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davidpa Unregistered guest | posted here couple days ago about my nht 2.9s. Decided I really liked the aerial acoustics so I Went with aerial acoustics 9s, cc3 center, and also picked up bryston 14B for lf rf. In the mean time I got my paradigm servo 15 back from service, and put it back in system today, Now I have a serious problem, and was hoping someone here could help. Since hooking up servo 15, I have lost bass response in room, and it doesnt even sound like the servo is integrated in system, unless your in another room, or in the basement where its shaking everything. Ive tried a couple different locations to no avail, and am wondering what the problem could be, Also since I have not yet recieved my aerials, the bottom half of the NHTs produce most of the bass for the system, or at least thats what can be heard when gain is adjusted. Any ideas or helpful hints would be greatly appreciated. If there is info Ive forgotten to submit for your info let me know and I will respond asap. I did adjust phase to 0 for the bottom half of NHTs and that seemed to help, but did nothing for servo, or NHT 12" that is also in system. Thanks in advance. Dave |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 6625 Registered: May-04 | What you describe is typically the result of standing waves. Can you give some information concerning how you determined placement of the sub and your listening position? Did you use any information or internet sites to calculate what the room nodes will be? And, is there no bass at any location in the room or just at your listening position? |
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davidpa Unregistered guest | thanks jan. I placed the sub in its location now, after moving sub around room, walking around and finding "hot spots" for best sound, I also placed it where I typically sit and walked around to see if placement in these hot spot areas would be good at listening position. This was done well before it had to go into shop, so I put it back where in the same spot I took it out of. I did not use any internet sites for calculation. And finally there is much more bass when I turn off the 12" NHT sub.hope that helps. What if anything can I do about the standing waves? Or is this just a matter of placing each sub in totally different locations?(which they are now) And if so, how can I do tests with both subs, if the best sound comes from the same spot? Thanks in advance |
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New member Username: 2morexExmore, Virginia USA Post Number: 1 Registered: Nov-05 | David: I read somewhere that you can place the sub in your listening position and them physically move around the room to where the sub sounds best. If you find that spot, then place the sub there. I have never tried it but some people believe it works. |
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davidpa Unregistered guest | robert, I have tried that. The problem is that when both NHT 12" sub and paradigm are on, Bass dissappears. And when compared output, depth, fullness, and response the NHT is making the paradigm sound like a 4" midrange. And the only bass that Im hearing when both are on IS the NHT. Except in another room or in basement, where the paradigm seems to want me to be. |
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Silver Member Username: NuckParkhill, Ontario Canada Post Number: 388 Registered: Dec-04 | davidpa, have you tried placing the paradigm in the other room or basement? What effect do/would you get when you try that? Harmonic symbosis is something I've just started reading, but primary(sub) signals can cancel each othr out, much the same as white noise can be used to dampen frequencies in an automotive arrangement. Can you phase shift either sub, or try, if you like, reversing the polarity of the paradigm for a test? |
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Gold Member Username: T_bomb25Dayton, Ohio United States Post Number: 1260 Registered: Jun-05 | David its only so bass a room can support,your subs are cancelling each other out,and it also seems your have a very bad case of 100 to 50 htz suckout,thats dropping output by a least 5dbs.David bass is fun,but sometime you can have to much for a given space.Try your speakers on their own and then try both subs with your speakers,first with your NHT subs and then with your Servo-15,your room seems to be small for all these bass waves,your just gonna have to go for the best intergrated bass you can find.Which meaning your probably gonna have to retire one of the subs to another room. |
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Silver Member Username: NuckParkhill, Ontario Canada Post Number: 393 Registered: Dec-04 | Is there an echo? David, move the big sub to the other room(or basebent) to cancel out the cancel out, so to speak. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 6628 Registered: May-04 | Bass problems are quite difficult to diagnose and cure since what I consider good bass response might be lacking considerable depth and energy to someone else. None the less, the problem would appear to be three fold. First, there are more than liklely standing waves being set up in the room. Every room has them to some extent just as every room has nodes which emphasize the response in narrow frequency bands. However, standing waves and nodes are limited in their location within the room. If you move several feet either side of the null, there is bass once again. As you walk through the room, you will hear the rising and falling response of room problems. If I understand your post, there is no bass response in your room at any listening position. This would then indicate we are looking beyond room problems. Second, the two subs would appear to be out of phase with