Hi tech guys
I'm seeking some clarity on correct tuning for 416 Altec woofer (reconed by GPA) in new cabinet.
The internal volume is very close to 170 liters.
Cab is double walled and braced. Approx 80Kgs each.
The port is 300mm x 65mm x 80mm deep.
How can I check the tuning of this with the 416 T/S specs?
Altec Thiele-Small Parameters
MantaRay horn with 291 1.4 inch driver.
BTW, the speakers are sounding FANTASTIC...so this is an exercise in theory/checking only.
Cabs finished in lovely two pack poly, grey, with pearlesc additive.
Xover is 750Hz, with LR2 and quality Jantzen silver caps.
With thanks, Andrew.
I'm seeking some clarity on correct tuning for 416 Altec woofer (reconed by GPA) in new cabinet.
The internal volume is very close to 170 liters.
Cab is double walled and braced. Approx 80Kgs each.
The port is 300mm x 65mm x 80mm deep.
How can I check the tuning of this with the 416 T/S specs?
Altec Thiele-Small Parameters
MantaRay horn with 291 1.4 inch driver.
BTW, the speakers are sounding FANTASTIC...so this is an exercise in theory/checking only.
Cabs finished in lovely two pack poly, grey, with pearlesc additive.
Xover is 750Hz, with LR2 and quality Jantzen silver caps.
With thanks, Andrew.
Attachments
using those figures and George Augspurger's vent routine "ventwrk" i get ~41.6 Hz so ballpark might be around 40 maybe a bit lower. What's the waveguide/horn/driver and crossover ?
you could run an input impedance sweep or if just have a multi - meter, use a series resistor and some sort of pc driven test tone generator and amplifier. A series resistor of 600 to 1K ohms is typical and a 10 ohm resistor can be switched in as a load to read "10 ohms" on the meter at any frequency to make it accurate with the speaker load by adjusting drive level. (some cheap meters aren't accurate at lower and higher F) The impedance minimum between two "humps" will be your tuning.
in this forum "fullrange" usually indicates single driver speakers and no xover
you could run an input impedance sweep or if just have a multi - meter, use a series resistor and some sort of pc driven test tone generator and amplifier. A series resistor of 600 to 1K ohms is typical and a 10 ohm resistor can be switched in as a load to read "10 ohms" on the meter at any frequency to make it accurate with the speaker load by adjusting drive level. (some cheap meters aren't accurate at lower and higher F) The impedance minimum between two "humps" will be your tuning.
in this forum "fullrange" usually indicates single driver speakers and no xover
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Ditto HR.
FYI, vented cabs are Helmholtz resonators, so don't need any driver specs to find just Fb. Of course with driver specs we can see how the cab's tuning has modified the driver's raw response.
GM
Very nice, though surprised such an under damped [prosound] alignment would sound 'fantastic' in a HIFI app unless heavily stuffed, making effective tuning [much] lower to boot. Then again many folks really prefer its artificial mid-bass thump [Freddi
]. Too 'DJ party' sounding to me assuming it's performing as simmed.GM
Thanks GM
I've enjoyed building speakers for a while...and I love the ALtec gear.
This config was to satisfy my need for a 'room friendly' size...hence the dims.
I've listened to/owned multicells, 511, 811, plus others from Azura (340Hz le cleach) and Autotech (Iwata 300), plus my hand made Yuichi 290's.
I think the smaller 564 Mantaray sounds the best of the Altec horns...though I haven't yet listened to a larger multi cell or a larger Mantaray yet.
I wouldn't describe the speakers as 'pro' sounding...but I understand the comment.
I recently built a Model 19 pair, and I can certainly attest to the deeper bass due to 240-250 liter cabinet size. The 811 horns sounded good, but not as balanced as the 564.
So, I'm going to do two things:
- check the driver in cabinet using sine wave and measure
- play around with dampening, as I've followed a Ye Olde Altec rule of applying dampening to three non facing sides.
See pic of Model 19 (ignore the xover, as these were temporary units). Fs of the reconed drivers were 21Hz....and the bass response in the cabinet was excellent. Foam around driver not in that pic.
Andrew
I've enjoyed building speakers for a while...and I love the ALtec gear.
This config was to satisfy my need for a 'room friendly' size...hence the dims.
I've listened to/owned multicells, 511, 811, plus others from Azura (340Hz le cleach) and Autotech (Iwata 300), plus my hand made Yuichi 290's.
I think the smaller 564 Mantaray sounds the best of the Altec horns...though I haven't yet listened to a larger multi cell or a larger Mantaray yet.
I wouldn't describe the speakers as 'pro' sounding...but I understand the comment.
I recently built a Model 19 pair, and I can certainly attest to the deeper bass due to 240-250 liter cabinet size. The 811 horns sounded good, but not as balanced as the 564.
So, I'm going to do two things:
- check the driver in cabinet using sine wave and measure
- play around with dampening, as I've followed a Ye Olde Altec rule of applying dampening to three non facing sides.
See pic of Model 19 (ignore the xover, as these were temporary units). Fs of the reconed drivers were 21Hz....and the bass response in the cabinet was excellent. Foam around driver not in that pic.
Andrew
Attachments
You're welcome!
'Prosound' as it applied during Altec's 'reign'. Today, it's flat out boombox mode mid-bass 'thump', then EQ'd to suit the app = ~100 L/60-65 Hz Fb.
Can't recall ever auditioning the 564, but in theory would be great for small listening areas such as a recording studio and especially if this small audio 'triangle' was set in a much larger space.
