S

sparky77

Full Audioholic
The easiest way to get good bass extension and imaging is in my opinion, still the old way the highclass speakers were built, big woofer, mid, and tweeter. I was strongly considering dual 8's, but decided to go for the old school look, and it did have something to do with wife exceptance factor, she really liked the old advent speakers she had. Tested responce in room goes well below the rated 40hz of the woofer, including the room gain I've measured them down to 28hz. Although my current speakers may eventually put to sorround duty and replaced by dual 10's.
 
TLS Guy

TLS Guy

Audioholic Slumlord
Cost, Cost and Cost. You have the expense of a large driver and a lot of extra crossover components. To top it off most of those old three ways were not very good. Getting the band pass crossover to the midrange is a headache. You have driver overlap with comb filtering problems. The phase and group delay problems are very significant and take a lot of patience and R & D to sort out. To say nothing of the fact that there has always been a dearth of really good dedicated midrange drivers available. Really I have found the very expensive Dynaudio D 76 excellent but it is NLA. I have used the Jordan Watts module with success as a mid, and so have others. Peerless have just introduced a new mid, but of course I have no experience of it.

The short of it is that to get the bass extension and power handling of a three way with a large woofer, you open up a new set of challenges. Properly solving those will put Joe into debt.
 
WmAx

WmAx

Audioholic Samurai
Really I have found the very expensive Dynaudio D 76 excellent but it is NLA. I have used the Jordan Watts module with success as a mid, and so have others. Peerless have just introduced a new mid, but of course I have no experience of it.
As a suggestion, the Infinity 10PR80BZQ-FW02 4" mid (really 3.1" - 4" is the frame diameter) is an excellent midrange for the 400Hz-3000Hz band. At 3000Hz, at 60 degrees, response is almost identical to on axis response. Waterfall is textbook perfect. 1st resonance appears at 10kHz. Almost +/- 1dB up to 4khz, on a diffraction free mounting. It is a ceramic laminate cone driver: 40 percent ceramic and 60 percent aluminum by thickness. Distortion vs. SPL is sufficient for a high - end application. Sensitivity is 90dB at 1 watt/1meter, on a large baffle. You do have to remove the magnetic shield can on the back. It appears they are not attached firmly to the sides, thus causing a subtle rattle in some instances.

-Chris
 
WmAx

WmAx

Audioholic Samurai
In short he wants 90% + of the optimal listening experience on by far the major percentage of his recordings with minimal hassle.
Such an end (90 percent optimal listening experience) seems a bit out of reach under the current circumstances.
Now as to dopler distortion, that is very real. You can quantify it. However it is one of audio mysteries that it does not bother people. The ear does not seem very sensitive to it, thank goodness. There was a huge amount of ink spilled about this back in the fifties, and then people realized it was not one of the loudspeaker faults, that caused listeners displeasure. I have no clue why, you would think it would
Bother, it does, under the specific conditions that I outlined earlier. It is not an issue at low SPL levels under normal circumstances.

-Chris
 
S

sparky77

Full Audioholic
you can't tell me that group delays aren't a significant factor in tl speakers, but the human ear has an amazing way of dealing with the difference, as for the comb effect it does take more carefull considerations in the crossover, I do give you that much, as for cost, that isn't always a factor there are a lot of great speaker components that won't break the bank. I'm not saying the goldwoods I used in my build are top notch, but they sure as heck sound better than most of the oem speakers from the big box stores. I only choosed them because of a tight budget, and I'm definately going to check out the higher grade speakers of theirs. By the way, the cheap sealed back midrange available from Parts Place, sounds very good, excellent imaging and clarity for such a cheap component.
 
TLS Guy

TLS Guy

Audioholic Slumlord
you can't tell me that group delays aren't a significant factor in tl speakers, but the human ear has an amazing way of dealing with the difference, as for the comb effect it does take more carefull considerations in the crossover, I do give you that much, as for cost, that isn't always a factor there are a lot of great speaker components that won't break the bank. I'm not saying the goldwoods I used in my build are top notch, but they sure as heck sound better than most of the oem speakers from the big box stores. I only choosed them because of a tight budget, and I'm definately going to check out the higher grade speakers of theirs. By the way, the cheap sealed back midrange available from Parts Place, sounds very good, excellent imaging and clarity for such a cheap component.
The fact a speaker is a TL has nothing to do with group delay, adding crossovers especially analog ones with high orders does.
 
