Hello there.
At my job I have been so lucky as to receive a pair of Tangbang W8-1772 for evaluation purpose.
http://www.tb-speaker.com/detail/1230_04/w8-1772.htm
I must say that they look a million.
Thus far we've only tested them in 16l sealed enclosures, the size based on simulation made in WinISD Pro Alpha.
The treble is well-balanced, neither over-analytical nor absent,
the midrange is still a bit hard, but I think it's just a matter of breaking it in, but there is a good speech-intelligibility. No tendency to shout or being nasal.
Bass is of course lacking, and this is where I need advice from You, since I only have experience with TL's and sealed enclosures for Hi-Fi, and none of these are suitable for this fullrangespeaker ;-)
There are many other ways to make bass, deep'n clean, like horns and various ML and quaterwave-styles, and a lot of You who are a lot more experienced than I to se which design will suit this speaker the best, and help with the math!
My evaluation of the speaker will of course be sent to Tangband, together with descriptions of the enclosures used, since they delivered the speakerunits, but the proprietary rights to any design comming from this forum will of course belong to this forum.
Is there anybody out there..........
who are willing to give a hand?
At my job I have been so lucky as to receive a pair of Tangbang W8-1772 for evaluation purpose.
http://www.tb-speaker.com/detail/1230_04/w8-1772.htm
I must say that they look a million.
Thus far we've only tested them in 16l sealed enclosures, the size based on simulation made in WinISD Pro Alpha.
The treble is well-balanced, neither over-analytical nor absent,
the midrange is still a bit hard, but I think it's just a matter of breaking it in, but there is a good speech-intelligibility. No tendency to shout or being nasal.
Bass is of course lacking, and this is where I need advice from You, since I only have experience with TL's and sealed enclosures for Hi-Fi, and none of these are suitable for this fullrangespeaker ;-)
There are many other ways to make bass, deep'n clean, like horns and various ML and quaterwave-styles, and a lot of You who are a lot more experienced than I to se which design will suit this speaker the best, and help with the math!
My evaluation of the speaker will of course be sent to Tangband, together with descriptions of the enclosures used, since they delivered the speakerunits, but the proprietary rights to any design comming from this forum will of course belong to this forum.
Is there anybody out there..........
who are willing to give a hand?
Hello again hm
Easy math would be nice, but there are a few issues I'd like to adress before we start our pocket calculators and XLS spreadsheets, just in order to understand the choises being made
-First issue is a chamber behind the speaker.
I've read somewhere that it will act as a low-pass filter to the horn, filtering out frequencies that can cause phase cancelations.
Is this true, and if so, how is it calculated.
-Second issue is the calculations of the horn it self: size of the hornthroat, expantion rate, area of the horn mouth.
I'm very well aware that the amount of bass, and the bass extension depends of these parameters, but are these things solely determined by math, or do experience play a part as well?
-Third issue is the hornmouth, or rather in wich direction it shall radiate, backwards, downwards or forwards.
What are the pro's and con's??
Please tell me if I'm wrong, but when facing backwards it will use the wall, or corner, behind it to enhance the output from the hornmouth, but also making the speaker more sensitive to where it is placed in the room.
When facing forward You'll hear everything that comes out of the hornmouth, good and bad!
Facing downwards can't just be a design issue, but is it a way to take pro's, and not the con's from the others??
hm said:
Easy math would be nice, but there are a few issues I'd like to adress before we start our pocket calculators and XLS spreadsheets, just in order to understand the choises being made
-First issue is a chamber behind the speaker.
I've read somewhere that it will act as a low-pass filter to the horn, filtering out frequencies that can cause phase cancelations.
Is this true, and if so, how is it calculated.
-Second issue is the calculations of the horn it self: size of the hornthroat, expantion rate, area of the horn mouth.
I'm very well aware that the amount of bass, and the bass extension depends of these parameters, but are these things solely determined by math, or do experience play a part as well?
-Third issue is the hornmouth, or rather in wich direction it shall radiate, backwards, downwards or forwards.
What are the pro's and con's??
Please tell me if I'm wrong, but when facing backwards it will use the wall, or corner, behind it to enhance the output from the hornmouth, but also making the speaker more sensitive to where it is placed in the room.
When facing forward You'll hear everything that comes out of the hornmouth, good and bad!
Facing downwards can't just be a design issue, but is it a way to take pro's, and not the con's from the others??
Hello,
1:
look my TUBA and a Sat horn for example,
more important for Basshorns, look my use of softfibre
you can reduce frequencies over 100 Hz.
a simulation is the best way to get the right size.
2:
if you take physically optimum you need 5,9 sqm for
40 Hz = not realistic, in living room is the lenght and flare rate important and the flare rate must be one oktave below the wished lowest frequenz.
3:
i use softfibre, so i like the direkt variation.
