hi!
i have some questions!
there isnt much discussion on details on distortion,most speaker books dont cover this in detail<mine doesnt>
its easy to find general ideas,but harder to find exact details especialy on the net
what causes IM? is it magnet nonlinearities or cone/?
1-in push pull,woofers cancel their own 2nd harmonic distortion..
if so,what is going on in the spring mass system to cause this in ths first place!
-frequency doubling occurs on woodwind instruments also when u dont play it properly lol-
2-what sort of distortion do the magnet circuits cause/? harmonic structures/ or random noise
3-what sort do the actual cones make/? not much until they flex/?
4-when operated below Fs,speakers generally exhibit 'frequency doubling' like <1>is this simply the result of a floppy suspension ..whats going on here Exactly
5-why do speakers seem to 'bungy' really far when u drive the amp too hard,theres no reason for it to go REALY excessive excursion,or is this simply me playing too low sinewaves-is it because of the damping factor changing,or something
-and why does my jbl have such high quality it doesnt sound bad when tuned below Fs.saying its 'higher quality' isnt enough detail for me.
cya!
:^)
i have some questions!
there isnt much discussion on details on distortion,most speaker books dont cover this in detail<mine doesnt>
its easy to find general ideas,but harder to find exact details especialy on the net
what causes IM? is it magnet nonlinearities or cone/?
1-in push pull,woofers cancel their own 2nd harmonic distortion..
if so,what is going on in the spring mass system to cause this in ths first place!
-frequency doubling occurs on woodwind instruments also when u dont play it properly lol-
2-what sort of distortion do the magnet circuits cause/? harmonic structures/ or random noise
3-what sort do the actual cones make/? not much until they flex/?
4-when operated below Fs,speakers generally exhibit 'frequency doubling' like <1>is this simply the result of a floppy suspension ..whats going on here Exactly
5-why do speakers seem to 'bungy' really far when u drive the amp too hard,theres no reason for it to go REALY excessive excursion,or is this simply me playing too low sinewaves-is it because of the damping factor changing,or something
-and why does my jbl have such high quality it doesnt sound bad when tuned below Fs.saying its 'higher quality' isnt enough detail for me.
cya!
:^)
reply
Well there are many types of distortion.
Over excersion of a bass driver results in 'poping' or 'thud' sound every time it moves in and out,usually caused by the voice coil former hitting the back plate.
A constant buzzing sound/raspy noise coming from a speaker is either an overheated voice coil rubbing in the pole piece,any part of the cone/surround/dampener/voice coil that is torn and flaps about,or a shifted magnet,causing the voice coil former to rub.
Harmonic distortion and Intermodulation distortion: these types of distortion are characterized by the presence of frequencies in the speaker output which are not in the electrical input.
Example: a booming resonanting bass sound,resulted from a badly dampened speaker enclosure.
Well any sound that wasn't present in the original recording is termed distortion.
Transient Response: the transient responce is the time delay as the speaker begins from rest to respond to a sudden sharp electrical pulse.A stiff cone and suspesion act to resist movement,so the speaker may respond slower and cause a delay in the reproduced sound.
Clipping: Occurs when the speaker cone cannot move as far required by the audio signal.When the cone'bottoms out' the speaker is not able to accurately reproduce the sound.
Phase distortion: that is phase differences between frequencies that were not present in the original signal,do not seem to have a noticable effect on the quality of the sound itself.They do effect the stereo image which can be blurred o even rendered tatally inderminate except for the left and right postions.
Doppler Distortion: occurs where the pitch of the high frequencies was suscessively raised and lowered at forward and bacward movement of the cone.
Harmful distortion to the loudspeaker,which leads to permenant damage to the loudspeaker: clipping,over excersion,and DC.
A very clipped signal to a loudspeaker is mostly to burn the voice coil and/or over excersion.
A fault in the amplifier sends speaker frying DC to the loudspeaker either burning the voice completely = no sound at all from speaker,or partially damage the voice coil Dc burn/scourch marks on the voice coil and an over heated voice coil,but still sound comes out of the speaker,but will be quieter.Both types cause permenant damage to the loudspeaker.
And last but not least.Accidental damage to the cone. example foot torn the speaker cone or dented in the dustcap[people who are careless and don't put the covers in the speakers].And also spilled liquid on a loudspeaker cone,either from careless people at a party/disco or If some stupid person put their drink on the speaker cabinet and by mistake knocked it over.
