D-MAN Posted March 9, 2006 Share Posted March 9, 2006 Now that you guys with Bob's new tweeters have increased your high frequency response, got a question for you... I've noticed that some of my most cherished CDs, specifically, classical recordings on violin sections especially, tend to have a high frequency "microphonic/SS" sound to them that is irritating me. It is a definite electronic signature that I think is probably what some refer to as a SS signature very high frequency "buzz" or "tizz". Have you noticed this? It will be there but it is very high in frequency. I would say its almost like a hum, but we tend to think of hum as being rather low in frequency. It's not quite what I would call a hiss, it is specific to violin sections so it tends to come and go depending on the particular piece, and it appears to cross recording companies. I find it on Telarc (especially) and DG (but I haven't gone through all of the DG recordings that I have yet), but not Sony. Again, its actually on the recordings, it's not an equipment issue. Do you have the same experience? Anyway, when you run across it, you'll know. DM Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 9, 2006 Share Posted March 9, 2006 I've noticed something seriously annoying with FM with the new tweeters. I have a good number of fringe stations that I like to listen too that I can no longer enjoy. The background noise on these stations is a high frequency hiss that has audibly increased. I just noticed this today. It was present before but at a lessor more tolerable degree. It really comes forward between songs when commercials or the DJ is talking. I enjoy listening to FM while I'm soldering but I'm only about 4 feet from each speaker with them both being on the ends of a 8" work bench. The entire problem with improvements is you may gain in one area but create problems in another. Craig Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted March 9, 2006 Share Posted March 9, 2006 DM Haven't noticed this. Quote Link to comment Share on other sites More sharing options...
gonzp Posted March 9, 2006 Share Posted March 9, 2006 Quite typical of high efficiency horn speakers, they are always right on the edge of being harsh. I have noticed with the new tweeters that recordings definately come into play. Nothing sounds better than a great recording and nothing sounds as bad as a bad recording. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted March 9, 2006 Share Posted March 9, 2006 What this sounds like is improved HFR with Bob's tweeter. Where certain high frequencies with the stock drivers may have rolled off some of this unpleasant oscillation-like distortion with distant stations, the new tweeter reproduces with greater clarity. I'm just talking about this in an objective sense. They might be more revealing of certain characteristics of associated electronics. For example, if there was some instablility or oscillation associated with the receiver, preamp, or amplifier that wasn't audible before, the more extended FR of the BEC drivers might be bringing them to the forefront with significantly greater strength. IOWs, the commonly mentioned fact that the big Klipsch Heritage horns require clean electronics in front of them might be even more true with Bob's tweeters. Grid stopper resistors are obviously one possible cure, and I don't know if the VRDs or preamp use them in voltage gain or output stages. But you might give that a try just to see if it helps, and experiment with different values until it improves. The problem is that, just as you said, there may be an improvement in one way that is derived by a compromise in another. For example: You might find that it takes 15k ohms in series with the grid to quiet things down, but on the other hand discover that you've lost some 'life' and 'sparkle' it had before. I guess one might have to consider what one would rather have -- an improvement in overall audio clarity and frequency response for digital or analog playback, or the now irritating edge that was suddenly honed on the blade of distant or weak radio stations. What provides the bulk of one's listening enjoyment might help make the decision easier. Erik Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted March 9, 2006 Share Posted March 9, 2006 ...or, more simply: install an variable L-pad inline with the tweeter to reduce it's output a bit. Erik Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted March 9, 2006 Share Posted March 9, 2006 ...or, more simply: install an variable L-pad inline with the tweeter to reduce it's output a bit. Erik Erik, I think that you are saying "trash in-trash out" just in a different way. Or perhaps an active type system with an L-pad???? tc Quote Link to comment Share on other sites More sharing options...
