fletcherkane Posted January 28, 2005 Share Posted January 28, 2005 HI everyone, forgive this non-audiophile question. On the rear of my downfiring MTX sub there is a switch that allows me to switch the phase 180 degrees. I think I understand the theory behind it. (For instance, I know that sound cancelling headphones use sound that is 180 degrees out of phase to cancel noise.) However, for the life of me, I can't hear ANY difference between the two settings. I have tried moving it around the room etc, but have found no audible difference. What should I listen for when tring to set this correctly? Thanks in advance for your help... Quote Link to comment Share on other sites More sharing options...
dodger Posted January 28, 2005 Share Posted January 28, 2005 In phase means Poitive (+) to Positive + from Amplifier to speaker terminal, Negative to Negative (-). having one connected the way the terminals are marked is in phase, reversing is out of phase if the other if reversed. In phase means drivers move back and forth at the same time. Out of phase means one going forward, one going back. If it's a single sub from two channel it can (in high price models) analze if one side is wired out of phase and correct. Others reverse phase on one channel. Listen for more bass in one setting, thin almost echo type, reverb maybe, sound. Try reversing leads on one of your mains in a 2 channel setting. That will give you the effect and then more knowledge of what to listen for. There my be a channel in your sun out of phase and changing phase only changes the proble side. Good Luck, dodger Quote Link to comment Share on other sites More sharing options...
fletcherkane Posted January 28, 2005 Author Share Posted January 28, 2005 I think you may have answered my question dodger, and then again maybe not... I have my sub hooked up in a traditional 5.1 HT. The sub is hooked up via a digital coax to the LFE output on my receiver. Seeing that I am not using the positive and negative terminals, maybe the switch doesn't even come into play? It is not an expensive sub, but it performs very well when paired with my Forte mains. (The Forte's don't need much assist from the sub.) Quote Link to comment Share on other sites More sharing options...
dodger Posted January 28, 2005 Share Posted January 28, 2005 Then I doubt that the phasing may be off, thus the phase switch still reverses but with it hooked as is it would not be of notice. The changing on your mains was only a short thing so as to hear 1 in, 1 not. Quote Link to comment Share on other sites More sharing options...
ygmn Posted January 28, 2005 Share Posted January 28, 2005 phase switch.....changes wether the woofer cone moves out or in one a positive portion of the analog signal..... you use this to have the bass output of sub closely match timing from main speakers....which tend to be in a different location....this helps to get rid of BASS cancelation from room effects due to the sub bass sound coming from a different part of the room versus the mains.... Some subs (Klipsch RW series) have a PHASE knob which makes for infinite adjustment of phase from 0 to 180 degrees...... To see which position is better....play something with good BASS that is pretty constant....like a test DVD or test CD... then sit in fave listening spot.....and close eyes....while someone switches the phase switch...(or adjust knob if have one) until the BAss sounds the best to you.... this may make the bass sound worse in some other positions... HTH Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 29, 2005 Share Posted January 29, 2005 if you know what a basic sin wave looks like. and you do a phase shift of 180 degrees on that what it will do is move the sin wave 3.14159265441028204 (impressive i know that all from memory lol) units or pi units over to the left and what that will do then is the sin wave will start at 1 units on the vertical axsis, (or whatever the amplitude is) instead of 0. thus doing exactly what the above post said... and you won't notice any difference in the sound unless the signal coming out of your amp is out of phase Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 29, 2005 Share Posted January 29, 2005 ohh also there are many manufacturers that build there amps out of phase on purpose ie conrad johnson, why i am not sure.... but anyways Quote Link to comment Share on other sites More sharing options...
the ^*BeholdeR*^ Posted March 13, 2005 Share Posted March 13, 2005 sorry for the revival of thread...but i wanna know how does a phase switch work if the sub has 2 drivers? thnx! Quote Link to comment Share on other sites More sharing options...
sivadselim Posted March 13, 2005 Share Posted March 13, 2005 ---------------- On 3/13/2005 8:03:47 AM the ^*BeholdeR*^ wrote: sorry for the revival of thread...but i wanna know how does a phase switch work if the sub has 2 drivers? thnx! ---------------- it works the same way. both those sub drivers should be in phase with one another already. unless the sub is designed to have one adjustable phase driver and the other not; which is doubtful. what sub is it? Quote Link to comment Share on other sites More sharing options...
the ^*BeholdeR*^ Posted March 14, 2005 Share Posted March 14, 2005 hey sivadselim, dont mind...but i hav a humble setup! Altec Lansing 641 speaker system - subwoofer with two 16.5 cm front-firing, long-throw drivers operating at 109 Watts@4 ohms@10% THD@16-105Hz(-3dB) Single Channel Loaded (92 Watts@4 ohms@1% THD@18-100Hz(-3dB) Single Channel Loaded); with two bass-reflex ports at the rear. the sub's in a corner with the ports facing a wall, 0.5 m away and the drivers facing a hollow wooden cabinet, 0.45 m away....so the walls & the cabinet engulf a C-shaped enclosure for the sub! the sub has a 'subwoofer phase' in-out switch....for a long time, it was in the "in" position...the bass then used to boom/muddle for few audio passages, which i disliked. i changed the sub position throughout my 5 m x 4 m room; but the 'C' corner still sounded the best! finally, i turned the subwoofer phase switch to "out"...the bass came out wonderfully tight, well-defined & distinctively clear for the same audio passages, which earlier sounded boomy/muddy!! i want to know what exactly happened?? can you investigate? Thanks... Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted March 14, 2005 Share Posted March 14, 2005 When you changed the position on the phase switch you put the sub more in "time" with the mains. The subs timing in relation to the mains was off. It's similar in effect to wiring one speaker out of phase with another. Correct the wiring and the speakers sound much better. Quote Link to comment Share on other sites More sharing options...
the ^*BeholdeR*^ Posted March 15, 2005 Share Posted March 15, 2005 hi CECAA850....i really didnt get wut u meant in ur reply! sorry, its kinda woolly up there.. wut i feel is this (.... n its just my imagination! ) - for ported bass-reflex subs, the actual effect comes from the port (i say so, coz i hav seen subs with speaker drivers inside the enclosure, with only the port opening outside!) n from wut i hav learnt in these forums - 1. the port uses the air driven by the 'backward' movement of the driver 2. a in-out phase switch inverts the driver movement. so where the driver would normally move out, itll move in; when the phase is changed by 180° for the same signal....thus changing the direction of bass comin from a bass-reflex sub (in my case, opposite directions, since the ports r at the rear....) now, in my speaker setup, the sub drivers face a hollow wooden cabinet n the ports face a solid concrete wall....did this setup aid in improvin bass on changin phase from 'in' to 'out'??? lemme know.... Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted March 16, 2005 Share Posted March 16, 2005 Basically all speakers including subs create sound waves. Don't get caught up in wether a sub is sealed, ported or passive radiator. All the phase switch does is alter when the wave is created in relation to the main speakers. Hope this helps. Quote Link to comment Share on other sites More sharing options...
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