I wished my story was more adventures...like I fell down on the journey from camp 2 to camp 3 while climbing Mount Everest...
Silly me... I was on my way to do the daily shopping and fell over a loose tile in the pavement... So yes, I agree I have to pay more attention (or just die on the spot...haha)
R.
Silly me... I was on my way to do the daily shopping and fell over a loose tile in the pavement... So yes, I agree I have to pay more attention (or just die on the spot...haha)
R.
As said I am a bit bruised and everything was at a standstill but today the filter parts arrived so I am going to give it a try.. I will keep you posted (I sure hope it is the solution..).
R.
Ooh, you did get banged up a bit then, or are you old enough like me to take longer to heal? Regardless, hope you soon recover completely.
GM
GM
Hmm, may need a capacitor in parallel also to 'let through' some of the extreme highs to tonally balance it out to the driver's usable HF limit, making this what's commonly called a 'CD horn EQ' filter.
GM
Off course it is not my age... Imagine this I am two meters tall, weigh a 100 kilo's and I walk quite fast.. And my feet stopt moving because they met a stone.. the rest of my body did not stopt and so I took a "dive" "into" the pavement.. Lets say diving into concrete is something different that diving into water...
Do you have a suggestion for the value of this cap?
R.
Well, not of course to me at the time since I'd no clue about you, though being near enough to a foot taller and 45 lbs heavier than me, I can see how a hard landing could be devastating.
Without access to any of my tech 'library', not a clue beyond a 1/8-1 uF is the usual range for compression horns, but I imagine the Philips rolls off somewhat lower, so maybe start with the ~universal 2.2 uF [~10 kHz?] found in many old two ways if it's an 8 ohm driver.
I haven't looked at any of MJK's BSC docs, but may be of some help:
http://www.quarter-wave.com/General/BSC_Sizing.pdf
http://www.quarter-wave.com/General/BSC_Variable.pdf
http://www.quarter-wave.com/General/BSC_Calculator.xls
Loudspeaker Diffraction Loss and Baffle Step Compensation Circuits
GM
Without access to any of my tech 'library', not a clue beyond a 1/8-1 uF is the usual range for compression horns, but I imagine the Philips rolls off somewhat lower, so maybe start with the ~universal 2.2 uF [~10 kHz?] found in many old two ways if it's an 8 ohm driver.
I haven't looked at any of MJK's BSC docs, but may be of some help:
http://www.quarter-wave.com/General/BSC_Sizing.pdf
http://www.quarter-wave.com/General/BSC_Variable.pdf
http://www.quarter-wave.com/General/BSC_Calculator.xls
Loudspeaker Diffraction Loss and Baffle Step Compensation Circuits
GM
Thanks GM.
I have the 2,2 uF here from an old project. So I will go and try that this afternoon.
R.
I have the 2,2 uF here from an old project. So I will go and try that this afternoon.
R.
I have placed the caps. So now the filter consists out 0,82mH, 6,8Ohm, 2,2uF. I think the sound of the highs and mids has improved a lot.
But I am not there yet... The bass is there but stays in an around the box until you drive the system hard...
Can I improve this by stuffing or do I have to get my tools out and change something about the the port opening/length?
R.
But I am not there yet... The bass is there but stays in an around the box until you drive the system hard...
Can I improve this by stuffing or do I have to get my tools out and change something about the the port opening/length?
R.
Not sure what you mean plus until the filter is for sure correct, i.e. the highs sound balanced to the mids, to mid-bass, to bass, which usually requires using an equalizer or similar to BW limit as required to reduce the BW on either side of it from influencing it.....
This in turn is all affected by the room of course, so ideally needs to be done at the listening position..........
If you mean the lows are rolled off, then stuffing will just make it worse, so wondering how much damping is already in the cab as normally lining one wall, top, back with 1" acoustic fiberglass insulation is plenty if the vented cab's aspect ratio isn't too far from the golden ratio. Note that normally there shouldn't be any damping around/near the vent and if the cab 'booms' or 'rings', then one normally damps just the vent till it doesn't and no more.
This equates to ~0.2 lbs/ft^3 stuffing density of loose polyfil as best I can tell from using MJK's MathCad software Vs a few [crudely] measured responses of vented cabs I built long ago and still have my notes on, so what did you use/do?
Also, I see the vent size, but not the cab's net volume [Vb] plus without access to my notes and not finding this driver's specs, my dim memory says that the Vb needs to be quite large due to a high Qts, but from your picture it looks fairly small and I see Inductor mentions 104 L tuned to ~34 Hz, so is this it?
Anyway, if true, then the part about needing a lot of power to hear the LF makes sense due to the vent 'choking' the driver in an already too small cab, i.e. the response 'ballooning' up [making it more under-damped] in the mid-bass, which further increases the driver's Qts with increasing power due to rapid VC heating, which in turns makes the cab increasingly too small.........