But for helping, it is better you tell us what a horn you will built and which driver.
If you know what you will construct, my easy math are:
Calculation of expo horns
If you have AH, AM, l,
k still lacks the flare rate:
ln (AM / AH) / l = k
so you can see the surface
each point out (Al):
INV ln (l * k) * AH = Al
l m, AH + AM + AL in square meters
By Al e.g. m in width and divide
you have the distance in meters
AH = Horn throat
AM = Horn mouth
k = flare rate
l = length
Lengths and flare rate VALUES
K VALUES:
0.37 ~ 10 Hz
0.55 ~ 15 Hz
0.7 ~ 19 Hz
0.9 ~ 25 Hz
1.1 ~ 30 Hz
1.3 ~ 35 Hz
1.48 ~ 40 Hz
About an octave above k plays the horn,
if the length matches. At BL horn lengths
over 3.4 m, you get a suck out
below 100 Hz
4/lamda lengths VALUES
3.4 m ~ 25 Hz
2.8 m ~ 30 Hz
2.4 m ~ 35 Hz
2.1 m ~ 40 Hz
1.7 m ~ 50 Hz
1.4 m ~ 60 Hz
1:
look my TUBA and a Sat horn for example,
more important for Basshorns, look my use of softfibre
you can reduce frequencies over 100 Hz.
a simulation is the best way to get the right size.
2:
if you take physically optimum you need 5,9 sqm for
40 Hz = not realistic, in living room is the lenght and flare rate important and the flare rate must be one oktave below the wished lowest frequenz.
3:
i use softfibre, so i like the direkt variation.
But for helping, it is better you tell us what a horn you will built and which driver.
If you know what you will construct, my easy math are:
Calculation of expo horns
If you have AH, AM, l,
k still lacks the flare rate:
ln (AM / AH) / l = k
so you can see the surface
each point out (Al):
INV ln (l * k) * AH = Al
l m, AH + AM + AL in square meters
By Al e.g. m in width and divide
you have the distance in meters
AH = Horn throat
AM = Horn mouth
k = flare rate
l = length
Lengths and flare rate VALUES
K VALUES:
0.37 ~ 10 Hz
0.55 ~ 15 Hz
0.7 ~ 19 Hz
0.9 ~ 25 Hz
1.1 ~ 30 Hz
1.3 ~ 35 Hz
1.48 ~ 40 Hz
About an octave above k plays the horn,
if the length matches. At BL horn lengths
over 3.4 m, you get a suck out
below 100 Hz
4/lamda lengths VALUES
3.4 m ~ 25 Hz
2.8 m ~ 30 Hz
2.4 m ~ 35 Hz
2.1 m ~ 40 Hz
1.7 m ~ 50 Hz
1.4 m ~ 60 Hz
Er, no offense, but what BLHs have you been looking at?
1 very rough back loaded horn 25ft long (7.62m). I've made no attempt at all to refine or reactance annul it -heck, it's only an exponential, rather than a ~optimal hyperbolic. Even so, I might be going blind, but I can't see a suckout below 100Hz. Come to that, I can't see a suckout above 100Hz either.
In fairness, I agree, the more you compromise the impedance matching at cutoff, the more response aberations you will get, but it's complete nonsense to say 'all BLHs have a suckout below 100Hz.' They don't.
1 very rough back loaded horn 25ft long (7.62m). I've made no attempt at all to refine or reactance annul it -heck, it's only an exponential, rather than a ~optimal hyperbolic. Even so, I might be going blind, but I can't see a suckout below 100Hz. Come to that, I can't see a suckout above 100Hz either.
In fairness, I agree, the more you compromise the impedance matching at cutoff, the more response aberations you will get, but it's complete nonsense to say 'all BLHs have a suckout below 100Hz.' They don't.
Attachments
most horn in my simus look something like the Kornett
simulations, scroll down, and compair it with real measurements
above,
http://www.hm-moreart.de/104.htm
your simu looks like a hornmouth simu without driver,
which program do you use?
simulations, scroll down, and compair it with real measurements
above,
http://www.hm-moreart.de/104.htm
your simu looks like a hornmouth simu without driver,
which program do you use?
No, red = combined response (driver & terminus). Software is Martin King's MathCAD worksheets, the accuracy of which is well known & has been confirmed by many sources, so if you were concerned about that, you don't need to be. Of course, the above isn't taking practical matters like size into consideration, but it's just to illustrate the point. As I say, I agree, most BLHs will have various response nulls etc as they are usually compromised more or less severely, but it's not a universal truth by any means.
Of course, the above isn't taking practical matters like size into consideration, but it's just to illustrate the point. As I say, I agree, most BLHs will have various response nulls etc as they are usually compromised more or less severely, but it's not a universal truth by any means.Gentlemen
It's very interesting to read Your discussions, wich brings me back to a part of my question.