This would result in a weaker cone,ending up in a torn cone,which would mean either re-cone or bin the loudspeaker driver.
Well there are many types of distortion.
Over excersion of a bass driver results in 'poping' or 'thud' sound every time it moves in and out,usually caused by the voice coil former hitting the back plate.
A constant buzzing sound/raspy noise coming from a speaker is either an overheated voice coil rubbing in the pole piece,any part of the cone/surround/dampener/voice coil that is torn and flaps about,or a shifted magnet,causing the voice coil former to rub.
Harmonic distortion and Intermodulation distortion: these types of distortion are characterized by the presence of frequencies in the speaker output which are not in the electrical input.
Example: a booming resonanting bass sound,resulted from a badly dampened speaker enclosure.
Well any sound that wasn't present in the original recording is termed distortion.
Transient Response: the transient responce is the time delay as the speaker begins from rest to respond to a sudden sharp electrical pulse.A stiff cone and suspesion act to resist movement,so the speaker may respond slower and cause a delay in the reproduced sound.
Clipping: Occurs when the speaker cone cannot move as far required by the audio signal.When the cone'bottoms out' the speaker is not able to accurately reproduce the sound.
Phase distortion: that is phase differences between frequencies that were not present in the original signal,do not seem to have a noticable effect on the quality of the sound itself.They do effect the stereo image which can be blurred o even rendered tatally inderminate except for the left and right postions.
Doppler Distortion: occurs where the pitch of the high frequencies was suscessively raised and lowered at forward and bacward movement of the cone.
Harmful distortion to the loudspeaker,which leads to permenant damage to the loudspeaker: clipping,over excersion,and DC.A very clipped signal to a loudspeaker is mostly to burn the voice coil and/or over excersion.
A fault in the amplifier sends speaker frying DC to the loudspeaker either burning the voice completely = no sound at all from speaker,or partially damage the voice coil Dc burn/scourch marks on the voice coil and an over heated voice coil,but still sound comes out of the speaker,but will be quieter.Both types cause permenant damage to the loudspeaker.
And last but not least.Accidental damage to the cone. example foot torn the speaker cone or dented in the dustcap[people who are careless and don't put the covers in the speakers].And also spilled liquid on a loudspeaker cone,either from careless people at a party/disco or If some stupid person put their drink on the speaker cabinet and by mistake knocked it over.
This would result in a weaker cone,ending up in a torn cone,which would mean either re-cone or bin the loudspeaker driver.
Re: reply
How come we do not hear more about this? Is it becuase it has been resolved by current designs, is not an issue with popular enclosure designs, etc?
Bull said:
How come we do not hear more about this? Is it becuase it has been resolved by current designs, is not an issue with popular enclosure designs, etc?
The motor is one source of distrortion.
The symmetry of the magneic field largely affects 2nd order distortion.
Even order distortion is also generated by flux modulation i.e. the field of the voice-coil is weakening and strengthening the filed of the magnet.
The shape of the field at both ends of the gap influence 3rd order distortion.
The family of JBL drivers you are using have a magnetic gap design with very low distortion in mind.
As you already mentioned they have approx 1% THD @ 60 Watts which can be regarded as excellent. Not to mention that a linear x-max of almost +- 8mm is very large for a P.A. driver.
See also: http://www.jblpro.com/pub/technote/tn_v1n18.pdf
Regards
Charles
The symmetry of the magneic field largely affects 2nd order distortion.
Even order distortion is also generated by flux modulation i.e. the field of the voice-coil is weakening and strengthening the filed of the magnet.
The shape of the field at both ends of the gap influence 3rd order distortion.
The family of JBL drivers you are using have a magnetic gap design with very low distortion in mind.
As you already mentioned they have approx 1% THD @ 60 Watts which can be regarded as excellent. Not to mention that a linear x-max of almost +- 8mm is very large for a P.A. driver.
See also: http://www.jblpro.com/pub/technote/tn_v1n18.pdf
Regards
Charles
Re: Re: reply
Doppler distortion was one of the subjects that Paul Klipsch had focused upon. The problem still exists but is largely ignored. 2 way systems with small woofer/mids are the worst offenders. A 3 way system with the lower crossover frequency above about 100Hz will minimize the problem. Horn systems, with their greater efficiency, will have minimal doppler distortion.
