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New member Username: BvanPost Number: 2 Registered: Jun-05 | tomorrow i'm loaning a sub from my local hifi store. this will be the first sub to grace my system, and as i'll only have it overnight i'm trying to anticipate integration problems in advance. i have a 2 channel system with denon 2200 universal as source. the player does have bass management for 2-channel which i'll use, setting my dynaudio 52's to 'small' at 80hz. unfortunately though,it doesnt have speaker/sub time delays in 2-chanel mode. the sub, a dynaudio 250, has phase at 0 and 180 only(not 90) while i know that i should run a frequency sweep at the crossover frequency and choose the phase setting that maximises volume, this only tells me which setting puts the sub most in phase, doesnt it? is there any way, through physical placement distances, or any other way, that i can know the sub is exactly in-phase with the speakers? i'm guessing if the sub is at the same distance from me as the speakers then all will we in phase. but minimising nodes, maximising bass, as well as the wife, might require placement somewhere else. if, say, the sub is twice the distance from me as the speakers, will in be in phase agian?(but of a different cycle?); or if i put the sub at 50% past the speakers and inverted the phase 180 might this do the same? any other ways to optimise phase? can the subs filtes slow down and delay its signal thereby effecting phase. and if anyone has any suggestions where to place sub so as to minimise axial nodes, i'd be most gratefull. i'm thinking near the front wall(not corner) as i read somewhere it might be a good idea to put the sub somewhere between the speakers. but if i put it behind the speakers near the front wall, at say 2/5ths along the front wall, that puts the sub at twice the distance from me as my speakers which are 6' out into the room. this is why i'm worrying about phase abnormalities. sorry, long post. thanks for any input anyone. b |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 5903 Registered: May-04 | http://sound.westhost.com/qb5align.htm http://www.gcaudio.com/resources/howtos/index.html More can be found by placing "subwoofer placement" into a search engine. You seem to be thinking of the signals from the sub and the signals from the satellites almost as two separate entities. The subs are reproducing the fundamentals and the satellites the harmonics of that note. And, while it may be true that the two systems are in phase electrically, the two will not be "most" in acoustic phase over a wider frequency bandwidth if they are separated in distance from your listening position. And, yes, the Xo in the system will, to some extent, affect the in phase relationship of the signals. This should be minimal in relation to other factors in the system. Deal with this small anomaly after the purchase. Much like placing a dipole speaker to even out the response from front and back wave, you are placing the sub to maximize the "most" in phase relationship of the two signals (sub & sat). With just one evening to do your audition, I would not be too concerned with tweaking the sub to the Nth degree. That process can take at least a day and sometimes more to get everything settled. My suggestion would be to place the sub only in two locations for the duration of your audition. The first location would be in line with your satellites. This will give you a reasonably smooth transition from one system to the other and allow maximum time to listen. In the time allotted you should be able to decide what you must about the sub's value. I would also give the combination a try with the satellites running full range. While not recommended for many videos systems, this arrangement can be beneficial to some music systems. Second, if time allows, I would do a quick placement of the sub according to the basic placement rule of putting the sub in the listening position and then walking the room to find the best location for the sub. After placing the sub in this location, I would run a sweep and adjust the phase control as needed. Finish your audition with the remaining time. Assure your wife the sub is there just for the evening and you will find a suitable position after the decision has been made. Unless the sub ends up six inches from the sofa where she sits (unlikely), this should allow you to make your decision and then make your adjustments after the purchase is made. Don't sweat the small stuff while you're doing this audition. I assume what you want to know is whether the sub is a worthwhile addition at the cost of the new purchase. I think this approach should tell you whether you want to spend the money or not. |
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New member Username: BvanPost Number: 3 Registered: Jun-05 | thanks jan, those sound like wise words. b |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 5937 Registered: May-04 | http://www.sonicdesign.se/subplace.html |
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Silver Member Username: NuckParkhill, Ontario Canada Post Number: 144 Registered: Dec-04 | Well Done, Jan |