The 1772 handles classic rock just fine -- Steely Dan, Pink Floyd, Led Zeppelin. I don't have anything more modern, nor do I care.
Single driver speakers are single driver speakers. Doppler distortion will occur with the 1772. As long as the overall SPL is kept within reason, I don't mind this distortion. I was listening to Mahler's 1st and it come off OK. Sustained SPL was well below 90dB, though.
Transient response is good for an 8"er. Given the trade off between snap and weight to drums, I'll take weight every time. 8"ers have guts, 4"ers do not.
(I am working on a speaker for the FE127E and by accident did a comparison of the 127 vs 1772. The 127 and great mid's and tops, but it just won't do convincing bass. It doubles like mad below 60Hz. For instance, in "O Fortuna" from Carmina Burana, the tympany notes are low-high, but through the 127, it comes out high-low. The 1772 has better overall balance and I much prefer this sound for a long listening session.)
If you are into loud rock, I doubt that any single driver MLTL will cut it for you. I don't do horns, so....
Bob
Perceived Speed, Detail and HF Extension
Bob,
The smaller full range drivers are frequently described as having a perceived sound that has greater speed, detail and HF extension than larger drivers. Is this impression true or is it due to the greater LF extension (of the larger drivers), so that as we add more LF extension the perception is of a slower sound with less detail?
Bass extension and character may well affect perceived speed, detail and HF extension, but surely do not alter the drivers transient response and HF extension (provided that the signal does not contain content in the LF range). IME, in the case of multi-way loudspeakers, where the woofer, mid and HF drivers (and crossovers) remain the same, but the enclosure is changed to produce greater LF extension, the perception is of decreasing detail, speed and HF extension as bass extension increases. An overprominent bass can result is a slow and dull overall sound.
If the perception of speed, detail and HF extension is to some (significant) extent a sound 'balance' issue, then is it possible that a good quality larger full range driver (like the 1772) might in fact have as much speed, detail and HF extension as some smaller drivers (like the 127e)?
Along these same lines, could the greater speed, detail and HF extension of some low Qts full range drivers (like the 206e and most Lowthers) be at least in part due to tilted-up response and a lack of balance? Do these drivers retain their 'speedy' characteristics when frequency contoured and/or loaded by an enclosure to provide a more balanced sound? With both the 1772 and DX-3 frequency contoured and enclosure-loaded for a balanced sound, will the DX-3 sound faster, more detailed and with greater HF extension? I suppose departures from linear frequency response may make such a comparison difficult.
And a little off-topic (but quite related), does the high flux density in the gap impart superior transient response and HF extension relative to otherwise similar mid-Qts drivers or is this to a large extent due to tilted up, out of balance response? Could this phenomen at least partly explain the increasingly greater speed, detail and HF extension heard as one 'progresses' to lower Qts (higher flux density) Lowther drivers (such as from DX-2 to DX-3 to DX-4)? Or does the high flux density impart audibly superior control of the voice coil, but at the expense of an increasingly out of balance frequency response and requiring increasingly more frequency contouring and heroic bass loading efforts?
Regards,
Bob
Bob,
The smaller full range drivers are frequently described as having a perceived sound that has greater speed, detail and HF extension than larger drivers. Is this impression true or is it due to the greater LF extension (of the larger drivers), so that as we add more LF extension the perception is of a slower sound with less detail?
Bass extension and character may well affect perceived speed, detail and HF extension, but surely do not alter the drivers transient response and HF extension (provided that the signal does not contain content in the LF range). IME, in the case of multi-way loudspeakers, where the woofer, mid and HF drivers (and crossovers) remain the same, but the enclosure is changed to produce greater LF extension, the perception is of decreasing detail, speed and HF extension as bass extension increases. An overprominent bass can result is a slow and dull overall sound.
If the perception of speed, detail and HF extension is to some (significant) extent a sound 'balance' issue, then is it possible that a good quality larger full range driver (like the 1772) might in fact have as much speed, detail and HF extension as some smaller drivers (like the 127e)?
Along these same lines, could the greater speed, detail and HF extension of some low Qts full range drivers (like the 206e and most Lowthers) be at least in part due to tilted-up response and a lack of balance? Do these drivers retain their 'speedy' characteristics when frequency contoured and/or loaded by an enclosure to provide a more balanced sound? With both the 1772 and DX-3 frequency contoured and enclosure-loaded for a balanced sound, will the DX-3 sound faster, more detailed and with greater HF extension? I suppose departures from linear frequency response may make such a comparison difficult.