How much is determined by math, and how much by experience.
I've been reading about horn-calculations at the Fullrangedriver website, and see that with ie. Lowther the throat ranges between 50 and 150cm2 as a rule.
This suggests to me that it is not a result of math, but rather experience (or guesswork).
Secondly, if there is a suck-out, is it not a result of poor low-pass filtering, causing phase-cancellation, maybe because of an incorrectly dimensioned compression chamber, or too little damping material?
I've been working a little with the formulas from the Fullrangedriver website, and the Hornresponse software, to see how my TB's behaved, and I must say that a lot of compromises has to be made, if they are to fit into a normal livingroom
Either the cut-off frequency shall be in the mid-bass, or they'll have to stand in a corner!
Does a normal expo-horn suit this driver at all????
Or shall I go for another kind of horn?
Even though I'm a Fostex-fan, and has been so for @25 years, I must admit that I like them better and better for every day.
I hope that they will be available for everyone in near future.
It's very interesting to read Your discussions, wich brings me back to a part of my question.
How much is determined by math, and how much by experience.
I've been reading about horn-calculations at the Fullrangedriver website, and see that with ie. Lowther the throat ranges between 50 and 150cm2 as a rule.
This suggests to me that it is not a result of math, but rather experience (or guesswork).
Secondly, if there is a suck-out, is it not a result of poor low-pass filtering, causing phase-cancellation, maybe because of an incorrectly dimensioned compression chamber, or too little damping material?
I've been working a little with the formulas from the Fullrangedriver website, and the Hornresponse software, to see how my TB's behaved, and I must say that a lot of compromises has to be made, if they are to fit into a normal livingroom
Either the cut-off frequency shall be in the mid-bass, or they'll have to stand in a corner!
Does a normal expo-horn suit this driver at all????
Or shall I go for another kind of horn?
Even though I'm a Fostex-fan, and has been so for @25 years, I must admit that I like them better and better for every day.
I hope that they will be available for everyone in near future.
Horn design is in principle, a whole lot of math. Some of the comments over on the FR driver site are approximate at best I'm afraid -especially that remark about throat sizes for Lowthers -you really should calculate a specific throat size optimal for the driver / horn / your intentions, not wing it.
Where experience (not guesswork -at least not as far as I'm concerned) comes in is when you compromise the horn, and introduce effects such as folding, which aren't covered by the basic horn math (although you can use other types to assist in that). Note that there are different types of base assumptions made for different horns profiles as well. Experience also plays a part in determining your own basic design goals as well of course.
A BLH doesn't have a compression chamber per se; the room is it's compression chamber. CCs are the sealed back-chamber in a front horn & are there to match the load on the rear of the driver cone to what the horn provides at the front (over-simplified but you get the idea). The suck-out Horst is refering to above will originate in line harmonics and an impedance mis-match at the mouth for a given tuning frequency. If you want to avoid it, you need an optimally sized mouth. If you reduce it from this point, you start getting standing waves (supersonic shockwaves) reflected from the mouth back up the horn. And so on & so forth.
Personally, I don't like exponential horns very much, but that's really more a matter of taste. You could certainly design one easily enough. For e.g., this is a quick exponential horn for it I roughed out, albeit a rather large one.
Where experience (not guesswork -at least not as far as I'm concerned) comes in is when you compromise the horn, and introduce effects such as folding, which aren't covered by the basic horn math (although you can use other types to assist in that). Note that there are different types of base assumptions made for different horns profiles as well. Experience also plays a part in determining your own basic design goals as well of course.
A BLH doesn't have a compression chamber per se; the room is it's compression chamber. CCs are the sealed back-chamber in a front horn & are there to match the load on the rear of the driver cone to what the horn provides at the front (over-simplified but you get the idea). The suck-out Horst is refering to above will originate in line harmonics and an impedance mis-match at the mouth for a given tuning frequency. If you want to avoid it, you need an optimally sized mouth. If you reduce it from this point, you start getting standing waves (supersonic shockwaves) reflected from the mouth back up the horn. And so on & so forth.
Personally, I don't like exponential horns very much, but that's really more a matter of taste. You could certainly design one easily enough. For e.g., this is a quick exponential horn for it I roughed out, albeit a rather large one.
Attachments
Hi Scottmoose.
Thank You
Then what do You call the chamber behind the speaker unit in a BLH, when there is a such?
Can You also then explain to me please, and others, what the differences are between the hornmouth facing for- vs. down- vs. backward apart from the esthetics?
I've seen Your Half Chang design for the Fostex FE-207E, and I like that, but will that design be suitable for the Tangband W8-1772??
Thank You
Then what do You call the chamber behind the speaker unit in a BLH, when there is a such?
Can You also then explain to me please, and others, what the differences are between the hornmouth facing for- vs. down- vs. backward apart from the esthetics?
