TerryO said:
These were the units (they are Cal's). I used fatter felt than Terry was used, and it is head in place with the elastic band. Because of the square magnet -- no darts required. The felt removed some little peaks in the impedance response which can be directly attributed to the removal of some resonances or reflections.
dave
166ES-R cabinet ?
Am I alone in not being able to get excited about the Fostex recommended cabinet for the 166ES-R?
It's primarily the width of the front baffle that turns me off (although I'd also prefer a shallower cabinet).
I am trying to attach a sketch of an idea for a cabinet. Since I'm a newbie to horns, please tell me where I am crazy here. This cabinet would have an internal width of 6", thereby pretty much maintaining the Fostex recommended enclosure throat cross-sectional areas.
Even though I have little idea about what I am doing regarding horn design, something about this sketch does not look "right" to me. The sound path seems to be opening up into the "mouth" too soon. I'd also prefer a shallower cabinet, but I worry/wonder about the horizontal "wave guide" overlap. Is there some minimum "overlap" I should be maintaining?
Any help, advice, etc. will be greatly appreciated.
Sincerely,
Brad
Am I alone in not being able to get excited about the Fostex recommended cabinet for the 166ES-R?
It's primarily the width of the front baffle that turns me off (although I'd also prefer a shallower cabinet).
I am trying to attach a sketch of an idea for a cabinet. Since I'm a newbie to horns, please tell me where I am crazy here. This cabinet would have an internal width of 6", thereby pretty much maintaining the Fostex recommended enclosure throat cross-sectional areas.
Even though I have little idea about what I am doing regarding horn design, something about this sketch does not look "right" to me. The sound path seems to be opening up into the "mouth" too soon. I'd also prefer a shallower cabinet, but I worry/wonder about the horizontal "wave guide" overlap. Is there some minimum "overlap" I should be maintaining?
Any help, advice, etc. will be greatly appreciated.
Sincerely,
Brad
Attachments
Hi All
I'm a newbie and am very keen to bulild a pair of speakers
based on the Fostex fe166 speaker. As this will be my first speaker project, I am wanting to build something that has a great sound and is easy to build but not break the bank incase it doesn't sound any good. I have been reading the posts on this speaker and have a couple of questions for thse that know a lot more than me.
I noticed on Terry Cains site that he used 1 1/4" (32mm) side walls for his Single Horn Ben which seems similar to the recommended fe166 enclosure. The Cain and Cain speakers seem to be held in high regard and the cabinet work looks superb. Does this make a difference or will 15 mm be sufficient. (I've got to say that I feel sorry for you poor people that still do your calcs in imperial!).
Is there a significant differnce in the sound quality between the speaker based on the fe166 and the fe 208 ??
I have a good range of tools for doing the woodwork so the cabinetry is not a problem. The other speakers that caught my eye were Lynn Olsens Ariels.
Thanks in advance
Geoff
I'm a newbie and am very keen to bulild a pair of speakers
based on the Fostex fe166 speaker. As this will be my first speaker project, I am wanting to build something that has a great sound and is easy to build but not break the bank incase it doesn't sound any good. I have been reading the posts on this speaker and have a couple of questions for thse that know a lot more than me.
I noticed on Terry Cains site that he used 1 1/4" (32mm) side walls for his Single Horn Ben which seems similar to the recommended fe166 enclosure. The Cain and Cain speakers seem to be held in high regard and the cabinet work looks superb. Does this make a difference or will 15 mm be sufficient. (I've got to say that I feel sorry for you poor people that still do your calcs in imperial!).
Is there a significant differnce in the sound quality between the speaker based on the fe166 and the fe 208 ??
I have a good range of tools for doing the woodwork so the cabinetry is not a problem. The other speakers that caught my eye were Lynn Olsens Ariels.
Thanks in advance
Geoff
Geoff asks:
I have been reading the posts on this speaker and have a couple of questions for thse that know a lot more than me.
I noticed on Terry Cains site that he used 1 1/4" (32mm) side walls for his Single Horn Ben which seems similar to the recommended fe166 enclosure. The Cain and Cain speakers seem to be held in high regard and the cabinet work looks superb. Does this make a difference or will 15 mm be sufficient. (I've got to say that I feel sorry for you poor people that still do your calcs in imperial!).
Is there a significant differnce in the sound quality between the speaker based on the fe166 and the fe 208 ??
I have a good range of tools for doing the woodwork so the cabinetry is not a problem. The other speakers that caught my eye were Lynn Olsens Ariels.
~~~~~~~~~~~~~~~~~~~~~~~~
Geoff,
While I can't speak for Terry Cain, you should be aware that he sells his speakers and probably has good reasons for the use of 1 1/4" ( Yes, I love the Imperial System). Another factor is that he has a SOTA manufacturing facility and is able to layup his material in any configuration he deems necessary or desirable. I don't know, but he may be laminating 1" material with 1/8" ply on both sides to generate not only a stable, non-warping material, but he's taking advantage of it's inherent constrained layer effect.
And yes, his cabinet work is superb, some of the best I've ever come across.