And a little off-topic (but quite related), does the high flux density in the gap impart superior transient response and HF extension relative to otherwise similar mid-Qts drivers or is this to a large extent due to tilted up, out of balance response? Could this phenomen at least partly explain the increasingly greater speed, detail and HF extension heard as one 'progresses' to lower Qts (higher flux density) Lowther drivers (such as from DX-2 to DX-3 to DX-4)? Or does the high flux density impart audibly superior control of the voice coil, but at the expense of an increasingly out of balance frequency response and requiring increasingly more frequency contouring and heroic bass loading efforts?
Regards,
Bob
I will try this driver in short BLH and will try to keep the cone excursion as short as this construction can allow.
I alredy purchased a pair and I hope I'll receive it in a week.
By the way, did T/S parameters changed after the longer burn-in?
Yes, the T/S changed somewhat with break-in as one should expect. The numbers I published where after one hour of 10Hz at Xmax. Either way, you can use the numbers since Qts and Vas change in complementary directions nad produce the same box.
Bob
AstroSonic,
Transient response is directly proportional to BL and inversely proportional to Mms. An 8" driver is going to have a Mms that is the cube of a 4" driver, if the cone material is the same thickness. It is unlikely that the BL of the 8"er is going to be the cube of the 4"er. You will probably never see an 8"er with the same acceleration as a 4"er.
Most full-rangers have a rising response. This is often perceived as "detail" and/or "life". How many times have you heard that EQ'ing out the rising response "takes the life out of a speaker"? EQ'ing out the rising response does absolutely nothing to the transient response, it simply restores balance. Now, if you like to hear a rising response, more power to you. It's your ears and your hobby. Different issue.
I own a pair of DX2's and DX3's. Yes, the DX3 has a stronger rising response than the DX2. This is a result of a larger magnet and hence a larger BL. However, once both drivers are EQ'ed back to something that approximates flat, the DX3 has more detail and "air", because it has a faster transient response.
Bob
Transient response is directly proportional to BL and inversely proportional to Mms. An 8" driver is going to have a Mms that is the cube of a 4" driver, if the cone material is the same thickness. It is unlikely that the BL of the 8"er is going to be the cube of the 4"er. You will probably never see an 8"er with the same acceleration as a 4"er.
Most full-rangers have a rising response. This is often perceived as "detail" and/or "life". How many times have you heard that EQ'ing out the rising response "takes the life out of a speaker"? EQ'ing out the rising response does absolutely nothing to the transient response, it simply restores balance. Now, if you like to hear a rising response, more power to you. It's your ears and your hobby. Different issue.
I own a pair of DX2's and DX3's. Yes, the DX3 has a stronger rising response than the DX2. This is a result of a larger magnet and hence a larger BL. However, once both drivers are EQ'ed back to something that approximates flat, the DX3 has more detail and "air", because it has a faster transient response.
Bob
Thats a common misconception as far as my knowledge goes. Read this: http://www.adireaudio.com/Files/WooferSpeed.pdf
I've read that article and I do not believe it. It implies that a driver made out of steel plate will have the same acceleration as a paper cone. No, Dan's analysis only works if BL and m are constant, which they are not with two wildly different drivers. Now ask yourself, do you really think that the same current will produce the same acceleration in an FE127E and a W8-1772? A further thought: Would that same (change in) current will produce the same wave front?
Bob
Right. Basic laws of physics. I'm ashamed to say I actually bought DW's article when I first read it, primarily on the basis of his formidable reputation & I didn't actually think about the implications for some time. 
When I did a few months later, I decided that it doesn't make any sense at all, except in very specific conditions. A non-audio analogy would be if you stuffed the same size engine & breaks in a small car & a large one (or a light car & a heavy one). All other things being equal, which is going to accelerate / decelerate more quickly for a given input? Granted, I buy that VC inductance can make a difference, but it'll be minor compared to wide variations in the mass / inertia of the moving parts, motor strength &c.
When I did a few months later, I decided that it doesn't make any sense at all, except in very specific conditions. A non-audio analogy would be if you stuffed the same size engine & breaks in a small car & a large one (or a light car & a heavy one). All other things being equal, which is going to accelerate / decelerate more quickly for a given input? Granted, I buy that VC inductance can make a difference, but it'll be minor compared to wide variations in the mass / inertia of the moving parts, motor strength &c.
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Keep the engine in the light car, and put a bigger engine in the heavy car, and you will have the same acceleration...
Then the acceleration of bigger driver should be the same as a smaller driver as long as BL scales with mass. Say you have a small driver with BL 10, and mass of 10g. Then you have a bigger one with a BL of 20, and mass of 20g. Will the smaller driver still accelerate faster?
Mms rather following radius by the power of three might be the result.
Keep the engine in the light car, and put a bigger engine in the heavy car, and you will have the same acceleration...
Quite, and hardly rocket science. The entire point is that you need to maintain the ratio as the weight of the moving parts increases. Problem is, it rarely does, as shown.