I've seen Your Half Chang design for the Fostex FE-207E, and I like that, but will that design be suitable for the Tangband W8-1772??
Scottmoose
thanks
Hoffmeyer
back to you:
a single driver horn for the TB
IMO should be ~ 40 cm wide an asymetric montage, left and right,
to get enough mids.
The horn size is limited by the box size, lowther are to small IMO
if i compair FLH with BLH i found the suck out only by BLH´s
that is a reaction of driver and horn.
Expo horns are the best compromis, easy to calculate.
Try it like this,
height of driver zentrum = sit ear height
~44 cm wide,
max. enclosure volume,
take k 0,6
take l 2,5 m
open the last 50 cm with min. triple k
take the press chamber and the first m of the horn
in softfibre, to reduce box sound and all
"Schallschnellen" over 100 Hz
AH, o,oo1
with my formula you get an math AM of only 0,4 x 0,11 m
you construct the end with ~0,4 x 0,25 m
IMO 40 Hz are possible, asymetric montage let you decide
the small or the large side in direction to the listener
an you get enough mids by the baffle.
Box near a wall.
thanks
Hoffmeyer
back to you:
a single driver horn for the TB
IMO should be ~ 40 cm wide an asymetric montage, left and right,
to get enough mids.
The horn size is limited by the box size, lowther are to small IMO
if i compair FLH with BLH i found the suck out only by BLH´s
that is a reaction of driver and horn.
Expo horns are the best compromis, easy to calculate.
Try it like this,
height of driver zentrum = sit ear height
~44 cm wide,
max. enclosure volume,
take k 0,6
take l 2,5 m
open the last 50 cm with min. triple k
take the press chamber and the first m of the horn
in softfibre, to reduce box sound and all
"Schallschnellen" over 100 Hz
AH, o,oo1
with my formula you get an math AM of only 0,4 x 0,11 m
you construct the end with ~0,4 x 0,25 m
IMO 40 Hz are possible, asymetric montage let you decide
the small or the large side in direction to the listener
an you get enough mids by the baffle.
Box near a wall.
You're welcome. Yes, it will fit in the HC cabinet, with a couple of modifications -throat length will need to be reduced to 3/4in & depth of the throat (as in front - back) increased to 1.5in. A variation should be possible, although mass corner's a bit high. The HC is a rather extreme variation on the BLH of course, but it's still technically a BLH. Boxes like that tend to be refered to as BVRs (for Big Vent Reflex), which is quite a clever way of describing it, although a little deceptive, because most chambered BLHs can be considered as relations to the BR cabinet.
The chamber? Low pass filter chamber / acoustic filter chamber was how Olson (who invented it back in 1937) described it.
As for the direction the terminus faces, that tends to be a matter linked into the design goals / type, so it's difficult to make specific statements. A rearward firing mouth might (as in might) be a case of simple choice on the part of the designer for folding, or aesthetic considerations, or it may be because the horn is designed to be used in 1/4 or 1/8 radiation space (the latter being a corner horn) where the room boundaries continue the expansion & form the mouth itself.
Scottmoose,
your horn simu must be a large, might be a very large horn,
do you have some simus like Imp, movement?
Hoffmeyer
add to my last post,
a horn makes max. 3 Oktaven,
this depends on k, so my horn have a warm roll of
at 250 Hz, smal press chamber, look the measurements.
The TUBA has a large press chamber ~7 L than you
can get a roll of at 150 Hz with 20 dB Oktave,
good for Manger and JX92 but not for a 8" FR
so try the press chamber 2-3 L.
The manufacture measurements are made smooth and on
an IEC baffle, this shows more mids as in a normal box.
Only a "good" diagramm is a seller.
your horn simu must be a large, might be a very large horn,
do you have some simus like Imp, movement?
Hoffmeyer
add to my last post,
a horn makes max. 3 Oktaven,
this depends on k, so my horn have a warm roll of
at 250 Hz, smal press chamber, look the measurements.
The TUBA has a large press chamber ~7 L than you
can get a roll of at 150 Hz with 20 dB Oktave,
good for Manger and JX92 but not for a 8" FR
so try the press chamber 2-3 L.
The manufacture measurements are made smooth and on
an IEC baffle, this shows more mids as in a normal box.
Only a "good" diagramm is a seller.
It's a full-sized horn, yes, as I said. Note there's no sign of that sub 100Hz suckout... (OK, I'll let that pass as we're both essentially in agreement -if you reduce the size too far, you'll run into problems )
What's that? Other data? Have a handful. Excuse the leakage above Fh -frankly, I couldn't be bothered to refine it, as it was only supposed to be a very quick example.
)What's that? Other data? Have a handful. Excuse the leakage above Fh -frankly, I couldn't be bothered to refine it, as it was only supposed to be a very quick example.
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