panomaniac said:
Hi,
I fully understand that the FR8C is totally incompatible with the enclosures that I have made.
There are 2 options for this situation.
i. To build a bigger enclosure for the FR8C
ii. Find a pair of replacement for this enclousre.
I am hoping to find the 2nd solution as I have a problem with space and free time to build them
Hi,
I fully understand that the FR8C is totally incompatible with the enclosures that I have made.
There are 2 options for this situation.
i. To build a bigger enclosure for the FR8C
ii. Find a pair of replacement for this enclousre.
I am hoping to find the 2nd solution as I have a problem with space and free time to build them
If you observe the freq. response I posted you will find the the high freq. response is not very good.
I would not use it as a full ranger, you have to supplement it with a tweeter if you want to build another cabinet for it. The bass would be adequate if the cabinet is large enough.
FYI the FR8C I measured comes from Singapore's distributor which you may also have bought them from. It does not measure very well not in accordance with the manu. spec.. It is not the distrisbutor's fault you have to point the finger at the manufacturer.
thought I'd weigh in on this one....
because I actually have first hand knowledge of both the Hemp drivers, and the "spiral horns" (theoretically).
4 or 5 years ago, I actually fit the behaviour of the "spiral horns" to a mathematical model, and realized that essentially hanbei's idea was to create a vented box, tune the box to the Fs of the driver, create a "spiral horn" tuned to the driver Fs, and create a "spiral horn" within the vent. This seemed to fit the behaviour of his "design", even though he had/has no real idea of what was /is actually going on. (I know this because I supplied him with the mathematics that was needed to explain it).
The original "spiral horn" idea can be made to work quite nicely, at least in concept. The "angular spiral enclosure" on the other hand seems quite convoluted and overly optimistic. I have no idea how to actually even try to use mathematics to describe its behaviour.
Regarding the FR8c from Hemp Acoustics (Canada), I've had a pair for almost three years. Mine have been modified by planet10 (not ENABLed, but whizzers cut off and FE206 style phase plugs added). The baskets have had Dave's typical "tweak" done to them, and some puzzle coat or other varnish had been painted on.
In this case there seems to be what I would call a more extended and smoother response in the high frequencies, followed by better imaging and virtually no "beaming". Note, these mods are not sanctioned or approved by Hemp Acoustics, and do so at your own risk.
The modded drivers work well in a 20 litre vented box tuned to 42 Hz, planet10 "Demetris" enclosures and very well in "JE Labs style" open baffles. I have never put them in the large BR recommended enclosures , but the enclosures need to be in the 75-85 litre range to work correctly.
hope that helps. Oh and the FR8c drivers need 100+ hours on them to loosen up.
hope that helps
stew
because I actually have first hand knowledge of both the Hemp drivers, and the "spiral horns" (theoretically).
4 or 5 years ago, I actually fit the behaviour of the "spiral horns" to a mathematical model, and realized that essentially hanbei's idea was to create a vented box, tune the box to the Fs of the driver, create a "spiral horn" tuned to the driver Fs, and create a "spiral horn" within the vent. This seemed to fit the behaviour of his "design", even though he had/has no real idea of what was /is actually going on. (I know this because I supplied him with the mathematics that was needed to explain it).
The original "spiral horn" idea can be made to work quite nicely, at least in concept. The "angular spiral enclosure" on the other hand seems quite convoluted and overly optimistic. I have no idea how to actually even try to use mathematics to describe its behaviour.
Regarding the FR8c from Hemp Acoustics (Canada), I've had a pair for almost three years. Mine have been modified by planet10 (not ENABLed, but whizzers cut off and FE206 style phase plugs added). The baskets have had Dave's typical "tweak" done to them, and some puzzle coat or other varnish had been painted on.
In this case there seems to be what I would call a more extended and smoother response in the high frequencies, followed by better imaging and virtually no "beaming". Note, these mods are not sanctioned or approved by Hemp Acoustics, and do so at your own risk.
