iTide Posted March 30, 2009 Share Posted March 30, 2009 Okay, I picked up a used RC 25 and I am loving it. I can't get over how good it sounds. I do not have it hooked up as a center yet. I hooked it up as the right speaker in my stereo setup upstairs. It sounds fantastic with every song I play, until it hits pretty hard. Just for fun I put in Flo Rida's "Low". When the bass hits, I hear a rattle in the left port. I don't hear anything in the right port. I was playing it pretty loud, but should it be making this noise on only one side? What do you all think. Thanks Quote Link to comment Share on other sites More sharing options...
sean5340 Posted March 30, 2009 Share Posted March 30, 2009 It could be a wire touching the port tube. I'm not familiar with that speaker but if there is enough slack in the wire it could happen. Sean Quote Link to comment Share on other sites More sharing options...
slumberer Posted March 31, 2009 Share Posted March 31, 2009 Several center channel speakers of the MTM design have a varied bass distribution between the two mid drivers. When you get it positioned as your center, try adjusting the crossover for it and see if you can get rid of the rattle. The noise from the one side might stem from lower bass frequencies being sent to that driver rather than a physical problem. Quote Link to comment Share on other sites More sharing options...
tommyboy Posted March 31, 2009 Share Posted March 31, 2009 It could be because it's a center speaker, and it's not supposed to receive such bass loads. I'm sure the issue will go away when you hook it up to the center channel............. Quote Link to comment Share on other sites More sharing options...
iTide Posted March 31, 2009 Author Share Posted March 31, 2009 Well that is what I was hoping. The center really does sound perfect at normal listening levels. I was just giving it a good workout since I just bought it used and I was trying to listen for any problems that I could find. When I was hearing the noise I was playing it loud and the bass was hitting really hard. I just couldn't figure out why it was making the noise on one size. I went back and listened again and I could hear it a little on the other side but just not as much. You have to listen pretty closely to even hear it. So, I am new to this whole HT thing. I have a few more question after reading your responses. 1. When I set up the HT will I also set the crossover point for the center speaker. It is rated down to like 60Hz I think? 2. If a speaker is rated at 60 Hz will it not play anything lower than that or will it play it but only distorted? I know these are probably dumb questions, but I have got to learn somewhere. Thanks Quote Link to comment Share on other sites More sharing options...
slumberer Posted March 31, 2009 Share Posted March 31, 2009 Welcome to the wacky quest for optimum home theater performance! 1. How you set your crossover depends on your receiver and sub, most modern home theater receivers will allow individual crossover adjustments. 2. Rated frequency response for speakers is generally measured in controlled environments where the manufacturer tries to get a baseline performance of the speaker without room interactions factored in, depending on your room and placement you might get more or less extension, but loud passages at lower than the rated frequency should not be sent to the speaker. In my room and placement, my center channel (Heresy III) does not get close to the rated low frequency extension. I cross it over at 90hz. The widely accepted idea is that bass frequencies below 80hz cannot be localized; meaning you can't tell where they're coming from. So this is the default crossover for many applications and most home theater speakers will reproduce 80hz. If you select THX settings in any portion of the signal from the source to your speakers, the signal will automatically be crossed over at 80hz at that point in the line. I get away with 90hz because my sub is in front, right next to the center channel, and I never use THX listening modes. There are two philosophies about frequency response for home theater, one is to get the absolute maximum output for each speaker by using placement and room treatments to 'tune' the room for accurate reproduction. If you have less flexibility for placement as in a living room system, the other road is to get a good placement scheme and then work within your room response by adjusting crossovers and the equalizer settings in your receiver to get the most accurate sound possible with your setup. A compromise between the two is what most people end up with. To get decent integration of your speakers and a subwoofer, you will need a test disk such as Avia and a sound pressure meter unless you have a receiver will auto room correction. Using the disk to run low frequency sweeps and watching the meter, you can see at what frequency your speakers start to drop away in sound pressure level (SPL). The rule is that +- 3db or more on the meter will be noticeable when listening. If your speaker starts dropping off at 72hz, you might try to move it around a few inches left, right, front, back. If you cannot get 70hz, then set your crossover for that channel at 80hz. You may need to overlap the crossover between the speaker with the highest crossover frequency and the low-pass setting in your subwoofer (like 80hz in the speaker and 100hz in the sub) to get a smooth integration because electronic crossovers are usually very steep. Some people prefer to simply defeat the low-pass in their subwoofers or set it to the highest value (usually 120 or 140hz). Receivers are getting very powerful nowadays and some will run auto calibrations using microphones to do the crossover adjustments and also assign equalization to each channel giving very flat response, although you will still need to manually fiddle with the subwoofer unless you get one with room correction circuitry built in. Graphic and parametric equalization can be used to flatten response manually if you have some older gear or you just want to be hands-on, but these techniques can wait until you get the system going and feel like playing with it some more. By the way, if you don't want to mess with it, the THX recommended 80hz crossover will probably sound pretty good for most situations. LOL! Any other questions, feel free to ask. Quote Link to comment Share on other sites More sharing options...
tommyboy Posted April 1, 2009 Share Posted April 1, 2009 Well, I think Slumberer pretty much has you covered! Let us know if the issue goes away after you get it hooked up as a center............ Quote Link to comment Share on other sites More sharing options...
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