liebherr954 Posted May 7, 2010 Share Posted May 7, 2010 I have a couple a questions reguarding the UPA-2 amplifier.I was thinking about picking up the UPA-2 to ease the strain on my receiver and I was looking at the specs and it the THD levels are 125 watts RMS@8oms (0.1thd) is that high for a dedicated amp? I'm going to be using it to power my RB-81s. I mostly want to get an amp so I can switch off my sub 12 when I listen to music because I find it to boomy. Is there anyone with this amp who can give me some feedback about it.Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted May 7, 2010 Moderators Share Posted May 7, 2010 If your sub is too boomy, I would try moving it away from the wall some. Even with RF-83's, I still prefer to have my sub turned on for 2ch. If you add an amp, you will likely get more bass from the RF-81's but I can't see them providing enough bass to allow you to feel the music. Just my 2 cents. Not sure about the .1 total harmonic distortion. Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted May 7, 2010 Moderators Share Posted May 7, 2010 I just looked at the specs for my amp. Total Harmonic Distortion < 0.03 % at full power; < 0.01 % typical levels .03 vs .1 percent seems like a big difference but I'm not sure how much our ears can actually hear or if that is just "measurable" numbers. Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted May 7, 2010 Moderators Share Posted May 7, 2010 For what it's worth, I found this online: Why is it Important? In reality, total harmonic distortion is hardly perceptible to the human ear. Every component adds some level of distortion, but most distortion is insignificant and small differences in specifications between components mean nothing. Some components have distortion so low it cannot be accurately measured. Listening to a component and evaluating its sound characteristics is the most important way to judge a product. Other considerations, such as room acoustics and selecting the right speakers are more important than the percentage of total harmonic distortion. Wikipedia suggests that anything less than 1 % is inaudible. Link Hope that helps. Michael Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted May 7, 2010 Moderators Share Posted May 7, 2010 For what it's worth, I found this online: Why is it Important? In reality, total harmonic distortion is hardly perceptible to the human ear. Every component adds some level of distortion, but most distortion is insignificant and small differences in specifications between components mean nothing. Some components have distortion so low it cannot be accurately measured. Listening to a component and evaluating its sound characteristics is the most important way to judge a product. Other considerations, such as room acoustics and selecting the right speakers are more important than the percentage of total harmonic distortion. Wikipedia suggests that anything less than 1 % is inaudible. Link Hope that helps. Michael You are just on the ball lately ! [Y][H] Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted May 7, 2010 Moderators Share Posted May 7, 2010 You are just on the ball lately ! Only lately? I must be losing my game. LOL Quote Link to comment Share on other sites More sharing options...
RockOn4Klipsch Posted May 7, 2010 Share Posted May 7, 2010 when I saw the question I was going to post about ours ears preception but Youthman has got it all taken care of. Any info on my question in the Tech Section on vintage equipment? hahaha Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted May 7, 2010 Moderators Share Posted May 7, 2010 Any info on my question in the Tech Section on vintage equipment? hahaha Nope, don't think I've ever visited the tech section. I stay in the HT and Garage Sale only. [] Quote Link to comment Share on other sites More sharing options...
wuzzzer Posted May 7, 2010 Share Posted May 7, 2010 Having my front Fortes powered by a UPA-2 made a noticeable difference. The biggest difference was more clarity and bass at higher volumes but even at medium listening levels I could hear an audible difference. While it can be beneficial to have an outboard sub, setting up a sub properly is very important too. It shouldn't ever sound boomy. Either your crossover level is set too high, your output level is set too high, the sub isn't in the ideal location in your room, or a combination of the 3. Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted May 8, 2010 Moderators Share Posted May 8, 2010 You are just on the ball lately ! Only lately? I must be losing my game. LOL Nope just faster lately.[] Quote Link to comment Share on other sites More sharing options...
liebherr954 Posted May 8, 2010 Author Share Posted May 8, 2010 thanks for the help wuzzer, the gain is at the 8 0'clock position and the cross over is set at 90, maybe ill set it to 80Hrz. The sub sounds great for movies but I've noticed with certain types of music, mostly instrumental it sounds boomy. I guess ill try playing with the settings and placement.Thanks again Quote Link to comment Share on other sites More sharing options...