S

sparky77

Full Audioholic
That depends if your using the transmission line as sort of an inifinate baffle with no real ported output, or if your using as one long port as opposed to rear horn loading, the later of the two introduce group delays that have higher delay times than the typical vented enclosure. If I remember right there is an article somewhere on the audiohilics site, that gives a little light to the subject about how little it really means in actual audibility, when I have the time to search for it I will post it, unless somebody else can bring it to light for all of us. I'm not gonna say one type of alignment is better than another, they all produce they're own benefits and deficiency's, and most people would be none the wiser due to how the human ear peceives sound, it is remarkable adaptive. Hence the topics about double blind tests and the statements that the hearing memmory is only about 4 seconds.

This is a subject that we could all argue on for months and never come to a scientific conclusion, because, well, their is no real scientific proof of any of it, acoustics is about as subjective of a science the biochemistry of the brain, and as difficult to disprove as quantum physics.

In my honest opinion, it doesn't really matter if you use two 8's or one 10, if you use the proper alignment coupled with the right midrange if necessary and the appropriate crossover, you will get as close to equal sounding speaker systems as you can get providing all other factors are equal, which in all practicallity, will most likely never be equal.
 
WmAx

WmAx

Audioholic Samurai
This is a subject that we could all argue on for months and never come to a scientific conclusion, because, well, their is no real scientific proof of any of it, acoustics is about as subjective of a science the biochemistry of the brain, and as difficult to disprove as quantum physics.
Are you sure you did not make an error in this statement? Perhaps you meant to say something else? Of course, many aspects of loudspeaker parameters have been studied under scientifically valid perceptual tests with statistically significant results demonstrating probabilities of audibility with various measurable aspects.

-Chris
 
TLS Guy

TLS Guy

Audioholic Slumlord
That depends if your using the transmission line as sort of an inifinate baffle with no real ported output, or if your using as one long port as opposed to rear horn loading, the later of the two introduce group delays that have higher delay times than the typical vented enclosure. If I remember right there is an article somewhere on the audiohilics site, that gives a little light to the subject about how little it really means in actual audibility, when I have the time to search for it I will post it, unless somebody else can bring it to light for all of us. I'm not gonna say one type of alignment is better than another, they all produce they're own benefits and deficiency's, and most people would be none the wiser due to how the human ear peceives sound, it is remarkable adaptive. Hence the topics about double blind tests and the statements that the hearing memmory is only about 4 seconds.

This is a subject that we could all argue on for months and never come to a scientific conclusion, because, well, their is no real scientific proof of any of it, acoustics is about as subjective of a science the biochemistry of the brain, and as difficult to disprove as quantum physics.

In my honest opinion, it doesn't really matter if you use two 8's or one 10, if you use the proper alignment coupled with the right midrange if necessary and the appropriate crossover, you will get as close to equal sounding speaker systems as you can get providing all other factors are equal, which in all practicallity, will most likely never be equal.
Of course you want port output, that is the whole point of a TL. If done correctly it will support output below 100 Hz to F3 2db to 3db better than other alignments. It also usually gives a slightly lower F3. The TL has nothing in common with horns. The TL is a highly specialized variant of the Gedeckt organ pipe. The big news in recent years is that the VAS of the driver has a relationship to the volume of air in the pipe Vp. So pipe volume, length, taper, driver position and fill weight all have to be calculated correctly to the driver, or drivers.
 
3db

3db

Audioholic Overlord
I know what Doppler effect is.. listener (point of reference) standing still, pitch changes of the train whistle as it passes by the listener. Sound waves moving from compression to expansion relative the listewning position.

I want to know, how this manifests it self in a speaker. Can be heard? I'm thinking yes because I think I expreinced it with my old Technic towers, SB-T200 that I used to own. I noticed a change in pitch when I back off the volume during excessive loudness, greater than 88db.
 
WmAx

WmAx

Audioholic Samurai
I know what Doppler effect is.. listener (point of reference) standing still, pitch changes of the train whistle as it passes by the listener. Sound waves moving from compression to expansion relative the listewning position.

