in my neighborhood (like that term BTW);
This is called a second order harmonic or just a second harmonic.
Long version (cut & past from a friend):
So, for anyone interested in the subject, here's a little bit on the ins and outs of distortions.
It really only scratches the surface, because it says little about how or why harmonic distortions are created, and only applies to harmonic distortions and IM distortions created in amplification stages, but it does explain how they affect the sound your ears hear. Here it is:
Any and all distortions most definitely do represent some type of anomalous departure from the original, virgin signal.
Nevertheless, the statement "lowest distortion sounds best" is a half-truth, which mass-market audio companies have propagated since the 1950s.
The general claim is that the lower the distortion, the more faithful to the original signal it will be, therefore the measured THD specs on paper tell you everything about how it'll sound.
In reality, the THD spec tells you just about nothing about how it'll sound.
This is because different distortions are not equal, not even harmonic distortions.
This concept was addressed in the 1950s by the great Norman Crowhurst (and a few others), one of the finest writers of all time on the subject of high quality audio.
It was widely rejected by the engineering community, who put their faith in specs on paper and nothing else. But, those who prefer listening to music over worshipping test equipment know something the "oscilloscope jockeys" don't...
The rudiments of this will be much easier to comprehend if you have some basic knowledge of music theory. By the way, much of the remaining text here is from the rough draft of a paper on distortion that I've been working on.
When a tube (or transistor) achieves its maximum output, it is said to be "saturated."
No matter how much more input signal voltage is fed into it; the output amplitude (voltage swing) cannot increase any further. So, while the main "body" of the output sinewave form does grow and "fatten," its peaks cannot increase any more. On an oscilloscope screen, the normally rounded sinewave peaks appear to be "clipped" off flat, henceforth the condition is known as clipping.
If and when enough drive voltage is fed into the device, the output waveform will eventually become a square wave.
A sinewave is a pure fundamental note, and contains no harmonics.
But, when clipped, harmonics of the fundamental note are created.
These harmonics are musically related to the fundamental frequency, just as the harmonics of a vibrating musical instrument string are musically related to the note's fundamental frequency.
SET amplifiers by nature produce a characteristic asymmetrical sinewave form, even before reaching clipping, which creates a harmonic that is exactly one octave above the fundamental tone.
This is called a second order harmonic or just a second harmonic.
Because it's exactly an octave above the fundamental, it's perceived as adding weight and liquidity to the sound. Imagine hitting the middle C on a piano and the C above it simultaneously. There you have it!
Now, as the tube nears saturation and clipping, higher order harmonics are introduced.
The 3rd harmonic is a musical fifth occurring in the octave above the fundamental.
In the key of C, this would be the G note above the octave C 2nd harmonic tone.
This is still not too terribly dissonant, because the fundamental and fifth harmonize together in a non-dissonant manner.
However, excessive 3rd harmonic does introduce an edginess and a sibilance to the music that is often mistaken by the ear as increased resolution of fine details.
However, what it really does is obscure such microdetails, and increase listening fatigue.
Everyone is familiar with this "fundamental plus fifth" sound, whether they know it or not.
The first and fifth tones of the major scale played together form a double stop (a two-note chord, so to speak; a "true" chord proper has 3 or more notes) that is known as a "power chord" when played on the guitar. It's the characteristic, heavy guitar chord sound that rock music is based upon.
However, in our example, we're using a pure sinewave, not real music.
Real music contains many fundamentals and countless harmonics all happening at the same time, and when you simultaneously superimpose a musical fifth above every single one of them, the sounds becomes much more dissonant than when just a pure 2nd harmonic was present.
The next octave of distortion products (the third octave) is truly "where the rubber meets the road," as the old saying goes.
First of all, let's consider that the 8th harmonic, which is four octaves above the fundamental, occurs on the final note of the third octave.
Therefore the third octave contains the 4th, 5th, 6th, 7th, and 8th harmonics! What a mess!
The 4th harmonic is two octaves above the fundamental, so it's basically an octave of the 2nd harmonic and therefore "in tune," but has a profound "hard-edged" effect on the tonality of the sound in even small amounts, especially when significant 3rd harmonic is also present.