LarryC Posted March 9, 2006 Share Posted March 9, 2006 DM, I haven't heard that either, and I think I would have noticed it. I happen to believe that solo strings are more difficult than any other instrument or voice for digital to reproduce accurately. However, this sounds like an artifact. Are you sure it's not something in your playback equipment? Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 9, 2006 Share Posted March 9, 2006 What this sounds like is improved HFR with Bob's tweeter. Where certain high frequencies with the stock drivers may have rolled off some of this unpleasant oscillation-like distortion with distant stations, the new tweeter reproduces with greater clarity. I'm just talking about this in an objective sense. They might be more revealing of certain characteristics of associated electronics. For example, if there was some instablility or oscillation associated with the receiver, preamp, or amplifier that wasn't audible before, the more extended FR of the BEC drivers might be bringing them to the forefront with significantly greater strength. IOWs, the commonly mentioned fact that the big Klipsch Heritage horns require clean electronics in front of them might be even more true with Bob's tweeters. Grid stopper resistors are obviously one possible cure, and I don't know if the VRDs or preamp use them in voltage gain or output stages. But you might give that a try just to see if it helps, and experiment with different values until it improves. The problem is that, just as you said, there may be an improvement in one way that is derived by a compromise in another. For example: You might find that it takes 15k ohms in series with the grid to quiet things down, but on the other hand discover that you've lost some 'life' and 'sparkle' it had before. I guess one might have to consider what one would rather have -- an improvement in overall audio clarity and frequency response for digital or analog playback, or the now irritating edge that was suddenly honed on the blade of distant or weak radio stations. What provides the bulk of one's listening enjoyment might help make the decision easier. Erik Erik, I swear you sure can be clueless. You think I should modify my amps or preamps to makeup for noise from fringe FM stations!!! Un freaken believable. Wouldn't the smart thing do do is fix the problem at its source which is the weak stations??? Maybe a better roof mounted attenna and/or better Tuner that can pull in these fringe stations. You won't find me installing 15K grid resistor in any amplifier! I have no problem that BEC's tweeter causing me to hear more pronouced HF noise in these stations it's the price you pay for improvements. It just means I have to remedy the problem at the source which is not his tweeter or my grid stoppers. Talk about a bandaid job. Craig Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted March 10, 2006 Share Posted March 10, 2006 Craig: Sure, you are entitled to think what you wish -- I was actually trying to help you with this. Antennas are the single most important component for any receiving-based system, and that is pretty obvious. However, the symptoms or problems we sometimes try to explain with words can often be hard for others to interpret. I wasn't sure if your problems were due to weak reception or something else, and was simply mentioning a cure I had found helpful in the past. As far as I know, there wasn't any name-calling in the post I had written. So, Yes, the 'smart thing' or solution to this problem might be a better antenna; however if that were so obviously the correct thing to do, you didn't even mention it in the post that described this problem. That said, you are probably right. Depending on the load impedance of the circuit in question, a 15k ohm resistor might not be so wild an idea. I have components here (not my design) that use 10k ohm in series with grids, and the response seems completely unchanged. Grid stopper resistors have a very long history behind them, Craig, and they are very commonly used. In the last sentence of your response, you-yourself describe the use of 'my grid stoppers.' Are those in the first or output stage (or maybe both) of the amps, and are they used in those positions as bandaids? All I was trying to do was offer a suggestion for something that might help. I wouldn't tell just anyone to go and throw in some series resistance to help calm possibly hyper-active grid circuits. You have the technical ability to do the work, which wouldn't take more than a few minutes, so I thought I would mention it. Erik Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted March 10, 2006 Share Posted March 10, 2006 Terry: "Or perhaps an active type system with an L-pad????" I was talking about the use of an variable L-pad on the tweeter to lower its output a bit. Basically the same thing as volume control dedicated to a specific driver. For my part, I would rather use a tweeter that had the ability to reproduce such unwanted noise. It pointed to a weaker link in the system, and so the way I would solve the problem would be to address that weaker link rather than use a less revealing driver. In the end, some might just prefer the K-77 overall, which is great. I am thrilled to be getting a pair of Bob's new tweeters, along with a pair of his networks. Daddy Dee, as nice as he always is, has sent me this equipment to audition with our Klipschorns over my spring break next week -- and to use them for awhile after that. Very, very kind, and I am looking forward to it! Erik Quote Link to comment Share on other sites More sharing options...
leok Posted March 10, 2006 Share Posted March 10, 2006 D-MAN, I've been working on cleaning up violin reproduction for years. I've found numerous sources of distortion and resonance that contribute. The grid-stopper that Erik mentioned is one of about 10 (maybe more) contributors. I just found them, one by one and fixed them. If you want I could make a list of all the possibilities I know of and send them, or post if people are interested. Now I can listen to string quartets, piano quintets, trios, etc. and hear the music and expression without the distraction of little electromechanical oscillations and gratings. I suspect, in the end, even with the best of equipment, some final work is required to remove various application-specific interactions between the components. Leo Quote Link to comment Share on other sites More sharing options...