I want to know, how this manifests it self in a speaker. Can be heard? I'm thinking yes because I think I expreinced it with my old Technic towers, SB-T200 that I used to own. I noticed a change in pitch when I back off the volume during excessive loudness, greater than 88db.
I did specify a set of circumstances where it can occur in a past post I have made in this thread.

It should also be noted that the term 'Doppler Effect' may be an erroneous term to use in reference to the actual phenom that occurs. In addition, other distortions also manifest themselves during the same circumstances as occur with the subject here.

Here is an extremely informative article on the effect in general:

http://sound.westhost.com/doppler.htm

-Chris
 
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TLS Guy

TLS Guy

Audioholic Slumlord
I know what Doppler effect is.. listener (point of reference) standing still, pitch changes of the train whistle as it passes by the listener. Sound waves moving from compression to expansion relative the listewning position.

I want to know, how this manifests it self in a speaker. Can be heard? I'm thinking yes because I think I expreinced it with my old Technic towers, SB-T200 that I used to own. I noticed a change in pitch when I back off the volume during excessive loudness, greater than 88db.
You won't perceive it as change in pitch, th changes are too fast.

Lets say we have a midbass woofer producing a 60 HZ tone. This woofer cone will be moving to and fro, constantly changing is velocity vector through 360 degrees. Now if we superimpose a 1k tone, that tone is emanated from a cone alternately moving towards you and away from you. So as the cone moves towards you the I 1K tone is raised in frequency (pitch) and as the cone moves away from you it is lowered in pitch. It is just like passing the train with it's horn blowing.

I would not make too much of this, especially concerning my experience with the JW driver. That is a full ranger with a 4 inch cone, the suspension is three Beryllium cantilevers giving the driver a huge xmax. Those little drivers have a quite astonishing bass response. The cone obviously has to make large excursions white producing sounds up to 20K. The sound is still very clean. I personally believe the changes of pitch are too fast for the brain to perceive and it averages them. I think this is why the topic does not come up much. If you look at a HF waveform coming from a driver reproducing an LF tone, your first response is ,Heavens, that must sound awful. However there are huge numbers of speakers with small bass mids in use, and the topic is seldom raised.
 
WmAx

WmAx

Audioholic Samurai
I would not make too much of this, especially concerning my experience with the JW driver. That is a full ranger with a 4 inch cone, the suspension is three Beryllium cantilevers giving the driver a huge xmax. Those little drivers have a quite astonishing bass response. The cone obviously has to make large excursions white producing sounds up to 20K. The sound is still very clean. I personally believe the changes of pitch are too fast for the brain to perceive and it averages them. I think this is why the topic does not come up much. If you look at a HF waveform coming from a driver reproducing an LF tone, your first response is ,Heavens, that must sound awful. However there are huge numbers of speakers with small bass mids in use, and the topic is seldom raised.
Under no circumstance, have I ever come across any small size speaker driver that could 'cleanly' produce dynamic LF transients and keep a realistic upper midrange/treble at the same time. It's not even possible, so far as I can see, based on simply other non-linear distortion mechanisms that will manifest if such a driver is used at such high excursion levels relative to the motor and suspension linearities. I suppose I could see a really good example working at the 70dB SPL range; but much above that and serious problems seem bound to occur. Such drivers need the LF filtered out for any optimal sound reproduction. Even in this case, LF(let's define that as 30Hz-40Hz) at any considerable SPL for dynamics will have substantial non-linear distortion(s). I will gladly measure any small driver example, if you so desire to send it, if you are confident it is sufficient. I propose that THD and IMD distortion artifacts in general will make this driver useless for true high-fidelity purposes for a wide LF band in a stereo system required to produce LF dynamics or any considerable LF SPL.

-Chris
 
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F

fmw

Audioholic Samurai
Under no circumstance, have I ever come across any small size speaker driver that could 'cleanly' produce dynamic LF transients and keep a realistic upper midrange/treble at the same time.
-Chris
No, but an array of small speakers can. I remember the "sweet 16" speakers of the 1950's. They were an array of 16 little 4" radio speakers mounted to a baffle. They sounded pretty good.
 