each other. I suspect phase problems at this point, but require some clarification from you. Finally, you would appear not to have a logical approach to solving the problem. That's not a slam; just an observation. The way to solve the problem is to methodically remove the variables until only the problem and (hopefully) the solution remain. Let's get a few things straight and then we can possibly go from there. First, you need to read a few articles so you can make some assumptions as you work through the problem. Here are a few to begin with: http://www.harman.com/wp/index.jsp?articleId=131.0 http://www.harman.com/wp/index.jsp?articleId=1003.0 http://sound.westhost.com/subcon.htm http://www.audioc.com/library1/subprimer.htm http://www.sonicdesign.se/subplace.html Some of the information in the articles might seem contradictory to one another. That merely indicates there is more than one approach to getting good sound in your room. Glean what you can from the combined articles and go from there with some amount of knowledge. I'm going to give you the situation as I see it and you tell me if I'm right or wrong. 1) You got the Servo back from service and put it in the same location where it had sat before. Yes? No? 2) Before the service, the Servo had performed adequately in the system. Yes? No? 3) Before the service it was also combined with the NHT speakers and NHT sub. Yes? No? 4) This combination of speakers and two subs in identical locations had worked fine before the Servo went in for service. Yes? No? Now that the Servo is back from service, there is a problem. The Servo appears to be working since you can tell there is output from the sub when you are in another location. 5) The problem occurs when the Servo is in the system playing with the NHT sub. Yes? No? 6) When the NHT sub is eliminated from the system, the problem is not as great. (Does that mean the system sounds OK without the NHT? Just less bass than before the Servo went in for service? Or, is there still a problem even though the NHT is out of the system?) 7) The Bryston amp is the only new addition to the system. Yes? No? 8) No new cables or interconnects were added along with the amp. Yes? No? 9) The Bryston was added at the same time the Servo was put back in the system. Yes? No? If all of the above are "Yes", the first thing I would do is eliminate everything from the system except the main speakers. Check the wiring of the speakers carefully both at the speakers and at the amplifier. I suspect there might be an out of phase connection somewhere in the system. Tell me what the response is with just the main speakers connected. OK? Not good? If the wiring is correct to the Bryston amp and all the speakers, add the Servo sub only. I assume you are running the sub from a LFE output. Is that correct? Tell me what the response is with just the main speakers and the Servo connected. Good bass response through out the room? Disconnect the Servo and add only the NHT sub. Tell me what the response in the room is. If everything was the same before the Servo came back from service and the Bryston amp was added, the problem is likely to be in the wiring to one of those two components. It is quite possible the service tech wired the Servo in reverse phase. I'm only guessing since I'm making lots of assumptions here. |
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davidpa Unregistered guest | Thanks for all of your input. Ill start by saying that when each sub is playing on its own there is bass in the room, just more so when bottom of NHTs are on, and or with the 12 NHT. The bottom half of the NHTs seem to give the best bass, when I add the NHT 12" bass is fuller, and deeper, Its really when I power up the paradigm that I lose bass response. I did check to see if there were any reversed wires on paradigm and cannot see that that has happened, but I do notice a significant change in bottom half of NHTs when phase is set to 0, as opposed to 180, when other subs powered up. The paradigm did work with system before repair, but now that it actually is "working correctly" Im wondering if it really wasnt? As far as bass response goes, there is definitely areas in room where its almost as if it has disappeared, but boomy in other areas. I have tried locating sub in different parts of room, and also at different angles to see what happens, and the result is the bass signature is also moved to another location. To answer Jans questions here we go. 1) Yes 2)yes and no, since it was making static noises when not even on, and popping sounds like it was blown, I really dont know if it ever was working correctly from the time I bought it? 3)yes 4) yes, and actually I had to turn down bottom half of NHTs, and 12"NHT because of too much bass, BUT-the paradigm did fit into system, it just never seemed to be as rich, and filling, or as loud as when I demod it. 5)Yes the problem is much more noticable when the 12" NHT is also powered up, but it doesnt seem to affect the NHT, IF I turn up volume on its amp. 6)there is still a problem when NHT is out of system, the paradigm does not sound like its even integrated in the whole of the soundstage, either too much or none. 7)The bryston amp is the only new piece right now, and it is only powering the top half of NHTs. 8) No new cables, and 9)bryton was put in before I got the paradigm back. Now for the rest of what you needed, When just the NHTs are playing by themselves, and bottoms are powered by external ams, they sound great, full,snappy, rich extended bass. Both the NHT and paradigm subs are connected to LFE outs. When disconnected the NHT, I get same result in paradigm, too much bass, or no bass, or even right at the rack it sounds like an AM radio broadcast. With just NHT bass sounds pretty good, The only thing I can think is to put the paradigm where the NHT is and try that