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Post by Ayton(e) on Jan 7, 2009 14:52:52 GMT -5
Hola. When I originally looked into wiring a 2x12, I came away with the impression that people basically thought they sounded the same whether the speakers were wired in series or parallel, and so I wired up in parallel, which seemed to be the norm, and forgot about it. Having learned a little since then about parallel and series generally (for example with humbucking pickups) I started to realize it was unlikely both circuits would sound the same in a guitar cab. So I dug a little deeper and came up with some interesting info. Take a look at an excerpt from The Guitar Amp Handbook:  I also ran into a post from 'pgissi' on TGP who seems to have tried both: "Series wiring- mid/upper mid and high end emphasis generally, smoother high freqs generally due to damped top end highs in the 5 to 6k range, less fizz. Additional tonal changes are slightly spongier attack and altered OD character, more complex and timbrally rich with more overtones ala the mid and top end emphasis.
Parallel wiring- low end and lower mid emphasis with more top end high sparkle or fizz, depending on the speaker and rig that can make the high end raspy or harsh to some. Low end is emphasized due to increased damping between 2 12" speakers in parallel, generallly tighter and more thump."pgissi's full TGP post, more info. The consensus seems to be that series is looser and warmer, while parallel is tighter and zingier, so I rewired my cab to series as the Competition is tight, bright and bassy. I think it's true -- going through both voice coils seems to soften the top end, bring the hi-fi ceiling down a bit, cut out some fizz, and the longer circuit might make it looser, too. I'm certainly finding it easy to play. Without being able to switch between series/parallel quickly, comparison is a little imprecise. I don't feel like I managed to roll off any bass (I always have too much) which is meant to happen, but the other characteristics are there. It might be psychosomatic but I even think it sounds different depending which speaker I put first in the circuit -- someone cleverer than me will know if this is possible or not. But yeah, just wanted to share the info. Figured if I didn't know the difference between the two, some others might not either. I wonder how Splawn 2x12s are wired by default? |
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Post by LooseCannon on Jan 7, 2009 15:28:31 GMT -5
Dude one comparison sound clip is worth a thousand words  My Splawn 2x12 is 8 ohms so I guess it's two 16 ohm speakers in parallel? If that's the case I wouldn't be able to wire it in series right? |
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Post by Ayton(e) on Jan 7, 2009 16:10:17 GMT -5
No, you'd have a 32 Ohm cab.  I have 8s so have been playing with both. |
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Post by SonicExplorer on Jan 7, 2009 17:31:58 GMT -5
The part the person who wrote the above articles is completely overlooking, and which is by FAR more responsible for the tonal differences is the output tranformer tap impedence changes.
The tests implied at the top of the thread can never truly be performed as portrayed because the only way to achieve matched impedences in the various configurations is to change speakers as well. In changing speakers the tone will change (sometimes very significantly). So again, as portrayed, the test cannot exist in reality.
Now, here's what is really happening: As the speaker configuraitons are changed, their impedence changes. The signal then exits the output transformer at different points in the winding core. This is what is effecting the tone and feel. Each amp has different variables that will yield sligtly different results, but generally speaking where the signal exits the taps of the transformer impact the tone and feel pretty much spot-on as described in the above article.
There are more variables and details involved but for now we'll stay with the simplified explanation.
So, again, what's happening here is not quite as portrayed in the article above, but rather changes to the impedence/tap paths relative to the speaker configuration.
Sonic
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Post by Ayton(e) on Jan 7, 2009 17:51:05 GMT -5
Excellent! I did hope someone with some capital-K-knowledge would find this thread.
Are you saying that what is changing the tone has more to do with the amp being set for 16 ohms when I wire in series versus 4 ohms when I wire in parallel? So theoretically a pair of 16 ohm speakers in parallel (8 ohms) would sound the same as a pair of 4 ohm speakers in series (8 ohms) if otherwise identical?
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Post by SonicExplorer on Jan 7, 2009 18:21:05 GMT -5
Excellent! I did hope someone with some capital-K-knowledge would find this thread. Are you saying that what is changing the tone has more to do with the amp being set for 16 ohms when I wire in series versus 4 ohms when I wire in parallel? So theoretically a pair of 16 ohm speakers in parallel (8 ohms) would sound the same as a pair of 4 ohm speakers in series (8 ohms) if otherwise identical? Fundamentally yes. There would still be some difference due to the configuration aspect, but it would be very minimal in comparsion to the tap/impedence aspect. Having said that, again keep in mind no two speakers are going to sound the same, and even less similar when comparing speakers of different impedences. So your question is indeed very hypothetical. Sonic |
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Post by jchan on Mar 9, 2009 16:43:15 GMT -5
You can experiment and try the different configs but wiring in series can be dangerous if you blow one speaker. You then present an open load to the output transformer and that can damage the it. Parallel is at least safer. If there is a difference in tone, its subtle. I have tried both and really don't hear anything significant. Especially when playing live where everything sounds like a controlled explosion!
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Post by Ayton(e) on Mar 10, 2009 10:27:20 GMT -5
Yep, the next paragraph in the book up there (after the highlighted one) explains that danger. It's a choice based on your application, I suppose. I'm playing at home and am sensitive to little changes, unlikely to blow a speaker at these levels, and in need of every last bit of warmth/sag. I can see how people playing live at high volume would want the protection.