WmAx

WmAx

Audioholic Samurai
I know what Doppler effect is.. listener (point of reference) standing still, pitch changes of the train whistle as it passes by the listener. Sound waves moving from compression to expansion relative the listewning position.

I want to know, how this manifests it self in a speaker. Can be heard? I'm thinking yes because I think I expreinced it with my old Technic towers, SB-T200 that I used to own. I noticed a change in pitch when I back off the volume during excessive loudness, greater than 88db.
BTW, since this was a 3 way in which you heard this 'distortion', it does not seem likely it could be phase modulation distortion(a.k.a. misnomer Doppler). I think in your example, it was likely good ol' fashioned inter-modulation distortion, a result of an insufficiently steep high pass filter on the mid-range(or even on the tweeter); the mid-range(and tweeter) motor/suspension was probably optimized for extremely low level excursion relative to the bandwidth and filter that was used; and the insufficient filter was allowing too much lower frequency energy, causing the unit(s) to exceed linear motor/suspension range(s).

-Chris
 
WmAx

WmAx

Audioholic Samurai
No, but an array of small speakers can. I remember the "sweet 16" speakers of the 1950's. They were an array of 16 little 4" radio speakers mounted to a baffle. They sounded pretty good.
I don't think that simply 16 of those would match a high quality modern subwoofer, but maybe if you use 100 of them per side..... :) Yes, one could use enough small drivers, and have sufficient LF bass. But arrays of vast numbers of small drivers is not the subject I was discussing.

-Chris
 
TLS Guy

TLS Guy

Audioholic Slumlord
Under no circumstance, have I ever come across any small size speaker driver that could 'cleanly' produce dynamic LF transients and keep a realistic upper midrange/treble at the same time. It's not even possible, so far as I can see, based on simply other non-linear distortion mechanisms that will manifest if such a driver is used at such high excursion levels relative to the motor and suspension linearities. I suppose I could see a really good example working at the 70dB SPL range; but much above that and serious problems seem bound to occur. Such drivers need the LF filtered out for any optimal sound reproduction. Even in this case, LF(let's define that as 30Hz-40Hz) at any considerable SPL for dynamics will have substantial non-linear distortion(s). I will gladly measure any small driver example, if you so desire to send it, if you are confident it is sufficient. I propose that THD and IMD distortion artifacts in general will make this driver useless for true high-fidelity purposes for a wide LF band in a stereo system required to produce LF dynamics or any considerable LF SPL.

-Chris
Chris,
You are dead wrong. That driver is a VERY accurate high fidelity driver. It held a strong nitch position for around 25 years. It was especially revered in the Far East, where it still is. There are sites, which I can't decipher, still devoted to this driver. I have used it in times past in big installation as the mid, eight a side. They were used in the remarkable large installation at the military band school Kneller Hall.

I confessed yesterday to be a full ranger at heart, and I'm unrepentant. I recently had a lesson in totally intuitive audio engineering from my 85 year old father. He recalled the time when the late Donald Chave, who we knew well, astounded the audio world. He was at the time owner and MD of Lowther. Lowther are the direct descendants of Paul Voight, who first dared to suggest that accurate audio reproduction was possible before WW II. He proved it with his Voight corner horn. Anyhow there was a big musical gathering at St Paul's Cathedral that required reinforcement. The PA experts of the day failed to satisfy. Donald Chave filled the space with four six inch full range drivers! Comments on the event were full of praise for the sound reinforcement.

Now at my old home parish Church there has been a chronic problem of intelligibility of speech. It is 60s building with a a roof line that has a low arch line in front of the altar, and raises towards the altar and to the back of the church. It is about as wide as it is long. It is a big space. My father who has been footing the bills called a halt. I made some suggestions which he didn't like. So he bought a couple of Lowther PM 6 six inch drivers. He built front loading horns for them. How? They looked about right to him! He had them hung up either side of the low point of the arch just where the ceiling fans up towards the rear of the church. Well I was shocked. Not only was it a good PA system, but one of the best I ever heard. Speech intelligibility was excellent in a difficult space. Now here is the interesting part. I calculated the horn flares to have a cut off between 150 and 160 HZ. I played some organ and choral CDs through the system. The bass was amazing. The choral sounds excellent. It was a Hi Fi system, and it was never intended to be. I realized that the shape of the church was coupling to the horn mouths and greatly extending the bass response beyond the flare cut off. Now that was all done without any calculation, just intuition. Quite a lesson.
 