Jeff Matthews Posted March 10, 2006 Share Posted March 10, 2006 I can never enjoy the radio through my system - at least not when I want to hear something that sounds good. It's been that way with Corns and KHorns. I just figured that FM quality sucks in Houston. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 10, 2006 Share Posted March 10, 2006 Guys, I think a lot of this is just noticing stuff that has always been there! When you make a change in your system it's normal to listen more closely. This make you hear things that were always there but you just didn't notice before! Bobs new tweeter goes up higher than the K77, but the extension is really beyond most peoples hearing. I can't hear beyond about 14KHz. Virtually any K77 will go to 14K! FM stations are often very poor quality. In this area there is only a single station that has good quality. That's the PBS classical station WSCL. All the rest are compressed and clipped form maximum "punch". I have a scope connected to my FM tuner and I can not only hear it but I can also "see" it! AL K. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted March 10, 2006 Share Posted March 10, 2006 D-MAN, I've been working on cleaning up violin reproduction for years. I've found numerous sources of distortion and resonance that contribute. The grid-stopper that Erik mentioned is one of about 10 (maybe more) contributors. I just found them, one by one and fixed them. If you want I could make a list of all the possibilities I know of and send them, or post if people are interested. Now I can listen to string quartets, piano quintets, trios, etc. and hear the music and expression without the distraction of little electromechanical oscillations and gratings. I suspect, in the end, even with the best of equipment, some final work is required to remove various application-specific interactions between the components. Leo Leo, I hope you can get this list together. It is worthy of starting a new thread, I think. I know of at least one forum member in Little Rock who has mentioned stridency in strings being a frustration in listening. Quote Link to comment Share on other sites More sharing options...
leok Posted March 10, 2006 Share Posted March 10, 2006 I'll go ahead an post the list. It will take me a day or two. Leo Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 10, 2006 Share Posted March 10, 2006 Guys, I think a lot of this is just noticing stuff that has always been there! When you make a change in your system it's normal to listen more closely. This make you hear things that were always there but you just didn't notice before! Bobs new tweeter goes up higher than the K77, but the extension is really beyond most peoples hearing. I can't hear beyond about 14KHz. Virtually any K77 will go to 14K! FM stations are often very poor quality. In this area there is only a single station that has good quality. That's the PBS classical station WSCL. All the rest are compressed and clipped form maximum "punch". I have a scope connected to my FM tuner and I can not only hear it but I can also "see" it! AL K. Absolutely. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 10, 2006 Share Posted March 10, 2006 Craig: Sure, you are entitled to think what you wish -- I was actually trying to help you with this. Antennas are the single most important component for any receiving-based system, and that is pretty obvious. However, the symptoms or problems we sometimes try to explain with words can often be hard for others to interpret. I wasn't sure if your problems were due to weak reception or something else, and was simply mentioning a cure I had found helpful in the past. As far as I know, there wasn't any name-calling in the post I had written. So, Yes, the 'smart thing' or solution to this problem might be a better antenna; however if that were so obviously the correct thing to do, you didn't even mention it in the post that described this problem. That said, you are probably right. Depending on the load impedance of the circuit in question, a 15k ohm resistor might not be so wild an idea. I have components here (not my design) that use 10k ohm in series with grids, and the response seems completely unchanged. Grid stopper resistors have a very long history behind them, Craig, and they are very commonly used. In the last sentence of your response, you-yourself describe the use of 'my grid stoppers.' Are those in the first or output stage (or maybe both) of the amps, and are they used in those positions as bandaids? All I was trying to do was offer a suggestion for something that might help. I wouldn't tell just anyone to go and throw in some series resistance to help calm possibly hyper-active grid circuits. You have the technical ability to do the work, which wouldn't take more than a few minutes, so I thought I would mention it. Erik Erik, Take your wanna be tube audio design class where it belongs. You try your best to show some prowess in this field. I do not need or want your advise on tube audio design I believe I have stated this about a dozen times here on the forum. What you suggested was ludicrous and just shows how ridicules you really can be. Hey... got a source problem rip your amps and preamps up to fix it Geezzz Craig Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted March 10, 2006 Share Posted March 10, 2006 Leo: "If you want I could make a list of all the possibilities I know of and send them, or post if people are interested." Leo, if it wouldn't be too much trouble, I am also interested in the research you've done with this. As you said, there are so many variables that come into play, and I would like to learn about what you have found. Erik Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 13, 2006 Author Share Posted March 13, 2006 Yes, I know its always been there, but it draws attention to itself... I only notice this on stereo violin sections. It is not the gear. Leo mentioned "electronic oscillation" and that certainly seems to be right on! It is a recording artifact, that is clear. I was just wondering if you guys have run across it, more likely now with your new tweeters. Should I say "welcome to the club"? DM Quote Link to comment Share on other sites More sharing options...
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