursing beforehand ------------- My laser stuff: http://www.facebook.com/SubsonicSystems" rel="nofollow - Frikkin Lasers |
Posted By: Tom Umney
Date Posted: 17 August 2006 at 1:57pm
| Two seperate chambers in the same box would be the key to using a dual driver sub. |
Posted By: JD01
Date Posted: 17 August 2006 at 8:57pm
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Of course, that situation in parallel would short the amp, but a good amp will stand it by shutting down the channel or going into thermal on that channel... So at least the second speaker will live....
Also, two 1000W drivers in serial will result in a 2000W configuration. No difference in that matter...
In a dual driver BP6 the loss of one driver will be even more dangerous than in BR type boxes.
In general, if you go for SPL seperate back chambers are mandatory. If you go for sound, a single volume has a slight advantage because some tolerance issues will be lowered.
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