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Archive Home >> All About Speakers(1 2 3 4 5 6 7 8 9 10 11 12 ) >> Phase/Invert Switch?(6 posts)


Phase/Invert Switch?Ace H
Apr 14, 2001 6:40 AM
On a subwoofer what does the "phase/invert" switch do?
re: Phase/Invert Switch?HTguy
Apr 14, 2001 6:58 AM
Just what it says, it inverts the phase. It changes the positive and negative points of the soundwave by 180 degrees. The reason it is included is because some equipment and/or recordings invert the phase and this switch gives you the opportunity to switch it back. Just place it in the position that sounds best, usually off or 0 degrees.
re: Phase/Invert Switch?Ace H
Apr 14, 2001 7:42 AM
Pardon my lack of knowledge regarding this but I'm still not quite sure I understand what you mean. Could you be a little more "elementary" with your explanation?
Also....since the object of using a sub is to get "low" frequencies, I noticed some subs have both low and high "cut" adjustable controls. I can understand setting the "high" frequency range, but I don't quite see the point in having a "low" frequency control. For example: a sub with a Variable high-cut frequency, 50 -- 170 Hz when set to 50HZ the sub will take over all sounds from 50HZ and below this I fully understand....so how does the "low" cut come into play here?
re: Phase/Invert Switch?HTguy
Apr 14, 2001 12:28 PM
Sound is created by a speaker when its cone moves out and back. To invert the phase means to switch positive and negative waveforms, which means that when the speaker cone would be moving out for positive, it will be moving back to negative if the phase was reversed. The reason phase invert switches are put on electronics is because sometimes certain pieces of equipment invert phase at their output, or the recording might have been recorded thru equipment that inverts the phase. Having it on a piece of electronic gear as an option gives you the chance to switch it back. If you can't tell the difference, don't worry about it. You need a high resolution system to hear the difference, it should sound a little smoother and better defintion with the phase switch in the right position. The right position is usually 0 degrees or phase invert off. But If you have any equipment that inverts phase or a recording that does it would sound better in the 180 degree or invert on position. Again, it will be a very slight difference and if you can't tell than don't worry about it. Most equipment doesn't have this option. The reason you cut the frequency in the other direction is to take the load off your monitor speakers, with the sub handling the lowest frequencies, the monitors need not waste energy on frequencies below say 50 hz. This way they can perform their job better without the stress of having to hit the low notes.
re: Phase/Invert Switch?Ace H
Apr 14, 2001 1:28 PM
Thanks HT Guy now I understand the phase/invert issue.
Now about this sub and frequency issue...I have a Yamaha RX-V800 A/V receiver which has an LFE cutoff of 90 db. Let me know if I am correct here. What this means is that when I use a sub with this system, my Yamaha will send all signals 90 db and below to the LFE channel HOWEVER if I have a sub with a crosserover of 50 - 170 Hz would it be ok to set the sub at 50 (since this is below the 90 db cutoff of my receiver)? Since the sub will be taking over for everything from 50Hz and lower, assuming I have bass management set up correctly (LFE is being sent to BOTH mains and sub and mains set to large - as I have floor standing speakers) it appears I will still be missing some frequencies between 90 db and 50 db specifically 89 - 49 db...that range between where the receiver cuts off (90 db) and where the sub picks up (50)? Since the receiver is cutting out the frequency at 90 db, the "missing" frequencies are not going to my mains either. I hope I'm being clear here.

P.S. The crossover control on the sub only has the minimum (50) and maximum (170) points marked....one would have to guess at points in between.
re: Phase/Invert Switch?HTguy
Apr 15, 2001 6:57 AM
I'll assume you mean 90 hz, not 90 db. You again need to read the manual to determine how your bass management is setup. If the freq. to the mains is cut at 90 hz. I wouldn't set the sub crossover at 50 hz., because like you said you then would be missing information between 50-90 hz. If you have unmarked settings between 50-170 hz, is it possible to extrapolate? For ex: 170-50=120, if there are 4 score marks between maybe each represents 30 hz. I would go the lowest over 90 that I could that way I know I'm not missing any information. If your manual says you definitely lose the frequencies below 90 to the sub, the sub needs to pick up all this info. Do you have a manual for the sub? It may say in there what the other unmarked crossover points are. If not try extrapolating. I would want the whole range covered, so you want to set the crossover at least at 90 hz. If you have to, to be sure use the 170 hz setting, the sub shouldn't be recieving info from 90-170 anyway so your subs amp won't be wasting energy trying to reproduce these frequencies.
 


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