Klipschguy Posted February 2, 2023 Share Posted February 2, 2023 I have a pair of K55 drivers. One driver sounds distorted (garbled would be a reasonable description) during some passages when played full range with no horn. The volume is not very loud for the test, but there is bass in the signal. With a capacitor and a horn lens it sounds fine (uncertain about at very high levels though). Thoughts? Maybe the diaphragm tends to bottom due very close tolerances - even at low levels? Quote Link to comment Share on other sites More sharing options...
CWOReilly Posted February 2, 2023 Share Posted February 2, 2023 Has any debris entered the driver? Any corrosion? 1 Quote Link to comment Share on other sites More sharing options...
henry4841 Posted February 2, 2023 Share Posted February 2, 2023 Should never be used as described without horn attached and a cap to prevent low notes that could overdrive the diaphragm. 1 Quote Link to comment Share on other sites More sharing options...
mustang_flht Posted February 2, 2023 Share Posted February 2, 2023 Hello ! Yes, like @CWOReilly checked if there is no dust or debris at the level of the diaphragm. here the cut of a K55V (I don't know which model you have K55M, V ...) there is little space between the diaphragm and the phasing plug: a single piece of debris can make noise, even at low level. 1 Quote Link to comment Share on other sites More sharing options...
wuzzzer Posted February 2, 2023 Share Posted February 2, 2023 The lesson here is: don’t send a full range signal to a driver that isn’t designed to reproduce a full range signal. 1 Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted February 2, 2023 Share Posted February 2, 2023 1 hour ago, Klipschguy said: I have a pair of K55 drivers. One driver sounds distorted (garbled would be a reasonable description) during some passages when played full range with no horn. The volume is not very loud for the test, but there is bass in the signal. With a capacitor and a horn lens it sounds fine (uncertain about at very high levels though). Thoughts? Maybe the diaphragm tends to bottom due very close tolerances - even at low levels? Stop if you like these drivers!! They need the 'back pressure' of the horn as well as a roll-off to keep them in their range. Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted February 2, 2023 Author Share Posted February 2, 2023 Please know. I am not cranking up the volume at all. The K55 is specified to have frequency response to 75Hz. (I would not do the same with one of my Altec drivers.) A low level, full range signal helps me identify issues with drivers that may be difficult to detect. The volume is low enough to put the driver throat directly to my ear like a headphone. There is an issue, I am just trying to figure out if it is a problem. The driver is a K55V dual phase plug. Thank you for your replies. Should I disassemble the driver??? (I have replaced a number of diaphragms in the past without issues). I am a bit concerned about decreasing the alnico magnetic charge by separating the plates. The drivers have never been opened. One driver passes the full range, low-level-to-the-ear-test: the other does not. Quote Link to comment Share on other sites More sharing options...
Deang Posted February 2, 2023 Share Posted February 2, 2023 25 minutes ago, Klipschguy said: The K55 is specified to have frequency response to 75Hz Where did you read that? It has a plane wave tube response down to 110Hz. The tube provides a resistive load. As long as you don't drop the driver or bang it into something, the magnetic charge will be fine. I would change both diaphragms, and since you've done this before, you probably know to clean out the magnetic gap. Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted February 2, 2023 Author Share Posted February 2, 2023 19 minutes ago, Deang said: Where did you read that? It has a plane wave tube response down to 110Hz. The tube provides a resistive load. As long as you don't drop the driver or bang it into something, the magnetic charge will be fine. I would change both diaphragms, and since you've done this before, you probably know to clean out the magnetic gap. Altas PD-5VH vs K55 Well, I guess I heard it here from our friend, Bob Crites aka BEC (rest in peace, you are missed my friend). Click on the link and scroll down to post #11. Quote Link to comment Share on other sites More sharing options...
jcn3 Posted February 2, 2023 Share Posted February 2, 2023 25 minutes ago, Klipschguy said: Altas PD-5VH vs K55 Well, I guess I heard it here from our friend, Bob Crites aka BEC (rest in peace, you are missed my friend). Click on the link and scroll down to post #11. according to that thread, bob said that a user named dodger said that -- it's not clear whether he believed it since the topic was related to the upper frequency extension. Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted February 2, 2023 Author Share Posted February 2, 2023 3 hours ago, jcn3 said: according to that thread, bob said that a user named dodger said that -- it's not clear whether he believed it since the topic was related to the upper frequency extension. …rabbit trail dodger did indeed claim it, but Bob also stated dodger “faxed him an Altlas spec sheet” which BEC states “does in fact specify” a low frequency extension to 75Hz. Whether or not he believes the spec sheet from Atlas… Anyway, any more thoughts on my driver are appreciated. Quote Link to comment Share on other sites More sharing options...
mustang_flht Posted February 2, 2023 Share Posted February 2, 2023 if there is no debris between the diaphragm and the phase plug. You disassemble the diaphragm and clean the passage of the coil between the plates of the magnetic system with a small thin paper. You will take the opportunity to examine the coil: see if it rubs in the passage between the plates, see if it is swollen and or burned: if it has heated it may rub between the plates of the magnetic system and make a small friction noise. for electrical and sound tests, even at low level: I advise you to put a 10, 20 or 30 µF bipolar safety capacitor in series depending on the driver's impedance 2 Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted February 2, 2023 Author Share Posted February 2, 2023 5 minutes ago, mustang_flht said: if there is no debris between the diaphragm and the phase plug. You disassemble the diaphragm and clean the passage of the coil between the plates of the magnetic system with a small thin paper. You will take the opportunity to examine the coil: see if it rubs in the passage between the plates, see if it is swollen and or burned: if it has heated it may rub between the plates of the magnetic system and make a small friction noise. Fantastic reply, Mustang! Thank you. I will check it out. 1 Quote Link to comment Share on other sites More sharing options...
mustang_flht Posted February 2, 2023 Share Posted February 2, 2023 no problem, it's normal 😉 I added a little security phrase for your driver in my message above ☺️ 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.