The 5th harmonic is the musical third above that, which would be an E note. This is where we really begin getting into the dissonant stuff.
So far, we have three octaves of the fundamental tone, a third, and a fifth, which together form a well-harmonized major chord triad, or rather a specific inversion of it.
But again, most of us prefer to listen to music instead of sinewaves, and when each individual tone and harmonic present in the music is simultaneously distorted into major chords, the result is total YUCK! Thus, these higher order distortion products sound bad when present with real music, even though they are musically related to the fundamental in a pleasing way.
Moving on higher, the 6th harmonic is an octave above the 3rd harmonic.
The 7th harmonic is a flatted seventh above the 4th harmonic, which in the key of C would be B flat.
On through the 10th harmonic, the harmonics are repeats of the same sequence.
Above the 10th harmonic, things begin to really get freaky.
The 11th harmonic is a flatted fourth (which would be F#), 13th harmonic is a flatted fifth (G#)!
The 12th harmonic between them is another octave of the 3rd harmonic, which would be a G note.
Since the C major scale contains no sharps or flats, the fact that the 11th and 13th harmonics are sharps/flats readily indicates their severely dissonant characteristics.
Two things are realized here.
One, even order distortions are generally less dissonant than odd orders.
High order distortions are more dissonant that low order ones, because they stray farther and farther away from the fundamental note.
Therefore, one can see how significant amounts of low order harmonics (especially 2nd order) are much less objectionable to the ear than even very tiny amounts of high order distortions.
cont'
This is called a second order harmonic or just a second harmonic.
Long version (cut & past from a friend):
So, for anyone interested in the subject, here's a little bit on the ins and outs of distortions.
It really only scratches the surface, because it says little about how or why harmonic distortions are created, and only applies to harmonic distortions and IM distortions created in amplification stages, but it does explain how they affect the sound your ears hear. Here it is:
Any and all distortions most definitely do represent some type of anomalous departure from the original, virgin signal.
Nevertheless, the statement "lowest distortion sounds best" is a half-truth, which mass-market audio companies have propagated since the 1950s.
The general claim is that the lower the distortion, the more faithful to the original signal it will be, therefore the measured THD specs on paper tell you everything about how it'll sound.
In reality, the THD spec tells you just about nothing about how it'll sound.
This is because different distortions are not equal, not even harmonic distortions.
This concept was addressed in the 1950s by the great Norman Crowhurst (and a few others), one of the finest writers of all time on the subject of high quality audio.
It was widely rejected by the engineering community, who put their faith in specs on paper and nothing else. But, those who prefer listening to music over worshipping test equipment know something the "oscilloscope jockeys" don't...
The rudiments of this will be much easier to comprehend if you have some basic knowledge of music theory. By the way, much of the remaining text here is from the rough draft of a paper on distortion that I've been working on.
When a tube (or transistor) achieves its maximum output, it is said to be "saturated."
No matter how much more input signal voltage is fed into it; the output amplitude (voltage swing) cannot increase any further. So, while the main "body" of the output sinewave form does grow and "fatten," its peaks cannot increase any more. On an oscilloscope screen, the normally rounded sinewave peaks appear to be "clipped" off flat, henceforth the condition is known as clipping.
If and when enough drive voltage is fed into the device, the output waveform will eventually become a square wave.
A sinewave is a pure fundamental note, and contains no harmonics.
But, when clipped, harmonics of the fundamental note are created.
These harmonics are musically related to the fundamental frequency, just as the harmonics of a vibrating musical instrument string are musically related to the note's fundamental frequency.
SET amplifiers by nature produce a characteristic asymmetrical sinewave form, even before reaching clipping, which creates a harmonic that is exactly one octave above the fundamental tone.
This is called a second order harmonic or just a second harmonic.
Because it's exactly an octave above the fundamental, it's perceived as adding weight and liquidity to the sound. Imagine hitting the middle C on a piano and the C above it simultaneously. There you have it!
Now, as the tube nears saturation and clipping, higher order harmonics are introduced.
The 3rd harmonic is a musical fifth occurring in the octave above the fundamental.
