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LeonBryant

Phase of Woofer in Forte IIs

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Greetings Kilpsch family!

 

I just put Crites crossovers and new tweeter diaphragms in my Forte IIs. I should have paid more attention to the way the speaker wires were connected, I noted the phase of the squawker, but not the woofer.  :P

 

I know the tweeters are correct, because they are marked. The squawker was still connected in one of the speakers so I am pretty sure that's right. Does the phase of the woofer make any difference? My friend has an identical pair and his seem to get richer bottom end. He seems to think it does not matter, so I thought I'd put this to the experts.

 

I'd appreciate any help on this.

 

Thanks!

 

Leon

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If you think this has something to do with your speakers, you can take one of yours to his place and play one of his and one of yours in mono. You will notice the difference right away.

 

The buddy's low end may have more to do with his stereo or the room itself. Perhaps you should consider your stereo equipment or room treatments or even speaker placement. These factors make all the difference when it comes to low frequencies.

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You'd have more of a bass issue if you wired one woofer out of phase with the other.

 

Bass is really room dependent.  If you're really that curious, do as mustang guy recommends and carry one of yours over to his house.

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I am no Klipsch speaker expert but here is what I would instead of carrying a speaker to another place. Dince the schematic shows the + input connected to the + of the driver. Take a 9 volt battery and while watching the woofer connect the battery to the leads coming from the woofer briefly. The woofer will be pushed out if phase is correct, it will pull in if incorrect. So again if the speaker pushes out make note which wire is connected to the battery positive and thats your woofer positive.

-Cindy

Edited by CindyJarvis
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I am no Klipsch speaker expert but here is what I would instead of carrying a speaker to another place. Dince the schematic shows the + input connected to the + of the driver. Take a 9 volt battery and while watching the woofer connect the battery to the leads coming from the woofer briefly. The woofer will be pushed out if phase is correct, it will pull in if incorrect. So again if the speaker pushes out make note which wire is connected to the battery positive and thats your woofer positive.

-Cindy

just a reminder to folks to maintain polarity when testing,  pos at the battery to pos at the speaker.

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All Klipsch speakers (and any speaker in general, that I am aware of, with the caveat there are a couple of physical configurations where it is necessary to "reverse" the polarity) will have the woofers wired with positive polarity (a positive voltage applied to the positive terminal will result in a positive excursion of the cone, away from the magnet structure). The wavelengths of the bass frequencies are such that if any woofer in the system (Klipsch or otherwise) is out of polarity with another woofer, the bass response will suffer greatly.

 

As an aside and not to nitpick at all, we are discussing polarity here, and not phase (although the two are often used interchangeably in polite conversation). Polarity is frequency independent. Phase varies with frequency.

 

If you are saying that the terminals don't seem to be marked, look closely at the terminals on the woofer. I think they used a red Sharpie marker to mark the positive terminal, back in the day. It may have faded or been rubbed off, but might still be slightly visible if you look hard enough.

Edited by Old_Klipsch_Guy
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All Klipsch speakers (and any speaker in general, that I am aware of, with the caveat there are a couple of physical configurations where it is necessary to "reverse" the polarity) will have the woofers wired with positive polarity (a positive voltage applied to the positive terminal will result in a positive excursion of the cone, away from the magnet structure). The wavelengths of the bass frequencies are such that if any woofer in the system (Klipsch or otherwise) is out of polarity with another woofer, the bass response will suffer greatly.

 

As an aside and not to nitpick at all, we are discussing polarity here, and not phase (although the two are often used interchangeably in polite conversation). Polarity is frequency independent. Phase varies with frequency.

 

If you are saying that the terminals don't seem to be marked, look closely at the terminals on the woofer. I think they used a red Sharpie marker to mark the positive terminal, back in the day. It may have faded or been rubbed off, but might still be slightly visible if you look hard enough.

Many JBL drivers are the opposite.

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All Klipsch speakers (and any speaker in general, that I am aware of, with the caveat there are a couple of physical configurations where it is necessary to "reverse" the polarity) will have the woofers wired with positive polarity (a positive voltage applied to the positive terminal will result in a positive excursion of the cone, away from the magnet structure). The wavelengths of the bass frequencies are such that if any woofer in the system (Klipsch or otherwise) is out of polarity with another woofer, the bass response will suffer greatly.

 

As an aside and not to nitpick at all, we are discussing polarity here, and not phase (although the two are often used interchangeably in polite conversation). Polarity is frequency independent. Phase varies with frequency.

 

If you are saying that the terminals don't seem to be marked, look closely at the terminals on the woofer. I think they used a red Sharpie marker to mark the positive terminal, back in the day. It may have faded or been rubbed off, but might still be slightly visible if you look hard enough.

Many JBL drivers are the opposite.

 

That is very true, especially on the vintage components. While I happen to believe that there just wasn't an industry convention at the time, there was a story floating about that they did this so that if you were to use a JBL cabinet with any other brand, it would sound horrible and all the bass would go away. So, it became a selling point that if you had JBL, you should continue to buy JBL... or suffer the consequences.

 

Just a story, as far as I know. Maybe true. Maybe not.

 

ETA: A few more thoughts on the JBL convention. Keep in mind that JBL was founded only 20 years after Rice and Kellogg first invented the direct radiator loudspeaker. While the "positive voltage = negative excursion" convention might have simply been the result of a coin flip, I suspect that he might have just been emulating the dynamics of the audio chain (i.e. a positive breath = negative excursion of the microphone diaphragm should "logically" cause a negative excursion of the loudspeaker cone). Of course, the same logic from another point of view is that a positive breath by the vocalist should result in a positive breath from the speaker. But, that is sheer speculation on my part. Just something to make you go hmmmmmmmmmm.

Edited by Old_Klipsch_Guy

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