The other item that you mentioned that I can comment on is the Ariel speakers that Lynn Olson designed. I love reading anything that he writes, but I have never heard a pair of Ariels that sounded good enough for me to want a pair. There are so many variations and configurations of these that I haven't heard, I'm reluctant to make an overall, general statement, so I'll give you my opinion instead.
So......... of the one's that I've heard and the amount of work involved building those cabinets, I'd go with another design and I believe you should, too.
Best Regards,
TerryO
I have been reading the posts on this speaker and have a couple of questions for thse that know a lot more than me.
I noticed on Terry Cains site that he used 1 1/4" (32mm) side walls for his Single Horn Ben which seems similar to the recommended fe166 enclosure. The Cain and Cain speakers seem to be held in high regard and the cabinet work looks superb. Does this make a difference or will 15 mm be sufficient. (I've got to say that I feel sorry for you poor people that still do your calcs in imperial!).
Is there a significant differnce in the sound quality between the speaker based on the fe166 and the fe 208 ??
I have a good range of tools for doing the woodwork so the cabinetry is not a problem. The other speakers that caught my eye were Lynn Olsens Ariels.
~~~~~~~~~~~~~~~~~~~~~~~~
Geoff,
While I can't speak for Terry Cain, you should be aware that he sells his speakers and probably has good reasons for the use of 1 1/4" ( Yes, I love the Imperial System). Another factor is that he has a SOTA manufacturing facility and is able to layup his material in any configuration he deems necessary or desirable. I don't know, but he may be laminating 1" material with 1/8" ply on both sides to generate not only a stable, non-warping material, but he's taking advantage of it's inherent constrained layer effect.
And yes, his cabinet work is superb, some of the best I've ever come across.
The other item that you mentioned that I can comment on is the Ariel speakers that Lynn Olson designed. I love reading anything that he writes, but I have never heard a pair of Ariels that sounded good enough for me to want a pair. There are so many variations and configurations of these that I haven't heard, I'm reluctant to make an overall, general statement, so I'll give you my opinion instead.
So......... of the one's that I've heard and the amount of work involved building those cabinets, I'd go with another design and I believe you should, too.
Best Regards,
TerryO
just a potential concern
i might be wrong here, as i am not too knowledgeable about fostex's horn theory, but i think that basically the longer the horn, the theoretically lower the cutoff frequency is. I could fill your ears with some horn and wind instrument mumbo jumbo, but basically, I think that i am getting some pretty low frequencies out of mine, and they are in horns that are definitely longer than the reccomended length, so i must slightly criticize your design for potentially not being long enough for the significant amount of low frequency energy that these drivers can produce. but then again, i might be full of you know what.
clark
i might be wrong here, as i am not too knowledgeable about fostex's horn theory, but i think that basically the longer the horn, the theoretically lower the cutoff frequency is. I could fill your ears with some horn and wind instrument mumbo jumbo, but basically, I think that i am getting some pretty low frequencies out of mine, and they are in horns that are definitely longer than the reccomended length, so i must slightly criticize your design for potentially not being long enough for the significant amount of low frequency energy that these drivers can produce. but then again, i might be full of you know what.
clark
Re: double horn
Once you have designed the horn, you just bifurcate it. The mouth & length stay the same. If you design for a larger mouth you will have a longer horn. Doubling the mouth doesn't double the length thou since the mouth size increases exponentially to the length.
solutions to 2 different issues.
dave
Tyimo said:
Once you have designed the horn, you just bifurcate it. The mouth & length stay the same. If you design for a larger mouth you will have a longer horn. Doubling the mouth doesn't double the length thou since the mouth size increases exponentially to the length.
solutions to 2 different issues.
dave
Sorry, let me re-ask the question, maybe I can be clearer if I use more words.
As I understand it,
In the context of mathematical modeling,
A double horn is the equivalent of
Two identical (straight or folded) horns.
Which may be easier to visualize (and will model the same as)
starting with a straight bifurcated horn,
then removing the dividing wall, leaving a single horn,
which would have the length of one horn, and the cross-section (and mouth diameter) of two horns.
If, and only if, the mouths are close enough to interact.
So, a double horn with an 8 foot path length in each section with two mouths of 23.5 x 9.5 inches, would be the equivalent of a single horn with an 8 foot path length (not 16), and a mouth of 47 x 9.5 inches.
(Assuming the mouths are close enough to act as one).
Is this correct?
(I think this is what Tyimo was saying?)
And this is why making a double horn by simply stacking two of the factory recommended designs (with the top one inverted), being fed by a common driver and compression chamber would not work? (The length remains the same, but the expansion ratio does not?)
So to make a double horn, I should start from scratch?
(Compression chamber, throat, path length, expansion, mouth).
I’m still trying to decide what cabinets to try these drivers in first, and unfortunately the list of things I want to try keeps getting longer....