as well. I hope I have added enough info for you pros, I need the help. It would be so disappointing to get my aerials here and then not be able to get full sound out of whole system, I really appreciate all of your input, as it has me trying things I would have never thought of on my own. hope this is an easy fix, thanks in advance, Dave |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 6635 Registered: May-04 | "When disconnected the NHT, I get same result in paradigm, too much bass, or no bass, or even right at the rack it sounds like an AM radio broadcast." That would indicate room problems. We need to determine if the Servo is operating properly before we tackle those. Have you read any of the articles? You will generally do better with two subs when they are not on the same or parallel walls. "I did check to see if there were any reversed wires on paradigm and cannot see that that has happened, but I do notice a significant change in bottom half of NHTs when phase is set to 0, as opposed to 180 ... " This still leads me to believe the phase has been reversed on the Servo. I assume it has no provision for phase adjustment. Just what are you able to check on the Servo? Can you see the connections to the amplifier outputs and the driver inputs? That is the most likely spot for the problem to occur during reassembly. Possibly describing the room and system set up. most particularly the sub woofer placement in relation to the main speakers, might be of benefit. Have you, by chance, tried this set up? No NHT sub. Place the Servo in the same location with the NHT mains. BTW, you might want to begin taking some notes regarding your trials in case this has to go back to the repair shop. |
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davidpa Unregistered guest | Jan, THANK YOU!! I read the articles, and yes there was some conflicting info, but I used everything available, and with some time I have found the bass! Both the paradigm, and NHT are performing above my expectations, AND the paradigme sounds like it did when I demod it! gains on both subs are set to lowest setting EVER! Now I have bass where its supposed to be....EVERYWHERE! Now if my aerial acoustics would just come in! I cant thank you enough for the info, my problem was working with only one sub at a time, had a good location for NHT alone, and paradigme OK for listening position, but now that they work together all I can say is WOW, now its starting to sound as good as the investment! I cant thank you enough, you have eased my disappointments and helped me through a difficult situation, once again but not enough THANKS Dave |
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Silver Member Username: NuckParkhill, Ontario Canada Post Number: 432 Registered: Dec-04 | Davidpa, any chance of showing a layout, or a few pics of the solution? I've been following, trying to envision your work(and trying to keep up with Jan's thinking). I would be rather interested to see the solution and the room. Jamie |
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davidpa Unregistered guest | Ill try to get pics, will have to get my sons assistance. Im sure after you see pics all you audiophiles will surely think Im an absolute moron, which Im starting to think myself! Solution was simple if you know what to do. And I didnt. |
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davidpa Unregistered guest | tried to upload to here, but apparently file size is too big, Jamie-I emailed pics to your email address, hopefully that even worked, Im trying this without my computer wiz son. let me know if it worked. Dave |
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Silver Member Username: NuckParkhill, Ontario Canada Post Number: 439 Registered: Dec-04 | Got em David. Forest for the trees? Nice layout, I can see where the crosstalk could be hard, specially with return in the sub. Looks very good, thanks for the mail, hope you stick around! Jamie. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 6647 Registered: May-04 | "trying to keep up with Jan's thinking." Geez, even I can't do that most of the time. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 6648 Registered: May-04 | BTW, glad to hear the articles helped. |
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davidpa Unregistered guest | thanks, color scheme all my wifes! Shes actually really good about all this. Im not going anywhere, info that I get from here is invaluable. Its just nice to have an investment pay off! Just about done, now just waiting for aerials, then Ill look into a couple more brystons for rest of surround. funny thing is, while all this is going on, my projectors color wheel took a s**t, so I wont have that back until tomorrow-but it is the same day the speakers are supposed to be here. So WATCH OUT NEIGHBORS! ITS MOVIE TIME! |
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Silver Member Username: NuckParkhill, Ontario Canada Post Number: 442 Registered: Dec-04 | davidpa, did you cc Jan with the pics? I figgured you did. |
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davidpa Unregistered guest | no, I didnt want to impose. You asked so I sent them to you. If Jan wants to see I would be more than happy to send to her also. Itd be so much easier if I could find a way to post here, but... |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 6649 Registered: May-04 | Thanks, but since I have decided I'm not interested in the number and probable type of emails I would receive should I post my address, I'll just have to take your word on this one. Possibly your son can get them posted on the forum. |
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Silver Member Username: NuckParkhill, Ontario Canada Post Number: 443 Registered: Dec-04 | Jan, a classic Vigne fix. Kudos for you and Davidpa, stick around! |