In the key of C, this would be the G note above the octave C 2nd harmonic tone.
This is still not too terribly dissonant, because the fundamental and fifth harmonize together in a non-dissonant manner.
However, excessive 3rd harmonic does introduce an edginess and a sibilance to the music that is often mistaken by the ear as increased resolution of fine details.
However, what it really does is obscure such microdetails, and increase listening fatigue.
Everyone is familiar with this "fundamental plus fifth" sound, whether they know it or not.
The first and fifth tones of the major scale played together form a double stop (a two-note chord, so to speak; a "true" chord proper has 3 or more notes) that is known as a "power chord" when played on the guitar. It's the characteristic, heavy guitar chord sound that rock music is based upon.
However, in our example, we're using a pure sinewave, not real music.
Real music contains many fundamentals and countless harmonics all happening at the same time, and when you simultaneously superimpose a musical fifth above every single one of them, the sounds becomes much more dissonant than when just a pure 2nd harmonic was present.
The next octave of distortion products (the third octave) is truly "where the rubber meets the road," as the old saying goes.
First of all, let's consider that the 8th harmonic, which is four octaves above the fundamental, occurs on the final note of the third octave.
Therefore the third octave contains the 4th, 5th, 6th, 7th, and 8th harmonics! What a mess!
The 4th harmonic is two octaves above the fundamental, so it's basically an octave of the 2nd harmonic and therefore "in tune," but has a profound "hard-edged" effect on the tonality of the sound in even small amounts, especially when significant 3rd harmonic is also present.
The 5th harmonic is the musical third above that, which would be an E note. This is where we really begin getting into the dissonant stuff.
So far, we have three octaves of the fundamental tone, a third, and a fifth, which together form a well-harmonized major chord triad, or rather a specific inversion of it.
But again, most of us prefer to listen to music instead of sinewaves, and when each individual tone and harmonic present in the music is simultaneously distorted into major chords, the result is total YUCK! Thus, these higher order distortion products sound bad when present with real music, even though they are musically related to the fundamental in a pleasing way.
Moving on higher, the 6th harmonic is an octave above the 3rd harmonic.
The 7th harmonic is a flatted seventh above the 4th harmonic, which in the key of C would be B flat.
On through the 10th harmonic, the harmonics are repeats of the same sequence.
Above the 10th harmonic, things begin to really get freaky.
The 11th harmonic is a flatted fourth (which would be F#), 13th harmonic is a flatted fifth (G#)!
The 12th harmonic between them is another octave of the 3rd harmonic, which would be a G note.
Since the C major scale contains no sharps or flats, the fact that the 11th and 13th harmonics are sharps/flats readily indicates their severely dissonant characteristics.
Two things are realized here.
One, even order distortions are generally less dissonant than odd orders.
High order distortions are more dissonant that low order ones, because they stray farther and farther away from the fundamental note.
Therefore, one can see how significant amounts of low order harmonics (especially 2nd order) are much less objectionable to the ear than even very tiny amounts of high order distortions.
cont'
Now, let's look at how this applies to real world amplifiers.
A typical, well designed SET amp at normal listening levels on very efficient speakers may have around 2 or 3% 2nd harmonic, with very small amounts of 3rd harmonic and almost nonexistent higher harmonics. A push pull amplifier using copious NFB may only have .1% THD, but that .1% distortion consists of a great deal of high order harmonics.
Ditto for most solid state, which may have even much lower THD, but what is present is extremely offensive sounding, high order harmonics.
This illustrates that THD specs on paper mean absolutely nothing.
Additionally, very few people understand how "on-paper" distortion percentages correlate to the ear's actual perception of them.
If you run an amplifier on a harmonic distortion analyzer, and it tells you there is 1% THD, does that mean there's really 1% THD? Well, yes and no.
The analyzer measures the distortion as a voltage that makes up a certain percentage of the main signal voltage, not its actual sonic perception. Or, as I like to put it, "Computers ain't got ears. People do." However, some simple math can provide a relative conversion from volts to perceived sound pressure level.