I have never heard anything coming out of a speaker that I could point to and say, "That's doppler." Maybe it isn't as audible as Klipsch made it out to be.
amo said:
Doppler distortion was one of the subjects that Paul Klipsch had focused upon. The problem still exists but is largely ignored. 2 way systems with small woofer/mids are the worst offenders. A 3 way system with the lower crossover frequency above about 100Hz will minimize the problem. Horn systems, with their greater efficiency, will have minimal doppler distortion.
I have never heard anything coming out of a speaker that I could point to and say, "That's doppler." Maybe it isn't as audible as Klipsch made it out to be.
Play a low frequency tone on the woofers using reasonable
power levels to cause high cone excursion... then mix
some vocals with that tone and tell what what the voice
sounds like. /heheh
Talk into a fan?
power levels to cause high cone excursion... then mix
some vocals with that tone and tell what what the voice
sounds like. /heheh
Talk into a fan?
So.... would this be another reason to use multiple drivers either to a) split the frequencies into portions so that higher sounds are not pushed by cone excursion of lower frequencies, or b) to send the same signal to many wide range drivers, so that each produces much less cone excurion to produce the same total sound??????? If thats the case, which is better?
Re: Re: Re: reply
Are there any papers we can look at?
Sounds more like diffraction patterns on the emitted waves...
🙂ensen.
Bill Fitzpatrick said:
Are there any papers we can look at?
thylantyr said:Play a low frequency tone on the woofers using reasonable
power levels to cause high cone excursion... then mix
some vocals with that tone and tell what what the voice
sounds like. /heheh
Talk into a fan?
Sounds more like diffraction patterns on the emitted waves...
🙂ensen.
Re: Re: Re: Re: reply
Lack of Doppler distortion (as defined by Klipsch) is certainly one reason for going to a 3 way system. Multiple drivers, as in a line array, would certainly help if the line array was full range but given the problems (real or imaginary) of line arrays the solution might be worse than the problem.
I'm sure the Audio Engineering Society offer some reprints but I haven't found anything on the net.
amo said:
Lack of Doppler distortion (as defined by Klipsch) is certainly one reason for going to a 3 way system. Multiple drivers, as in a line array, would certainly help if the line array was full range but given the problems (real or imaginary) of line arrays the solution might be worse than the problem.
purplepeople said:
I'm sure the Audio Engineering Society offer some reprints but I haven't found anything on the net.
bull: you told me what i already know
phase-what you say is interesting and what i was interested in
there is a lack of discussion or material on this topic
🙂 🙂
phase-what you say is interesting and what i was interested in
there is a lack of discussion or material on this topic
🙂 🙂
Re: Re: Re: reply
Strange then that no one's yet noticed just how bad the speakers sound.
Could it be that the legendary Paul Klipsch is mistaken about this?
Now I'm pretty sure that my Nonsuch 4 full-range speaker is an even worse offender than 2 way systems with small woofer/mids. In fact, If Klipsch is right about Doppler distortion, my speakers should be virtually intolerable to listen to.Bill Fitzpatrick said:
Strange then that no one's yet noticed just how bad the speakers sound.
Could it be that the legendary Paul Klipsch is mistaken about this?
Re: Re: Re: Re: reply
No offence, but I think I'm going to take PWK's opinion over yours. He had the (decades of) experience, the engineering training, the test and measurement facilities and people like Keele (amongst others) working for him. And from what I've read of your posts here and elsewhere, you definitely don't.
7V said:
No offence, but I think I'm going to take PWK's opinion over yours. He had the (decades of) experience, the engineering training, the test and measurement facilities and people like Keele (amongst others) working for him. And from what I've read of your posts here and elsewhere, you definitely don't.
Re: Re: Re: Re: reply
I read his paper in the AES many, many years ago. I don't recall what he said about the subjective experience; maybe nothing. It could have easily been just an advertising/academic ploy but don't quote me on that. Then, maybe, it was all theoretical and the effect wasn't audible.
Anyone wanting more info could probably get if from Klipsch.
7V said:
I read his paper in the AES many, many years ago. I don't recall what he said about the subjective experience; maybe nothing. It could have easily been just an advertising/academic ploy but don't quote me on that. Then, maybe, it was all theoretical and the effect wasn't audible.
Anyone wanting more info could probably get if from Klipsch.
lowther full range vs 3way debate continues 
people can/do make mistakes even heros like klipsch Lol dont forget...
perhaps an exxageration,every mad scientist has his own view
</me continues to listen to his 1980s philips 2ways>
there will be some articles somewhere on this,aes.