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Scott,>Weight is not a good thing. It's simply inefficient engineering.<
If speaker Mms had to corner as well as accelerate/decelerate, quite a few "awesome" juggernaut designs might clog the dustbin.
P.S. I don´t have your current email addy, but need to pester you with a few questions - please contact me at H P H i n d e r at k a b e l m a i l dot d e (leave the spaces out
Bob,
I think we are basically on the same page.
I would just add that many (most?) full range drivers are designed with progressive decoupling, reducing the cone area and mass as frequency increases. As a result, the larger drivers perform far better at detail, speed and HF extension than one might expect.
Another factor (in addition to BL and Mms) affecting speed, detail and HF extension is cone deformation (breakup and resonances). While the voice coil may faithfully follow the waveform, the diaphram may not.
That is the point I was trying to make with the multi-way speaker analogy: as one balances a rising high end with more bass, the perception is of less speed, detail and HF extension (or less 'life'). Same for EQing: the more balanced sound ('even' frequency response instead of a rising trend) is perceived as being less 'speedy'. I think that most people would consider an un-EQed (unbalanced) driver to sound 'faster' even though it is not. The reputation of these drivers as being 'fast' is in part due to their rising high end. To me a rising response is like a high contrast photograph. It may make the detail in the photo more apparent, but it does not add more detail. It is not an accurate reflection of the scene and is generally not pleasant to look at.
Thanks for the Lowther information. I was curious about how much of the perceived speed and definition of the higher flux models was due to their motor strength vs their rising response trend.
I am still curious about how the 1772 compares with the DX-3. The 1772 may not offer the speed and detail of the DX-3, but it likely represents very good value and a useful step up from most of the Fostex drivers.
Regards,
Bob
I think we are basically on the same page.
I would just add that many (most?) full range drivers are designed with progressive decoupling, reducing the cone area and mass as frequency increases. As a result, the larger drivers perform far better at detail, speed and HF extension than one might expect.
Another factor (in addition to BL and Mms) affecting speed, detail and HF extension is cone deformation (breakup and resonances). While the voice coil may faithfully follow the waveform, the diaphram may not.
That is the point I was trying to make with the multi-way speaker analogy: as one balances a rising high end with more bass, the perception is of less speed, detail and HF extension (or less 'life'). Same for EQing: the more balanced sound ('even' frequency response instead of a rising trend) is perceived as being less 'speedy'. I think that most people would consider an un-EQed (unbalanced) driver to sound 'faster' even though it is not. The reputation of these drivers as being 'fast' is in part due to their rising high end. To me a rising response is like a high contrast photograph. It may make the detail in the photo more apparent, but it does not add more detail. It is not an accurate reflection of the scene and is generally not pleasant to look at.
Thanks for the Lowther information. I was curious about how much of the perceived speed and definition of the higher flux models was due to their motor strength vs their rising response trend.
I am still curious about how the 1772 compares with the DX-3. The 1772 may not offer the speed and detail of the DX-3, but it likely represents very good value and a useful step up from most of the Fostex drivers.
Regards,
Bob
Quite the opposite
I know what you mean
and in many cases it really is like you describe
Tho, that doesnt means it has to be "true"
Basicly its because its not working properly
To stay in the engine terminology, its like a 100PS engine that only produce 90PS because of unbalanced adjustment
Too speedy fast sound is mostly due to phase issues, which makes me feel stressed an uncomfortable
But you are absolutely right if you said TOO much bass makes the sound "slow"
Same thing again
Too much bass can also be caused by phase issues
Which makes the bass sound muddy and blurred, and slow
Many will say, wrong box allignment, or driver having wrong specs, or poor construction
It may be so in some cases
But it could just as well be caused by phase issues
So, we are almost on the "same page"
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Yup. But here another problem raises its ugly head: EMF. A strong magnet is the most expensive way to avoid bass, unless you DIY and build enclosures you couldn´t ever dream of finding in any store.
Didnt quite get you here... I once tried horn loading a 3 inch fullranger from some pc speaker I had laying around, and it sounded horrible. Shouting, fatiguing sound.
Good means the good, as in opposite of bad... Driver model is the TB 1772. Horn is the Azura 204. Desired peformance is to load the "low end" (down to cutoff freq) to compensate for the rising response, and maybe some directivity controll. (?)
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Well, yes it should. "Speed" is in the harmonics. If the driver can reproduce more of the music's harmonic series, it will be "faster". High efficiency drivers are so because of their low mass and high BL. HF drivers aught to reproduce more of the harmonic series than a LF driver. Note, however, even a big, heavy high Xmax subwoofer will sound "fast" if it is properly crossed over to a driver that produces the harmonics that the sub cannot.
Bob
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