The HD analyzer tells us that we have 1% THD, which is 40dB below the fundamental. Converting -40dB to wattage would be 1/10,000 of the full power, which with a 10 watt amp would be 1 milliwatt. These wattage/percentage figures of course have no relation to how they will be perceived by actual human ears. Now, here's where we get down to the nitty gritty...
The ear does not perceive volume in a linear manner, but on a logarithmic curve. To net a doubling of perceived volume (approximately equal to 10dB) requires 10 times the power; likewise a halving of the volume requires cutting the power by 10 times. So, -40dB represents an actual 16:1 ratio to the ear's perception, not a 10,000:1 ratio, because the ear perceives that -10dB would be half the volume, -20 one-fourth the volume, -30dB one-eighth the volume, and -40dB one-sixteenth the volume.
OK, let's see what 1% measured THD really sounds like to the ear.
100% ÷ 16 = 6.25%
This illustrates how the ear can very easily pick out tiny percentages of high order harmonics.
Consider a nasty high order harmonic that's buried -80dB down.
To the ear, a 7th harmonic at -80dB sounds like 3.1% 7th order distortion, very offensive indeed!
Add all the other harmonics from 3rd through 6th with it, and you've got yourself a real mess.
Finally, if things weren't already bad enough, we have a lot more than harmonic distortions to contend with. We have non-harmonic distortions too! Any time you put two sinewaves together, you create two new frequencies, the sum of the two and the difference between them.
These are, not surprisingly, called the quadratic sum and difference frequencies. (or ring modulation)
Most of the time, the resulting intermodulations are musically unrelated to the original frequencies and therefore horribly dissonant.
Let's use a 440Hz sinewave as an example, which is the tuning standard for musical instruments.
It is equivalent to the open A string of the violin, the A note above middle C on the piano, and is two octaves above the open A string of the guitar.
If we added a 880Hz sinewave with it, we'd have the original 440Hz and 880Hz frequencies, plus the sum frequency of 1.32kHz and the difference frequency of 440Hz. 1.32kHz is almost exactly an E note, which would be a musical fifth above the 880Hz note and would be equivalent to the 3rd harmonic of the 440Hz note. Not just too terrible...
Interestingly, if we superimpose that 1.32kHz E note sinewave over the 440Hz A note, we'll get:
440Hz + 1.32kHz = 1.76kHz
1.32kHz - 440Hz = 880Hz
Notice that 1.76kHz is exactly one octave above 880Hz, which is one octave above our original A-440 note. Therefore, we still have A notes and an E note. However, this is only one of many intermodulation frequencies occurring in music during any given split-second.
This illustrates how low order harmonically related tones intermodulate to form harmonically related tones of similar nature. Now, let's move on to a higher order, harmonically related tone, intermodulate it with our A-440 note, and see what comes out.
Let's use a musical third, that's in the third octave above the fundamental.
This would be a C# note, which would correlate to a 5th order harmonic relative to the A-440 fundamental.
440Hz + 2.217kHz = 2.657kHz
2.217kHz - 440Hz = 1.777kHz
The resulting intermodulation frequencies are musically unrelated to both the original tones.
The sum frequency falls between E and F in pitch, and F is not within the A major scale anyway.
The difference frequency is 17Hz sharper than the nearest actual note (an A note), so that it sounds like two musicians playing the same piece together but with their instruments badly out of tune with each other, which makes for a rather hair-raising discordance.
From this, you can see two things.
One, the more frequencies that are simultaneously present, the more intermodulation distortions you'll have.
Two, high order harmonics give way to some very dissonant intermodulations.
Guitar players who play distorted styles are intimately familiar with intermodulation distortions, regardless of whether they've ever heard the term or not!
A guitar amplifier with lots of very high order harmonics will typically also have very high intermodulation distortion.
A single note played on such an amplifier will have decent definition and clarity, but when a chord is played, you get a harsh, homogenized goo with no clarity or definition of the individual notes within the chord.
However, due to design flaws within the amplifier itself, it is also possible to have very high IM distortion while having rather low THD, which makes it impossible to get a good, clear, chimey sound, even when a very mild, light overdrive is dialed in.