🙂
people can/do make mistakes even heros like klipsch Lol dont forget...
perhaps an exxageration,every mad scientist has his own view
</me continues to listen to his 1980s philips 2ways>
there will be some articles somewhere on this,aes.
🙂
Paper chase
I just wish the AES would web-publish their journal. I'm not asking for current, but maybe 6-12 months out would be good.
🙂ensen.
I just wish the AES would web-publish their journal. I'm not asking for current, but maybe 6-12 months out would be good.
🙂ensen.
i know :-S
cos if i start buying aes articles,il want toooo many
theres about 15horn ones i want-from low frequency driver specifications to,horn folding and ducts.
and thats only 1 subject im interested in!
but if they were free,i would doubt the quality of content😎
cos if i start buying aes articles,il want toooo many
theres about 15horn ones i want-from low frequency driver specifications to,horn folding and ducts.
and thats only 1 subject im interested in!
but if they were free,i would doubt the quality of content😎
Re: Paper chase
If anyone runs a woofer up to 2kHZ or above, surely the Doppler distortion must be apparent. If it's not apparent, what does that mean? Is it masked by something else? If so what?
What if we take four identical full-range drivers and mount them on two large open baffles?
Baffle 1 - we add a crossover so that the highs go through one driver and the lows through the other.
Baffle 2 - we play full-range (well, we could add a crossover with a frequency above the range of the drivers, just to get some similar components in the circuit).
That would be a test for Doppler distortion, wouldn't it? Has anyone read of anyone who's done such a test?
Bull's post on the first page identifies many different types of distortion. Many of us are familiar with the sound of many of these. How about Doppler?
That would be nice. Meanwhile, we've still got ears.purplepeople said:
If anyone runs a woofer up to 2kHZ or above, surely the Doppler distortion must be apparent. If it's not apparent, what does that mean? Is it masked by something else? If so what?
What if we take four identical full-range drivers and mount them on two large open baffles?
Baffle 1 - we add a crossover so that the highs go through one driver and the lows through the other.
Baffle 2 - we play full-range (well, we could add a crossover with a frequency above the range of the drivers, just to get some similar components in the circuit).
That would be a test for Doppler distortion, wouldn't it? Has anyone read of anyone who's done such a test?
Bull's post on the first page identifies many different types of distortion. Many of us are familiar with the sound of many of these. How about Doppler?
Don't quite get it, yet
If I undertand this correctly, the mere fact that the cone moves away from my ear causes the "red" shift in the frequency during that part of the cycle and then when it moves towards me, it causes a "blue" shift in the sound.
So, for a pure sine wave sound input, the driver outputs a smeared note that is simultaneously "sharp" and "flat" relative to the input frequency. A similar effect would be to play the notes B, C and C# on a violin.
I can imagine that this effect is extremely small and may be nearly impossible to measure.
Case in point: An ambulance passes you on the street. As it moves into the distance, the notes from the siren get lower and lower, but the rate of frequency change diminishes the farther it is. The moment of greatest note change is the point at which the ambulance has just passed.
It follows that we would have to be directly beside the woofer and have the cone move well past our position for us to notice the effect. The fact that the we are at a very large distance relative to excursion would be analagous to the ambulance being at some far off distance. We just can't hear the "red" and "blue" shifts at those distances.
🙂ensen.
Bull said:
If I undertand this correctly, the mere fact that the cone moves away from my ear causes the "red" shift in the frequency during that part of the cycle and then when it moves towards me, it causes a "blue" shift in the sound.
So, for a pure sine wave sound input, the driver outputs a smeared note that is simultaneously "sharp" and "flat" relative to the input frequency. A similar effect would be to play the notes B, C and C# on a violin.
I can imagine that this effect is extremely small and may be nearly impossible to measure.
Case in point: An ambulance passes you on the street. As it moves into the distance, the notes from the siren get lower and lower, but the rate of frequency change diminishes the farther it is. The moment of greatest note change is the point at which the ambulance has just passed.
It follows that we would have to be directly beside the woofer and have the cone move well past our position for us to notice the effect. The fact that the we are at a very large distance relative to excursion would be analagous to the ambulance being at some far off distance. We just can't hear the "red" and "blue" shifts at those distances.
🙂ensen.
some AES papers
May I offer to all of you some intersting papers on the subject:
http://www.klippel.de/background/default.asp
May I offer to all of you some intersting papers on the subject:
http://www.klippel.de/background/default.asp
- Status
- Not open for further replies.