The modded drivers work well in a 20 litre vented box tuned to 42 Hz, planet10 "Demetris" enclosures and very well in "JE Labs style" open baffles. I have never put them in the large BR recommended enclosures , but the enclosures need to be in the 75-85 litre range to work correctly.
hope that helps. Oh and the FR8c drivers need 100+ hours on them to loosen up.
hope that helps
stew
ttan98 said:
Based on my limited hours of listening to these drivers, the HF is still decent and acceptable to me, except for a few shouting.
There is only 1 distributor in Singapore and both of our drivers are form the same source
No pointing of finger here, my failure in this project is due to my insuffient research and ignorance
Re: thought I'd weigh in on this one....
Hi Stew,
Thanks for your input.
I have already given up hopes on project until I saw your reply. May I know how did the FR8C sounded in the 20L box, especially the LF?
I am also curious on what improvements to expects after the break-in period of >100hrs?
Is there still any hopes for my Hemps to work in my enclosures?
Nanook said:
Hi Stew,
Thanks for your input.
I have already given up hopes on project until I saw your reply. May I know how did the FR8C sounded in the 20L box, especially the LF?
I am also curious on what improvements to expects after the break-in period of >100hrs?
Is there still any hopes for my Hemps to work in my enclosures?
sound of 20 litre enclosures...
was quite enjoyable. Not threadbare or lean sounding. Full-bodied, excellent imaging. They played at least 1/2 octave lower than my Castle Durham 900s, reportedly good to 65 Hz, so I'm guessing at low 40Hz (-3dB point).
If you remove all the plates within your enclosures, and brace the enclosure, then try tuning them to 42Hz (this is what the Aperto is tuned to), I think you will enjoy them. And what do you have to lose? A 56 litre enclosure tuned to 44Hz should require a port that is 68mm in diameter and 59mm long (from linear's LSD pro).
You can do much worse than listening to sreten and panomaniac. Both have proven to provide consistently good advice over the years. By the way, the Demetris are very good with the Hemps installed, and a small amount of BSC applied--the best enclosure I've heard the Hemps in (not including the "JE Labs style" open baffle). Hope that helps.
stew
was quite enjoyable. Not threadbare or lean sounding. Full-bodied, excellent imaging. They played at least 1/2 octave lower than my Castle Durham 900s, reportedly good to 65 Hz, so I'm guessing at low 40Hz (-3dB point).
If you remove all the plates within your enclosures, and brace the enclosure, then try tuning them to 42Hz (this is what the Aperto is tuned to), I think you will enjoy them. And what do you have to lose? A 56 litre enclosure tuned to 44Hz should require a port that is 68mm in diameter and 59mm long (from linear's LSD pro).
You can do much worse than listening to sreten and panomaniac. Both have proven to provide consistently good advice over the years. By the way, the Demetris are very good with the Hemps installed, and a small amount of BSC applied--the best enclosure I've heard the Hemps in (not including the "JE Labs style" open baffle). Hope that helps.
stew
Re: sound of 20 litre enclosures...
Yes indeedy-do! The Demetri design seems to be tailor fit for the FR8c. NOT a small box.
I agree with Stew, knock out the spiral baffles and tune the box, you may have a fun speaker. No harm in trying.
As to what driver may work better in that angular spiral box, well..... your guess is as good as mine (maybe better).
Nanook said:
Yes indeedy-do! The Demetri design seems to be tailor fit for the FR8c. NOT a small box.
I agree with Stew, knock out the spiral baffles and tune the box, you may have a fun speaker. No harm in trying.
As to what driver may work better in that angular spiral box, well..... your guess is as good as mine (maybe better).
This is the 1/2 space response of the FR8 in a 20 litre box tuned to 41Hz so 'lean sounding' they will certainly not be, especially with room-gain factored in.
Machining out the internal panels wouldn't be easy, but if you could manage it, & install a vent, at least you could rescue something.
Stew, re the angular spirals, you could model / assume them as a chambered QW cabinet, some of them with some additional mass-loading applied. Exactly what he's hoping to achieve with them though, I don't know.