IM distortions are a chief reason why many guitar amplifiers sound harsh and congested, and why many hi-fi amps sound homogenized when playing complex passages.
Eddie
A typical, well designed SET amp at normal listening levels on very efficient speakers may have around 2 or 3% 2nd harmonic, with very small amounts of 3rd harmonic and almost nonexistent higher harmonics. A push pull amplifier using copious NFB may only have .1% THD, but that .1% distortion consists of a great deal of high order harmonics.
Ditto for most solid state, which may have even much lower THD, but what is present is extremely offensive sounding, high order harmonics.
This illustrates that THD specs on paper mean absolutely nothing.
Additionally, very few people understand how "on-paper" distortion percentages correlate to the ear's actual perception of them.
If you run an amplifier on a harmonic distortion analyzer, and it tells you there is 1% THD, does that mean there's really 1% THD? Well, yes and no.
The analyzer measures the distortion as a voltage that makes up a certain percentage of the main signal voltage, not its actual sonic perception. Or, as I like to put it, "Computers ain't got ears. People do." However, some simple math can provide a relative conversion from volts to perceived sound pressure level.
The HD analyzer tells us that we have 1% THD, which is 40dB below the fundamental. Converting -40dB to wattage would be 1/10,000 of the full power, which with a 10 watt amp would be 1 milliwatt. These wattage/percentage figures of course have no relation to how they will be perceived by actual human ears. Now, here's where we get down to the nitty gritty...
The ear does not perceive volume in a linear manner, but on a logarithmic curve. To net a doubling of perceived volume (approximately equal to 10dB) requires 10 times the power; likewise a halving of the volume requires cutting the power by 10 times. So, -40dB represents an actual 16:1 ratio to the ear's perception, not a 10,000:1 ratio, because the ear perceives that -10dB would be half the volume, -20 one-fourth the volume, -30dB one-eighth the volume, and -40dB one-sixteenth the volume.
OK, let's see what 1% measured THD really sounds like to the ear.
100% ÷ 16 = 6.25%
This illustrates how the ear can very easily pick out tiny percentages of high order harmonics.
Consider a nasty high order harmonic that's buried -80dB down.
To the ear, a 7th harmonic at -80dB sounds like 3.1% 7th order distortion, very offensive indeed!
Add all the other harmonics from 3rd through 6th with it, and you've got yourself a real mess.
Finally, if things weren't already bad enough, we have a lot more than harmonic distortions to contend with. We have non-harmonic distortions too! Any time you put two sinewaves together, you create two new frequencies, the sum of the two and the difference between them.
These are, not surprisingly, called the quadratic sum and difference frequencies. (or ring modulation)
Most of the time, the resulting intermodulations are musically unrelated to the original frequencies and therefore horribly dissonant.
Let's use a 440Hz sinewave as an example, which is the tuning standard for musical instruments.
It is equivalent to the open A string of the violin, the A note above middle C on the piano, and is two octaves above the open A string of the guitar.
If we added a 880Hz sinewave with it, we'd have the original 440Hz and 880Hz frequencies, plus the sum frequency of 1.32kHz and the difference frequency of 440Hz. 1.32kHz is almost exactly an E note, which would be a musical fifth above the 880Hz note and would be equivalent to the 3rd harmonic of the 440Hz note. Not just too terrible...
Interestingly, if we superimpose that 1.32kHz E note sinewave over the 440Hz A note, we'll get:
440Hz + 1.32kHz = 1.76kHz
1.32kHz - 440Hz = 880Hz
Notice that 1.76kHz is exactly one octave above 880Hz, which is one octave above our original A-440 note. Therefore, we still have A notes and an E note. However, this is only one of many intermodulation frequencies occurring in music during any given split-second.
This illustrates how low order harmonically related tones intermodulate to form harmonically related tones of similar nature. Now, let's move on to a higher order, harmonically related tone, intermodulate it with our A-440 note, and see what comes out.
Let's use a musical third, that's in the third octave above the fundamental.
This would be a C# note, which would correlate to a 5th order harmonic relative to the A-440 fundamental.
440Hz + 2.217kHz = 2.657kHz
2.217kHz - 440Hz = 1.777kHz
The resulting intermodulation frequencies are musically unrelated to both the original tones.
