sfogg Posted October 19, 2004 Share Posted October 19, 2004 "-3db is a SPL level, not a wattage rating." If you lower the SPL by 3dB the amount of power you are putting into the speaker is half what it was. Conversely if you double the power you put into a speaker it will be playing 3dB louder. (Assuming no power compression) Shawn Quote Link to comment Share on other sites More sharing options...
Deang Posted October 19, 2004 Share Posted October 19, 2004 O.K. Al, stupid question time: why would it be acceptable to use a L-pad on the tweeter, but not the midrange/squawker? Would someone mind taking the time to explain a little about why an autotransformer is preferred. I know PK didn't like L-pads -- but I've never read anywhere where he says why. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted October 19, 2004 Share Posted October 19, 2004 ---------------- On 10/19/2004 3:51:57 PM sunnysal wrote: rick, so you find the 2404H too hot with the ALK crossover? regards, tony ---------------- Tony, Just a tad. I have gone back to my EV T-350 baby baby cheeks until I put an order in at Parts Express. For a couple of dollars it will be a good experiment. There is no doubt in my mind that the 2404H's are a clearer sounding tweeter with more extended highs than either the K-77 or T-350 though. Rick PS: here is a link to an L pad calculator site: http://www.lalena.com/audio/calculator/lpad/ Quote Link to comment Share on other sites More sharing options...
scriven Posted October 19, 2004 Share Posted October 19, 2004 ---------------- On 10/19/2004 2:41:27 PM D-MAN wrote: ---------------- On 10/18/2004 4:15:04 PM scriven wrote: -3db is half the power not half as loud. -10db is usually considered half as loud. ---------------- Scriven, negative on that, good buddy! -3db is a SPL level, not a wattage rating. It's -10x the power, 1/2 the loudness from the reference (0db). DM ---------------- D-Man, It does not matter if it is SPL or wattage. -3db is half the power and -10db is about half the volume. The two work exactly the same. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 20, 2004 Share Posted October 20, 2004 Dean, There's something "magic" about the transformer over an L pad. I'm not sure what it is, but my theory is that it does not divorce the amp damping factor from the driver like a resistor pas does. A tweeter is simply not as important to the character of the sound as the squawker is. The tweeter mostly adds crispness. Since the tweeter is less important then the squawker it can afford to be degraded somewhat where the squawker can't. That's my theory anyhow! AL K. Quote Link to comment Share on other sites More sharing options...
psg Posted October 20, 2004 Share Posted October 20, 2004 ---------------- On 10/19/2004 2:41:27 PM D-MAN wrote: ---------------- On 10/18/2004 4:15:04 PM scriven wrote: -3db is half the power not half as loud. -10db is usually considered half as loud. ---------------- Scriven, negative on that, good buddy! -3db is a SPL level, not a wattage rating. It's -10x the power, 1/2 the loudness from the reference (0db). DM ---------------- DM, you are not saying anything different from Scriven. He is correct. A 10 dB difference is ten times the power, consequently a 3 dB difference is double the power. A 10 dB SPL difference is considered to be a factor of 2 in loudness, but it always seemd bigger than that to me. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 20, 2004 Share Posted October 20, 2004 You guys - hey - don't make me look it up! I would have to then either type more about how smart I am or appologize for being an idiot! Both of which are abhorent to me! DM Quote Link to comment Share on other sites More sharing options...
scriven Posted October 20, 2004 Share Posted October 20, 2004 Peter, First, I agree with you about the 10db figure. That is why I wrote, "-10db is usually considered half as loud". Even if I dont totally agree, that is what is in all the literature and I don't have a better number so I used it. Second, yes we are saying different things. DM is saying that a -3db difference in SPL represents a 1/10 the power going into the speaker. I am contending that the db measurements in SPL and wattage work the same or that a 3db reduction in the SPL is produced buy a 3db wattage decrease. Putting it another way, I am saying the relationship between the wattage going to the speaker and the resultant SPL is linear while DM is saying it is logarithmic. DM, in case you would like to look it up - http://www.audiovideo101.com/dictionary/dictionary.asp?dictionaryid=405 - third paragraph, first sentence. Quote Link to comment Share on other sites More sharing options...
psg Posted October 20, 2004 Share Posted October 20, 2004 ---------------- On 10/20/2004 6:54:48 PM scriven wrote: Peter, First, I agree with you about the 10db figure. That is why I wrote, "-10db is usually considered half as loud". Even if I don’t totally agree, that is what is in all the literature and I don't have a better number so I used it. Second, yes we are saying different things. DM is saying that a -3db difference in SPL represents a 1/10 the power going into the speaker. I am contending that the db measurements in SPL and wattage work the same or that a 3db reduction in the SPL is produced buy a 3db wattage decrease. Putting it another way, I am saying the relationship between the wattage going to the speaker and the resultant SPL is linear while DM is saying it is logarithmic. DM, in case you would like to look it up - http://www.audiovideo101.com/dictionary/dictionary.asp?dictionaryid=405 - third paragraph, first sentence. ---------------- Hmmm. I thought that when he was saying "It's -10x the power, 1/2 the loudness from the reference (0db)." he was refering to your "-10db is usually considered half as loud.". Those statement would be the same. The dB scale is for sound, and thus you can't technically say 3dB more Watts even though we all understand what that means. That might be the source of the misunderstanding? Quote Link to comment Share on other sites More sharing options...
3dzapper Posted October 21, 2004 Share Posted October 21, 2004 "Would someone mind taking the time to explain a little about why an autotransformer is preferred. I know PK didn't like L-pads -- but I've never read anywhere where he says why." Dean, PWK didn't want galloots like us messing with the sound. He refused to put adjustability in because his measurements found them unnecessary. Plus, end users did not have the necessary measuring equipment. Others like JBL and EV did have L-pads in thier high end products including the Khorn clone Patrician. There are some musings on this in the "Dope From Hope" papers. Rick Quote Link to comment Share on other sites More sharing options...
Daveman Posted October 30, 2004 Share Posted October 30, 2004 Al, Ive just purchased a pair of CP25s and would like to see the schematic for using the switchable pad in your A series network. Dave Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 30, 2004 Share Posted October 30, 2004 Dave, Here's the info on the switchable attenuator. All the resistors are 5% 1W film. It will handle up to 5W continuous from the source. It can be used with any tweeter so long as it is 8 Ohms. Al K. Quote Link to comment Share on other sites More sharing options...
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