Machining out the internal panels wouldn't be easy, but if you could manage it, & install a vent, at least you could rescue something.
Stew, re the angular spirals, you could model / assume them as a chambered QW cabinet, some of them with some additional mass-loading applied. Exactly what he's hoping to achieve with them though, I don't know.
Attachments
"...my failure in this project is due to my insuffient research and ignorance"
Join the club! Your statement holds true with my endevors into all fields of speaker building (and I suspect numerous others). Many years ago it was building big subs for cars and failing at first due to lack of understanding the basics. Then it was struggling with crossover design until I became proficient with Jeff Bagby's PCD. Most recently the failures have been trying to defy physics concerning fullrange drivers. In each case I have been saved by building or basing my build on popular and proven designs. Take the advice that you here on this forum and start over with what is recommended. Failure is perfectly acceptable when coupled with willingness to listen and start over, especially when the suggestions are coming from helpfull and wise people such as the ones found here... they've helped me more than once.
Join the club! Your statement holds true with my endevors into all fields of speaker building (and I suspect numerous others). Many years ago it was building big subs for cars and failing at first due to lack of understanding the basics. Then it was struggling with crossover design until I became proficient with Jeff Bagby's PCD. Most recently the failures have been trying to defy physics concerning fullrange drivers. In each case I have been saved by building or basing my build on popular and proven designs. Take the advice that you here on this forum and start over with what is recommended. Failure is perfectly acceptable when coupled with willingness to listen and start over, especially when the suggestions are coming from helpfull and wise people such as the ones found here... they've helped me more than once.
cjctan said:
Based on my limited hours of listening to these drivers, the HF is still decent and acceptable to me, except for a few shouting.
There is only 1 distributor in Singapore and both of our drivers are form the same source
No pointing of finger here, my failure in this project is due to my insuffient research and ignorance
The rising freq.due to break up of the cone is really unacceptable, the manufacturer data does NOT show the rising response. These drivers are from my friend otherwise I would have returned them if you still want use them as a fullranger.
If you want to use a full ranger in your existing or new cabinet I suggest get another brand, if not in the longer term you will MOST likely dump this driver and upgrade to a better one hence spending more money again.
If you want to retain it then add another tweeter it is still acceptable. see attachment.
X-over around 3.5Khz
Attachments
Re: scottmoose...
er, that's what I just said...
If it's a +10db at Fs or Fb/p that he wanted with the originals (I assume that's over the IB curve), he's going to have problems with the smaller examples as you still need sufficient volume to provide it, even with a very long vent (which has far too small a CSA).
Nanook said:
er, that's what I just said...
Scottmoose said:
If it's a +10db at Fs or Fb/p that he wanted with the originals (I assume that's over the IB curve), he's going to have problems with the smaller examples as you still need sufficient volume to provide it, even with a very long vent (which has far too small a CSA).
Re: sound of 20 litre enclosures...
Hi Stew,
I guess the whole box will collasped after I rip those plates out... It would be a major overhaul which I will not embark on. My current objective is either to improve the current situation, if possible, or abandon this project and start on a new project when I have the time for it......
Nanook said:
Hi Stew,
I guess the whole box will collasped after I rip those plates out... It would be a major overhaul which I will not embark on. My current objective is either to improve the current situation, if possible, or abandon this project and start on a new project when I have the time for it......
fwater said:
Hi,
Failure is a part of the DIY process which to me is not the end of the world and I can take it well. Just that I would like to try to do remedies before I throw in my white towel
I believe I will enjoy the results of my next speaker project even more if it is a successful one. Maybe some will find my thread as some whinings but I really apprreciated all the comments/advises that I received so far.
ttan98 said:
Thanks again for the information on the plottings.
I understand that this driver have some "issues" in the practical world. Perhaps some tweakings such as those done of Stew's drivers are necessary.
I am game on to try out some tweaking on the drivers as long as the tweaks are within my capabilities
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