Yeah, saw those recently, makes the originals look cheap in comparison, which no doubt are. Regardless, the 19 was a good value at the time if it was what one wanted and had the space to do it justice.
My fave Altec horns were the 1803s till I made conical WGs ~ the same physical dims loaded with an 802-16G and 808-16A with the later rolled off above ~3500 Hz/2nd order.
All time fave I've auditioned is the three way Synergy concept horn.
Regardless, great work as always and thanks for sharing your continuing W.E./Lansing/Altec's speaker design concepts on how best overall to reproduce a sonic event.
GM
'Prosound' as it applied during Altec's 'reign'. Today, it's flat out boombox mode mid-bass 'thump', then EQ'd to suit the app = ~100 L/60-65 Hz Fb.
Can't recall ever auditioning the 564, but in theory would be great for small listening areas such as a recording studio and especially if this small audio 'triangle' was set in a much larger space.
Yeah, saw those recently, makes the originals look cheap in comparison, which no doubt are. Regardless, the 19 was a good value at the time if it was what one wanted and had the space to do it justice.
My fave Altec horns were the 1803s till I made conical WGs ~ the same physical dims loaded with an 802-16G and 808-16A with the later rolled off above ~3500 Hz/2nd order.
All time fave I've auditioned is the three way Synergy concept horn.
Regardless, great work as always and thanks for sharing your continuing W.E./Lansing/Altec's speaker design concepts on how best overall to reproduce a sonic event.
GM
Thanks for your insightful comments, Greg.
I also built a conical horn, approx. 400Hz Fs. I thought it sounded 'OK', but not terrific. See pic. These had two inch throat, and I used a 2:1 inch adapter for 1 inch driver.
I do love the look of conical horns, especially from the likes of OMA.
Here in Oz, Paul from Red Spade is building a great Synergy horn product.
Red Spade Audio PSE-144
I also built a conical horn, approx. 400Hz Fs. I thought it sounded 'OK', but not terrific. See pic. These had two inch throat, and I used a 2:1 inch adapter for 1 inch driver.
I do love the look of conical horns, especially from the likes of OMA.
Here in Oz, Paul from Red Spade is building a great Synergy horn product.
Red Spade Audio PSE-144
Attachments
You're welcome!
Not surprised since a conical either needs a mouth end correction ['flip out'] to keep it from 'waist banding' or XO'd at least a half octave above its full WL axial length of ~34"/400 Hz, which yours appear to be much shorter, so assuming ~800 Hz in length, then around 1200 Hz and of course will need CD horn EQ to flatten it.
When I did it, had no clue about such things as Harry O. made no mention of it, though in retrospect his horns were big enough that cinema sound was so rolled off up high at the time that there wasn't enough HF BW to 'waist band'. No longer have the book, so don't know if this was somehow implied and I just missed it in my then near total ignorance.
Regardless, I could sure hear it, so having already begun my odyssey of using various materials to damp the various consumer/prosound horn's horrible mouth reflections back to the throat, added an open cell foam horn extension to them, making me a conical horn convert for any serious HIFI app, so might want to try it and d**n the WAF before giving up on so much fine woodworking. Typically I made them at least an octave larger than the design cutoff or 200 Hz in your case, i.e. extend the mouth till its diameter is ~22".
GM
Not surprised since a conical either needs a mouth end correction ['flip out'] to keep it from 'waist banding' or XO'd at least a half octave above its full WL axial length of ~34"/400 Hz, which yours appear to be much shorter, so assuming ~800 Hz in length, then around 1200 Hz and of course will need CD horn EQ to flatten it.
When I did it, had no clue about such things as Harry O. made no mention of it, though in retrospect his horns were big enough that cinema sound was so rolled off up high at the time that there wasn't enough HF BW to 'waist band'. No longer have the book, so don't know if this was somehow implied and I just missed it in my then near total ignorance.
Regardless, I could sure hear it, so having already begun my odyssey of using various materials to damp the various consumer/prosound horn's horrible mouth reflections back to the throat, added an open cell foam horn extension to them, making me a conical horn convert for any serious HIFI app, so might want to try it and d**n the WAF before giving up on so much fine woodworking. Typically I made them at least an octave larger than the design cutoff or 200 Hz in your case, i.e. extend the mouth till its diameter is ~22".
GM
OK, thanks again GM. Having foam extensions would certainly look the part! I guess this is similar in concept to the foam surround on the Model 19 horn.
The larger conical horns, which I think look fantastic, are the Oswald Mills....I'm guessing the wood horns are around 400Hz and 200Hz.
The larger conical horns, which I think look fantastic, are the Oswald Mills....I'm guessing the wood horns are around 400Hz and 200Hz.
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You're welcome!
Correct, though more cosmetic than functional if my then youthful hearing wasn't playing tricks on me later as the first pair of M19s I auditioned were the sales rep's pair with thick yellow fiberglass insulation with a 'dusting' of flat black paint like the Santiago, Valencia had at the time.........which just gave me a thought.......... these wooden horns are thick and obviously not folded back, so yes I meant just wrapped around the outside, but please also test with them tacked into the inside also.........and the more I think about it, wondering if an absorbent phase plug/disc suspended in the mouth [half in, half out] might be a better solution to the tacky looking extension.
The horns I did all had sufficiently flared lips that just making flat pieces that stood proud ~3/4" worked good enough for our ears, though later added some light stuffing in the throats also before deeming them 'good enough'.
GM