1. The factory design,
2. Making it into a double horn,
3. A Decware Corner Horn,
4. A Lowther TP-1 ISIS corner horn,
5. A Nagaoka D-168
6. Using Martin King’s MathCad model to design something specifically for this driver.
7. Build something using two drivers per cabinet to increase efficiency, and hope comb filtering doesn’t kill it?
As I understand it,
In the context of mathematical modeling,
A double horn is the equivalent of
Two identical (straight or folded) horns.
Which may be easier to visualize (and will model the same as)
starting with a straight bifurcated horn,
then removing the dividing wall, leaving a single horn,
which would have the length of one horn, and the cross-section (and mouth diameter) of two horns.
If, and only if, the mouths are close enough to interact.
So, a double horn with an 8 foot path length in each section with two mouths of 23.5 x 9.5 inches, would be the equivalent of a single horn with an 8 foot path length (not 16), and a mouth of 47 x 9.5 inches.
(Assuming the mouths are close enough to act as one).
Is this correct?
(I think this is what Tyimo was saying?)
And this is why making a double horn by simply stacking two of the factory recommended designs (with the top one inverted), being fed by a common driver and compression chamber would not work? (The length remains the same, but the expansion ratio does not?)
So to make a double horn, I should start from scratch?
(Compression chamber, throat, path length, expansion, mouth).
I’m still trying to decide what cabinets to try these drivers in first, and unfortunately the list of things I want to try keeps getting longer....
1. The factory design,
2. Making it into a double horn,
3. A Decware Corner Horn,
4. A Lowther TP-1 ISIS corner horn,
5. A Nagaoka D-168
6. Using Martin King’s MathCad model to design something specifically for this driver.
7. Build something using two drivers per cabinet to increase efficiency, and hope comb filtering doesn’t kill it?
Hey Robert,
I'm still pretty new to horns myself, but I don't think "areas" add - just dBs.
The mouth determines the cut-off freq for the sound coming out of that horn. You could put 2, or more side by side and each would still have a cut-off freq dictated by the area of the mouth at the end of that horn.
As long as the sound waves were in phase (from the different horns), the amplitudes would add - but this would not effect the cut-off freqs of each separate horn.
Sincerely,
brad
I'm still pretty new to horns myself, but I don't think "areas" add - just dBs.
The mouth determines the cut-off freq for the sound coming out of that horn. You could put 2, or more side by side and each would still have a cut-off freq dictated by the area of the mouth at the end of that horn.
As long as the sound waves were in phase (from the different horns), the amplitudes would add - but this would not effect the cut-off freqs of each separate horn.
Sincerely,
brad
serenechaos said:
What you said is pretty much OK except the quoted bit... take a horn with length L & mouth A. Divide it in 2 (add a partition), then fold these 2 horns (in a mirror fashion usually). You get 2 subhorns of length L & area A/2. You can start the division anywhere along the horn.
dave
Hi Brad,
I think it depends, if the mouth areas are next to each other for two identical horns then I think the cut-off frequency changes. The cut-off frequency is detemined by the acoustic impedance of the mouth which is generated by summing the pressure contributions from a large collection of simple sources spread over the mouth area. Two mouths beside each other will "see" the neighbor and this will change the acousitic impedance. The size, shape, and any reflective surfaces near the mouth are important when calculating the acoustic impedance and cut-off frequency.
Dave and serenechaos,
The split over and under horn geometry bothers me, I am not sure things are that simple. First the lower horn mouth sees a reflection from the floor boundary condition which in effect doubles the acoustic impedance. The upper horn mouth does not see this boundary condition. Both horn mouths will feel the other, but not to the extent of being very close, and this will influence the acousitic impedance and therefore the cut-off frequency. But due to the floor refection boundary condition at the lower mouth, I am not sure the two separate horns will behave the same. I don't know how big an impact this would be but I guess one could calculate the two and see if it is a concern.
I think it depends, if the mouth areas are next to each other for two identical horns then I think the cut-off frequency changes. The cut-off frequency is detemined by the acoustic impedance of the mouth which is generated by summing the pressure contributions from a large collection of simple sources spread over the mouth area. Two mouths beside each other will "see" the neighbor and this will change the acousitic impedance. The size, shape, and any reflective surfaces near the mouth are important when calculating the acoustic impedance and cut-off frequency.
Dave and serenechaos,
The split over and under horn geometry bothers me, I am not sure things are that simple. First the lower horn mouth sees a reflection from the floor boundary condition which in effect doubles the acoustic impedance. The upper horn mouth does not see this boundary condition. Both horn mouths will feel the other, but not to the extent of being very close, and this will influence the acousitic impedance and therefore the cut-off frequency. But due to the floor refection boundary condition at the lower mouth, I am not sure the two separate horns will behave the same. I don't know how big an impact this would be but I guess one could calculate the two and see if it is a concern.
Thanks for the information Terry.
Ah well back to the drawing board.
The short list is now down to the following:
Scanspeak reference monitor
Jaguar 2
Borealis
But just curious, how would the Fostex FE208 sigma in the BLH cabinet from the Fostex website sound with the T90A tweeter instead of the recomended T900A. Has anyone made this??
Cheers
Geoff
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