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Post by DonaldDemon on Mar 10, 2009 12:04:51 GMT -5
I remember reading that thread on TGP. those dudes can get super anal about tone though.
If I have a 2x12 with SB-25's that are wired up for 8 ohms what does mean? Are the SB-25's both 16 ohm speakers wired in parallel?
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Post by MetalHeart on Mar 10, 2009 17:08:25 GMT -5
I need to take off the back of my 212 and look at my speakers. Lots of info guys  |
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Post by jchan on Mar 11, 2009 23:39:39 GMT -5
Since the SB25s only seem to come in 16 ohms, if you have an 8 ohm cab with 2 SB25s, they must be wired in parallel.
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Post by DonaldDemon on Mar 12, 2009 15:29:48 GMT -5
Since the SB25s only seem to come in 16 ohms, if you have an 8 ohm cab with 2 SB25s, they must be wired in parallel. Oh ok, thanks for the clarification. |
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Post by jchan on Mar 23, 2009 20:51:26 GMT -5
Yep, the next paragraph in the book up there (after the highlighted one) explains that danger. It's a choice based on your application, I suppose. I'm playing at home and am sensitive to little changes, unlikely to blow a speaker at these levels, and in need of every last bit of warmth/sag. I can see how people playing live at high volume would want the protection. It may be that you would have to be cranked to hear the sag differences. I did try wiring a Marshall 2x12 cab I had in series with 2, 8 ohm speakers for a 16 ohm load. I didn't hear anything noticeably different. The problem is that 8 ohm speakers have a different response than 16 ohm speakers so its very difficult to know for sure what the difference comes from. The other factor is the output tap from the amp. 2 16ohm speakers in parallel make an 8 ohm load and 2 8ohm speakers in series make a 16 ohm load. The output tap of the transformer may make some difference. Whatever the differences are, they certainly are subtle. The biggest differences come from cabinet design and speaker choices. The rest of the variables are much less significant IMHO. |
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Post by jesusdriven on Jun 8, 2009 16:53:50 GMT -5
Hola. When I originally looked into wiring a 2x12, I came away with the impression that people basically thought they sounded the same whether the speakers were wired in series or parallel, and so I wired up in parallel, which seemed to be the norm, and forgot about it. Having learned a little since then about parallel and series generally (for example with humbucking pickups) I started to realize it was unlikely both circuits would sound the same in a guitar cab. So I dug a little deeper and came up with some interesting info. Take a look at an excerpt from The Guitar Amp Handbook: I also ran into a post from 'pgissi' on TGP who seems to have tried both: "Series wiring- mid/upper mid and high end emphasis generally, smoother high freqs generally due to damped top end highs in the 5 to 6k range, less fizz. Additional tonal changes are slightly spongier attack and altered OD character, more complex and timbrally rich with more overtones ala the mid and top end emphasis.
Parallel wiring- low end and lower mid emphasis with more top end high sparkle or fizz, depending on the speaker and rig that can make the high end raspy or harsh to some. Low end is emphasized due to increased damping between 2 12" speakers in parallel, generallly tighter and more thump."pgissi's full TGP post, more info. The consensus seems to be that series is looser and warmer, while parallel is tighter and zingier, so I rewired my cab to series as the Competition is tight, bright and bassy. I think it's true -- going through both voice coils seems to soften the top end, bring the hi-fi ceiling down a bit, cut out some fizz, and the longer circuit might make it looser, too. I'm certainly finding it easy to play. Without being able to switch between series/parallel quickly, comparison is a little imprecise. I don't feel like I managed to roll off any bass (I always have too much) which is meant to happen, but the other characteristics are there. It might be psychosomatic but I even think it sounds different depending which speaker I put first in the circuit -- someone cleverer than me will know if this is possible or not. But yeah, just wanted to share the info. Figured if I didn't know the difference between the two, some others might not either. I wonder how Splawn 2x12s are wired by default? Great Thread! Thanks Ayton! |
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Post by jesusdriven on Jun 9, 2009 13:24:12 GMT -5
The part the person who wrote the above articles is completely overlooking, and which is by FAR more responsible for the tonal differences is the output tranformer tap impedence changes. The tests implied at the top of the thread can never truly be performed as portrayed because the only way to achieve matched impedences in the various configurations is to change speakers as well. In changing speakers the tone will change (sometimes very significantly). So again, as portrayed, the test cannot exist in reality. Now, here's what is really happening: As the speaker configuraitons are changed, their impedence changes. The signal then exits the output transformer at different points in the winding core. This is what is effecting the tone and feel. Each amp has different variables that will yield sligtly different results, but generally speaking where the signal exits the taps of the transformer impact the tone and feel pretty much spot-on as described in the above article. There are more variables and details involved but for now we'll stay with the simplified explanation. So, again, what's happening here is not quite as portrayed in the article above, but rather changes to the impedence/tap paths relative to the speaker configuration. Sonic I have a 2 x 12 cabinet wired in series for a 16ohm load. If I blow a speaker, or if a speaker wire somehow comes loose, will I fry my Splawn's output transformer? Will any of my Splawn's fuses protect my output transformer? |
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