SWL Posted March 7, 2014 Share Posted March 7, 2014 I kept taking measurements and adjusting from them never could get it to sound like I wanted it to... Glad you got some positive results. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 8, 2014 Author Share Posted March 8, 2014 Yes finally I did but, I will bet the curve isn't going to look good. The room must be doing something in the area in question to make the curves look the way they do!!! Quote Link to comment Share on other sites More sharing options...
davis419b Posted March 8, 2014 Share Posted March 8, 2014 Sometimes all that measuring equipment is not very useful in the being due to the learning curve. What type of sub is this? What everyone is saying for the most part is set the subwoofer crossover at 50 and set the main speakers crossover at 50 Hz. How do you get the main crossover down to 50 Hz ? Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 8, 2014 Author Share Posted March 8, 2014 Sometimes all that measuring equipment is not very useful in the being due to the learning curve. What type of sub is this? What everyone is saying for the most part is set the subwoofer crossover at 50 and set the main speakers crossover at 50 Hz. How do you get the main crossover down to 50 Hz ? For me it is to use my EQ and HPF it provides... Quote Link to comment Share on other sites More sharing options...
mustang guy Posted March 8, 2014 Share Posted March 8, 2014 This is a long shot, but have you tried bypassing the Yammy, and going straight to the amp to see if that may be causing the slope for some reason? Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 8, 2014 Author Share Posted March 8, 2014 This is a long shot, but have you tried bypassing the Yammy, and going straight to the amp to see if that may be causing the slope for some reason? No i haven't but I am about certain it is not. I may try this just to be sure but, in either case the EQ is staying in the system. Matter of fact I have another one I ca try as well. Quote Link to comment Share on other sites More sharing options...
bracurrie Posted March 8, 2014 Share Posted March 8, 2014 Another thought. I also had my son adjust the phase on the sub slowly while listening to some bass drum music that extended down to 30 Hz or lower. What I was listening for was the attack when the drum was struck. As some point the attack became cleaner and then as he kept turning it went muddy again. Backed the knob to the clean sweet spot and loved the bass of my system augmented by the sub. I believe, as an amateur audio enthusiast, that because you are dealing with such long wavelengths its vital to time align the sound from the sub with the sound from the mains, thus the 0-90 degree phase adjustment knob on many self powered subs. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted March 8, 2014 Share Posted March 8, 2014 This is a long shot, but have you tried bypassing the Yammy, and going straight to the amp to see if that may be causing the slope for some reason? No i haven't but I am about certain it is not. I may try this just to be sure but, in either case the EQ is staying in the system. Matter of fact I have another one I ca try as well. Like I said, long shot. Yammy gear is great, but you might have a bad one.... I bought a Yamaha P7000S amp late last year and had to send it back. They replaced it happily. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 9, 2014 Author Share Posted March 9, 2014 This is a long shot, but have you tried bypassing the Yammy, and going straight to the amp to see if that may be causing the slope for some reason? No i haven't but I am about certain it is not. I may try this just to be sure but, in either case the EQ is staying in the system. Matter of fact I have another one I ca try as well. Like I said, long shot. Yammy gear is great, but you might have a bad one.... I bought a Yamaha P7000S amp late last year and had to send it back. They replaced it happily. Well i am curious so I may pull out the REW tomorrow!!! Quote Link to comment Share on other sites More sharing options...
Ski Bum Posted March 9, 2014 Share Posted March 9, 2014 Watch the crossover region (your at 80 high and low now, correct?) using REW as you adjust the phase of the sub. And use your ears, as bracurrie did. Bet you notice some correlations. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 9, 2014 Author Share Posted March 9, 2014 Watch the crossover region (your at 80 high and low now, correct?) using REW as you adjust the phase of the sub. And use your ears, as bracurrie did. Bet you notice some correlations. Yes 80 high and low, I am not sure what you mean by using REW to adjust the phase of the subs??? Explain please. Quote Link to comment Share on other sites More sharing options...
Ski Bum Posted March 9, 2014 Share Posted March 9, 2014 Explain please. Not using REW to change the phase, but rather using it to measure the mains individually and separately from the subs, particularly since you adjusted your filters. You can use those results to guestimate sub lp freq, level, and phase. Then you listen, measure, tweak. If your room doesn't obscure it too much, you can actually measure (and hear) the notch at the crossover freq when phase is out of whack. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 9, 2014 Author Share Posted March 9, 2014 Explain please. Not using REW to change the phase, but rather using it to measure the mains individually and separately from the subs, particularly since you adjusted your filters. You can use those results to guestimate sub lp freq, level, and phase. Then you listen, measure, tweak. If your room doesn't obscure it too much, you can actually measure (and hear) the notch at the crossover freq when phase is out of whack. Can you look at the measurement and see if the phase is out? If so can you show me how it's done? Quote Link to comment Share on other sites More sharing options...
mustang guy Posted March 9, 2014 Share Posted March 9, 2014 Yes you can see on your RTA and hear with your ears when phase is causing cancellation instead of increased amplitude. Try this simple experiment. Put two subs side by side. Make the phase 180 degrees. You won't even be able to hear the subs anymore. Move the subs apart, and viola! you start hearing them. The same is true if you have two subs apart a certain distance and have the phase set at 0 degrees. Your room modes at certain frequencies and in certain positions will be dependent on the frequency and distances the sound waves travel and collide. That is why it is crucial to adjust the phase on subs that are not adjacent or stacked. Adjusting the phase lets the subs work together to minimize room modes. I just found this graphic that shows how sound waves behave: Here is an example of what adjusting room modes can look like. Too much red and blue are bad in this graphic: Quote Link to comment Share on other sites More sharing options...
Ski Bum Posted March 9, 2014 Share Posted March 9, 2014 Can you look at the measurement and see if the phase is out? If so can you show me how it's done? That's an informative post by Mustang Guy. If the phase is not correct, you will get cancellation at the crossover frequency causing a narrow, deep dip. Now keep in mind that this is evident with symmetrical slopes. I'm not sure what you get when you have a steep slope on your sub and a shallower slope on your mains, or vice versa, but I suspect it will be more like the third example in the first graphic that MG posted. The more closely the actual acoustic output of your speakers and subs are to textbook examples, the better the results will generally be, or rather the easier it becomes to get good results. That's been my experience, at least. Think of the THX standard, for example, which is essentially where your recently tweaked settings have you. I think THX is something like -3db crossover point at 80 hz, 24db/oct slopes both sides, phase 0 deg (or close to it, depending on sub placement r/t mains and listening position). It sums flat when in phase, but has a narrow, deep cancellation when out of phase. Another example, I have one system where the mains roll off at 12db/oct (sealed, no upstream hp filter), the sub's lp is also 12db/oct, the crossover freq is set so it's ~-6db, sub phase -180 or thereabouts; it sums flat when in phase, deep dip at the crossover freq if not. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 9, 2014 Author Share Posted March 9, 2014 We may be on to something here then, my subs are directly across from each other about 11 feet apart with the phase set to 0... I did some listening last night and it sounds pretty good but, maybe a bit too much bass. So I turned both subs down a little and will listen again. Quote Link to comment Share on other sites More sharing options...
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