liebherr954 Posted May 8, 2010 Author Share Posted May 8, 2010 Thanks for the article and info Youthman. I will try moving my sub today and see if that helps at all. Maybe I should think about replacing my aging receiver first, some of the new Yamaha receivers are getting great reviews. Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted May 8, 2010 Moderators Share Posted May 8, 2010 +1 for the Yamaha. Love mine. Two thoughts on the sub: 1. If possible, place your sub in the seat of your primary listening position. Then play something and crawl around on the floor until you hear the smoothest bass response. That is where your sub should go. It's basically reverse acoustics. 2. I was once told that you should only notice your sub if you turn it off. You really want it to blend well with the rest of your speakers and never draw attention to itself. When I'm watching movies or listening in 2ch, you hear the bass but you cannot tell where my sub is located. Sometimes I wonder if it's even playing and am tempted to turn the gain up but then once I turn the sub off, I immediately can hear the loss of bass. That's what you want to shoot for. Quote Link to comment Share on other sites More sharing options...
liebherr954 Posted May 8, 2010 Author Share Posted May 8, 2010 thanks guys for the help. I moved the sub another foot away from the wall turned the cross over to 80Hrz and turned the gain down 1 notch and it sounds way better. I can't believe there is so much to setting up a sub?! Quote Link to comment Share on other sites More sharing options...
Stolenrs Posted May 8, 2010 Share Posted May 8, 2010 2. I was once told that you should only notice your sub if you turn it off. You really want it to blend well with the rest of your speakers and never draw attention to itself. When I'm watching movies or listening in 2ch, you hear the bass but you cannot tell where my sub is located. Sometimes I wonder if it's even playing and am tempted to turn the gain up but then once I turn the sub off, I immediately can hear the loss of bass. That's what you want to shoot for. I really agree with this, it took me several attemps to find the right placement for my subs, I have a big bay window built out in my room so it really throws off the acoustics of the room. I did the same as youthman says I put one of them in my chair turned it to listening volume and walked around the room untill I found a dead spot, placed the sub there and then again for the seconed sub. Now when listening to movies or music there is really no way you can tell where the bass is comming from, also I noticed that as I played my subs more that there was a difference in sound and had to adjust my amp settings a couple of times. ~ross Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted May 8, 2010 Moderators Share Posted May 8, 2010 I must confess that I have not even dont the "crawl" with my setup. That is just what others have suggested. I only have two locations I can place my sub and it is in one of those locations behind the false wall. I put one of them in my chair turned it to listening volume and walked around the room untill I found a dead spot, placed the sub there and then again for the seconed sub. It was my understanding that you don't look for dead spots (nulls) but you look for smooth sounding bass? Maybe I'm wrong. Can others clarify? Quote Link to comment Share on other sites More sharing options...
synergyfreak Posted May 8, 2010 Share Posted May 8, 2010 I had to do the same thing with sub-12 have the gain at half way, and low pass crossover set at 80 hertz made a huge difference. Took the boominess out of my sub. Quote Link to comment Share on other sites More sharing options...
wuzzzer Posted May 8, 2010 Share Posted May 8, 2010 thanks guys for the help. I moved the sub another foot away from the wall turned the cross over to 80Hrz and turned the gain down 1 notch and it sounds way better. I can't believe there is so much to setting up a sub?! A mid-range sub properly set up will sound and perform much better than a massive sub not set up correctly. Its worth it to spend the time to make it the best you can for your room. Quote Link to comment Share on other sites More sharing options...
Stolenrs Posted May 8, 2010 Share Posted May 8, 2010 I must confess that I have not even dont the "crawl" with my setup. That is just what others have suggested. I only have two locations I can place my sub and it is in one of those locations behind the false wall. I put one of them in my chair turned it to listening volume and walked around the room untill I found a dead spot, placed the sub there and then again for the seconed sub. It was my understanding that you don't look for dead spots (nulls) but you look for smooth sounding bass? Maybe I'm wrong. Can others clarify? I was told to look for a dead spot so that it fills in, maybe the difference is because I am running two subs vs. one. I spent alot of time with my LRD (major klipsch dealer) as well as time on the phone with Rockford tech support to get the boxes just right. The one thing I was told not to do was place the subs facing each other as it will produce a cancelation effect. I don't know if they knew what they were telling me, but they have a pretty awsome room setup with dual subs, and I really enjoy the sound that mine produce, room filling, multi-dimensional bass. but then again I could have just been very lucky in the placement or the subs produce so much bass I can't tell if they should be moved or not......hmmm ~ross Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted May 8, 2010 Moderators Share Posted May 8, 2010 I'm not sure. I would be curious to see what others say about this. I too have heard that two subs can sometimes cancel out each other. Guess it depends on when and how the sound waves hit each other. I have some seats in my room that have less bass than others. I'm hoping one day to add another HGS15 to the other side of the false wall in hopes that it would help even out the bass response throughout the room. Quote Link to comment Share on other sites More sharing options...
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