The sum frequency falls between E and F in pitch, and F is not within the A major scale anyway.
The difference frequency is 17Hz sharper than the nearest actual note (an A note), so that it sounds like two musicians playing the same piece together but with their instruments badly out of tune with each other, which makes for a rather hair-raising discordance.
From this, you can see two things.
One, the more frequencies that are simultaneously present, the more intermodulation distortions you'll have.
Two, high order harmonics give way to some very dissonant intermodulations.
Guitar players who play distorted styles are intimately familiar with intermodulation distortions, regardless of whether they've ever heard the term or not!
A guitar amplifier with lots of very high order harmonics will typically also have very high intermodulation distortion.
A single note played on such an amplifier will have decent definition and clarity, but when a chord is played, you get a harsh, homogenized goo with no clarity or definition of the individual notes within the chord.
However, due to design flaws within the amplifier itself, it is also possible to have very high IM distortion while having rather low THD, which makes it impossible to get a good, clear, chimey sound, even when a very mild, light overdrive is dialed in.
IM distortions are a chief reason why many guitar amplifiers sound harsh and congested, and why many hi-fi amps sound homogenized when playing complex passages.
Eddie
el`Ol said:
For those who've actually had a chance to hear these drivers - presumably "stock" and likely at the early stages of their break-in cycle - how problematic are these issues?
I've heard phase-plugs provide significant improvements as well as mixed blessings to Fostex FE series drivers, and for one would be more inclined to try treating the dustcap on such a rare and costly driver before cutting it off.
Your friend is what a friend of mine calls a "good splainer". Thanks for posting this.
Regards.
Aengus
Aengus said:
y'all should hear his amps, Aengus - actually you can if you give Frank McCrea a call
Eddie is definitely a gem - just don't get stuck in a phone call
Hi guys,
Oops, and I made the issue even more confusing by calling the "first overtone" the "first harmonic" but I should have said "first overtone" == second harmonic. Robert, wow, that was a fascinating read.
Oops, and I made the issue even more confusing by calling the "first overtone" the "first harmonic" but I should have said "first overtone" == second harmonic. Robert, wow, that was a fascinating read.
chrisb,
I don't know "how problematic" I'd describe it...
Noticable, it bugs me for as much as the things cost...
I was thinking the same thing about dotting the dust cap.
It's pretty deep drawn for being mag.
I don't really want to mod anything until I get quite a few more hours on them though, as I do know some Fostex change quite a bit with time.
The 108ESr-IIs changed a lot after a few hundred hours...
Aengus, rjbond3rd,
Yeah, great splainer, & what chrisb said about his amps.
I've built three based on his schematics & splainin' that are some of the best amps I've ever heard.
One of those people that amazes me most every time I talk to him.
I don't know "how problematic" I'd describe it...
Noticable, it bugs me for as much as the things cost...
I was thinking the same thing about dotting the dust cap.
It's pretty deep drawn for being mag.
I don't really want to mod anything until I get quite a few more hours on them though, as I do know some Fostex change quite a bit with time.
The 108ESr-IIs changed a lot after a few hundred hours...
Aengus, rjbond3rd,
Yeah, great splainer, & what chrisb said about his amps.
I've built three based on his schematics & splainin' that are some of the best amps I've ever heard.
One of those people that amazes me most every time I talk to him.
Fe 138 ES-r
Hello,
the driver is tested in Hobby HiFi DEZ/JAN. 2009,
it was not easy to write positiv about it,
i think,
needs notch filter, a bass horn up to
~400 Hz (impossible), and from 4 kHz HT suck outs ~10 dB,
no bad the Xmax ~ 13 mm,
very good Rms 0,28.
Is this a hipe to make money,
in europa they will sell only 50 drivers.
Hello,
the driver is tested in Hobby HiFi DEZ/JAN. 2009,
it was not easy to write positiv about it,
i think,
needs notch filter, a bass horn up to
~400 Hz (impossible), and from 4 kHz HT suck outs ~10 dB,
no bad the Xmax ~ 13 mm,
very good Rms 0,28.