3db

3db

Audioholic Overlord
BTW, since this was a 3 way in which you heard this 'distortion', it does not seem likely it could be phase modulation distortion(a.k.a. misnomer Doppler). I think in your example, it was likely good ol' fashioned inter-modulation distortion, a result of an insufficiently steep high pass filter on the mid-range(or even on the tweeter); the mid-range(and tweeter) motor/suspension was probably optimized for extremely low level excursion relative to the bandwidth and filter that was used; and the insufficient filter was allowing too much lower frequency energy, causing the unit(s) to exceed linear motor/suspension range(s).

-Chris
The SB-T200 is/was a 2-way in a d'Apolito array.

http://hometheaterspeaker.alege.net/Technics-SB-T200-Main-Stereo-Speaker.html

What I read about IM in that article you posted (Thanks BTW :) ) is the opposite of what happened. I only noticed the shift in sound as I decreased the volume. It may have happend on the increase but I didn't detect it but I clearly heard the pitch change on lowering of the volume.

If TLS exmaple is correct, I understand what Doppler effect is now on a speaker.
 
WmAx

WmAx

Audioholic Samurai
Chris,
You are dead wrong. That driver is a VERY accurate high fidelity driver.
I'll gladly measure one of these 4" drivers if you want to loan one. If your claims are accurate, it would be the 1st small diamter driver, of any I have come across, and this is compared to multitudes of high quality modern drivers with known state of the art motors, that could produce LF dynamic bass(without being used in a line array) without substantial distortion artifacts.

-Chris
 
TLS Guy

TLS Guy

Audioholic Slumlord
Chris,
You are dead wrong. That driver is a VERY accurate high fidelity driver. It held a strong nitch position for around 25 years. It was especially revered in the Far East, where it still is. There are sites, which I can't decipher, still devoted to this driver. I have used it in times past in big installation as the mid, eight a side. They were used in the remarkable large installation at the military band school Kneller Hall.

I confessed yesterday to be a full ranger at heart, and I'm unrepentant. I recently had a lesson in totally intuitive audio engineering from my 85 year old father. He recalled the time when the late Donald Chave, who we knew well, astounded the audio world. He was at the time owner and MD of Lowther. Lowther are the direct descendants of Paul Voight, who first dared to suggest that accurate audio reproduction was possible before WW II. He proved it with his Voight corner horn. Anyhow there was a big musical gathering at St Paul's Cathedral that required reinforcement. The PA experts of the day failed to satisfy. Donald Chave filled the space with four six inch full range drivers! Comments on the event were full of praise for the sound reinforcement.

Now at my old home parish Church there has been a chronic problem of intelligibility of speech. It is 60s building with a a roof line that has a low arch line in front of the altar, and raises towards the altar and to the back of the church. It is about as wide as it is long. It is a big space. My father who has been footing the bills called a halt. I made some suggestions which he didn't like. So he bought a couple of Lowther PM 6 six inch drivers. He built front loading horns for them. How? They looked about right to him! He had them hung up either side of the low point of the arch just where the ceiling fans up towards the rear of the church. Well I was shocked. Not only was it a good PA system, but one of the best I ever heard. Speech intelligibility was excellent in a difficult space. Now here is the interesting part. I calculated the horn flares to have a cut off between 150 and 160 HZ. I played some organ and choral CDs through the system. The bass was amazing. The choral sounds excellent. It was a Hi Fi system, and it was never intended to be. I realized that the shape of the church was coupling to the horn mouths and greatly extending the bass response beyond the flare cut off. Now that was all done without any calculation, just intuition. Quite a lesson.
By the way some of you will wonder how this possible. Well the db scale. The Lowther PM 6 has a sensitivity of 96db 1 watt at 1 meter. Put two together and you have 102 db. Donald Cave used a total of 60 watts from tube amps. That's all there was then. However that would be equivalent of a little over 1000 watts power with conventional speakers.

In my fathers case 100 watts of amplification was used, which is equivalent to driving conventional speakers with 1000 watts of amplification.
 
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