Is this a hipe to make money,
in europa they will sell only 50 drivers.
Actually, thai is one of the ways I've been thinking about using it-
With a Tapped horn on the very bottom,
then a mid bass horn up to ~ 400Hz,
In a LeCleach FLH,
Then something for a super-tweeter.
Any details of what they recommended for a filter?
Just around 5K?
or starting around 1?
Not at all what I had in mind when I bought it though...
Getting complicted...
I wanted something simple, to use as a full-range, or wide-range w/ sub...
Something like a poor man's Feastrex, (hearing the Nessies @ RMAF inspired me, they were real nice if kept in bounds FR wise, dynamics wise, and low enough SPL).
r
With a Tapped horn on the very bottom,
then a mid bass horn up to ~ 400Hz,
In a LeCleach FLH,
Then something for a super-tweeter.
Any details of what they recommended for a filter?
Just around 5K?
or starting around 1?
Not at all what I had in mind when I bought it though...
Getting complicted...
I wanted something simple, to use as a full-range, or wide-range w/ sub...
Something like a poor man's Feastrex, (hearing the Nessies @ RMAF inspired me, they were real nice if kept in bounds FR wise, dynamics wise, and low enough SPL).
r
i had been thinking of something along the lines of a "beauhorn virtuosso" design for the 138esr.
Hi Robert, would you make your own LeCleach FLH's, and if so, what technique would you use to shape/build them?
Ahh, the big BLH plan.mp9 said:
That's what I did with my 166ES-Rs, studied the above, Carfrae Horns, Lowther TP-1s, & ended up building Ron Clark's Austin 166s-- they seem as well designed as any of the others.
Might be a good choice.
In general I like them.
Work best corner loaded with a a sub built into the rear deflector & a super tweeter (~15K).
138 would probably work well BLH too...
I'm just kinda turned off by the time delay you can hear on some material caused by the long path off the back of the driver vs the short path off the front of the driver.
Don't always notice it, but it makes some music just "out of time."
No more BLHs for me.
That's what I'm afraid a Nessie would do too, even though the inside path isn't quite as long.
And why I was thinking Scott's BVR might be better.
Wish someone would post freq response graphs...
r
rjbond3rd,
yeah, i like to diy everything.
I built 250 Hz LeCleach paper ones, (actually works very well, hard outside, soft inside, very well damped, sounds nice) testing the 2" drivers for a five-way FLH horn system I'm building.
Gonna build soft & hard wood ones to compare sound.
I cut the throat, added cardboard adaptor just to get general idea with the 138, haven't computed back chamber, or sealed it properly.
Therefore wasn't anything I'd call conclusive, but (as expected) sounded nicer in narrower band, mids up.
I haven't put a lot of thought in it, but it might sound nice with the horn being an acoustic band-pass ~400/500 - 10K?
yeah, i like to diy everything.
I built 250 Hz LeCleach paper ones, (actually works very well, hard outside, soft inside, very well damped, sounds nice) testing the 2" drivers for a five-way FLH horn system I'm building.
Gonna build soft & hard wood ones to compare sound.
I cut the throat, added cardboard adaptor just to get general idea with the 138, haven't computed back chamber, or sealed it properly.
Therefore wasn't anything I'd call conclusive, but (as expected) sounded nicer in narrower band, mids up.
I haven't put a lot of thought in it, but it might sound nice with the horn being an acoustic band-pass ~400/500 - 10K?
Hi Robert, yowza! Did you machine a mold first, and then you put layers of paper and adhesive over the mold?
Oh good news -- a warm, caring family is available to adopt your Austins, and the best part is that you can visit them as often as you like. 🙂
Oh good news -- a warm, caring family is available to adopt your Austins, and the best part is that you can visit them as often as you like. 🙂
serenechaos said:
I think Scott explained why he considered the "modeled response" graphics as counter-productive for many, but of course, not all potential builders.
To which add my personal observation - any full spectrum "real world" measurements will of course be only real for the exact "world" in which they were made.
I have 3 systems in my home, each with distinctly different properties and goals , and none are anechoic or virtual environments. I'd be (temporarily) interested in software sophisticated enough to predict exactly what any proposed system would sound like in any of these spaces. No, actually, I lied - I'd rather simply try them for myself.
scott,
i don't understand.
sorry if i said something to offend...
i keep looking for what your comments are in context to, all i can find is that you posted a curve in Post #258, and commented in Post #262...
But that was on using a FLH...
I just wanted a general idea or where roll-off was, and a general idea of where to expect F3 to be, (I'm not going to be using these in any where near "perfect" room, etc.)...
Do have plans for a small TH that's ~95dB 20 - 60 Hz in 1 Pi & was wondering if the two might work well together...
Seeing the roll-off of the BVR lines up with the TH so well, it kinda makes that more worth trying to me.
no comments, but thanx!
i don't understand.
sorry if i said something to offend...
i keep looking for what your comments are in context to, all i can find is that you posted a curve in Post #258, and commented in Post #262...
But that was on using a FLH...
I just wanted a general idea or where roll-off was, and a general idea of where to expect F3 to be, (I'm not going to be using these in any where near "perfect" room, etc.)...
Do have plans for a small TH that's ~95dB 20 - 60 Hz in 1 Pi & was wondering if the two might work well together...
Seeing the roll-off of the BVR lines up with the TH so well, it kinda makes that more worth trying to me.
no comments, but thanx!
No offense taken mate -there's nothing here that's personal to you; I was speaking generally.
For the sake of interest, I stopped posting computer models for anything but the more basic designs like MLTLs, BRs & the like a little while ago (not just here), because they were proving to be a double-edged sword. While they're very useful to the designer, they are often less so to the end user, because what you see isn't really what you get. For a start, they're 1/2 space graphs, so in-room behaviour is very different. It's also a case of needing to know both what a design does / is for, and also what the software does & doesn't show. For e.g., the (soon to be replaced) Olivia box on the FH site sims max-flat in 1/2 space to 50Hz, but in practice, it won't go anything like that low. It wasn't actually intended to -that just happens to be how it models, but the graph may unintentionally mislead some people. There were a couple of other, less important matters too, but it was primarily for this reason that I've quit posting graphs for the time being. I might start again at some point in the future, but for now, I prefer not to.
FWIW, in practice, expect an F3 around 60Hz.
For the sake of interest, I stopped posting computer models for anything but the more basic designs like MLTLs, BRs & the like a little while ago (not just here), because they were proving to be a double-edged sword. While they're very useful to the designer, they are often less so to the end user, because what you see isn't really what you get. For a start, they're 1/2 space graphs, so in-room behaviour is very different. It's also a case of needing to know both what a design does / is for, and also what the software does & doesn't show. For e.g., the (soon to be replaced) Olivia box on the FH site sims max-flat in 1/2 space to 50Hz, but in practice, it won't go anything like that low. It wasn't actually intended to -that just happens to be how it models, but the graph may unintentionally mislead some people. There were a couple of other, less important matters too, but it was primarily for this reason that I've quit posting graphs for the time being. I might start again at some point in the future, but for now, I prefer not to.
FWIW, in practice, expect an F3 around 60Hz.
Thanx again!Scottmoose said:
That should mate nicely with that Tapped Horn.
Not quite as simple as I'd hoped (one box, one amp), but should be able to get by with just one amp.
Then mess with the 10 dB "suck out" & peaks on top...
Should have paid more attention before I bought it.
You'd think I would have, as much as the things cost...
r
TL
I tried a few cab designs with fe138esr the TL is very good but large. FE138ESR in this big TL doesn't suffer so from the problems many think fe138esr would based on specs and Sims. Madisound sold me the 1st pair months before they stocked or listed for sale I have spent some time with fe138esr it can sound great. But it needs proper cab. Works great as a wide band midrange too.
I tried a few cab designs with fe138esr the TL is very good but large. FE138ESR in this big TL doesn't suffer so from the problems many think fe138esr would based on specs and Sims. Madisound sold me the 1st pair months before they stocked or listed for sale I have spent some time with fe138esr it can sound great. But it needs proper cab. Works great as a wide band midrange too.