If true, then 'stick a sock in it' [a colloquialism used to not so politely tell someone to shut up] so to speak by damping the vent with quite literally a cotton sock since it's big enough, i.e. don't pack it in, just slide it in to partially damp/block it. This should lower tuning a bit to 'bleed off' some of the cab's high Q tuning.
Another more long term solution if this helps is to 'pack' it with drinking straws, fine tuning it by how long they are, so ideally would need to start with longer than vent length straws and shorten as required.
FWIW, I tightly stretch [layers as required] of scrap speaker grill or expanded knit material over the vent and some folks use coffee machine filters, pieces of felt or open cell foam plugs or similar, so plenty of cheap/free options available to experiment with.
Still, long term, I assume from memory that a much larger cab is required for best overall performance or dial out more of the mids/HF response with the filter and/or listen as far off axis as it takes th get the mids on down sounding 'right', then increasing the cap value as required to 'lift up' the extreme HF to match.
GM
This in turn is all affected by the room of course, so ideally needs to be done at the listening position..........
If you mean the lows are rolled off, then stuffing will just make it worse, so wondering how much damping is already in the cab as normally lining one wall, top, back with 1" acoustic fiberglass insulation is plenty if the vented cab's aspect ratio isn't too far from the golden ratio. Note that normally there shouldn't be any damping around/near the vent and if the cab 'booms' or 'rings', then one normally damps just the vent till it doesn't and no more.
This equates to ~0.2 lbs/ft^3 stuffing density of loose polyfil as best I can tell from using MJK's MathCad software Vs a few [crudely] measured responses of vented cabs I built long ago and still have my notes on, so what did you use/do?
Also, I see the vent size, but not the cab's net volume [Vb] plus without access to my notes and not finding this driver's specs, my dim memory says that the Vb needs to be quite large due to a high Qts, but from your picture it looks fairly small and I see Inductor mentions 104 L tuned to ~34 Hz, so is this it?
Anyway, if true, then the part about needing a lot of power to hear the LF makes sense due to the vent 'choking' the driver in an already too small cab, i.e. the response 'ballooning' up [making it more under-damped] in the mid-bass, which further increases the driver's Qts with increasing power due to rapid VC heating, which in turns makes the cab increasingly too small.........
If true, then 'stick a sock in it' [a colloquialism used to not so politely tell someone to shut up] so to speak by damping the vent with quite literally a cotton sock since it's big enough, i.e. don't pack it in, just slide it in to partially damp/block it. This should lower tuning a bit to 'bleed off' some of the cab's high Q tuning.
Another more long term solution if this helps is to 'pack' it with drinking straws, fine tuning it by how long they are, so ideally would need to start with longer than vent length straws and shorten as required.
FWIW, I tightly stretch [layers as required] of scrap speaker grill or expanded knit material over the vent and some folks use coffee machine filters, pieces of felt or open cell foam plugs or similar, so plenty of cheap/free options available to experiment with.
Still, long term, I assume from memory that a much larger cab is required for best overall performance or dial out more of the mids/HF response with the filter and/or listen as far off axis as it takes th get the mids on down sounding 'right', then increasing the cap value as required to 'lift up' the extreme HF to match.
GM
Hi GM,
Thanks for your input. I am bit of a slow reader (long story). I will go thru it and if I have questions or results I will come back to you.
R.
Thanks for your input. I am bit of a slow reader (long story). I will go thru it and if I have questions or results I will come back to you.
R.
Greets!
I sympathize as it took me a long time to type it since somewhere along the line my attention span has increasingly relapsed to that of ~ a 2 year old. 🙁
GM
I sympathize as it took me a long time to type it since somewhere along the line my attention span has increasingly relapsed to that of ~ a 2 year old. 🙁
GM
After seeing my reply I saw it was very hard to read so here's the post again with some color.. to make it more readable.
Sorry...
Originally Posted by GM View Post
Not sure what you mean plus until the filter is for sure correct, i.e. the highs sound balanced to the mids, to mid-bass, to bass, which usually requires using an equalizer or similar to BW limit as required to reduce the BW on either side of it from influencing it.....
Well I find it very difficult to describe what I hear
This in turn is all affected by the room of course, so ideally needs to be done at the listening position..........
I know, and these drivers have an impossible small sweetspot.
If you mean the lows are rolled off, then stuffing will just make it worse, so wondering how much damping is already in the cab as normally lining one wall, top, back with 1" acoustic fiberglass insulation is plenty if the vented cab's aspect ratio isn't too far from the golden ratio. Note that normally there shouldn't be any damping around/near the vent and if the cab 'booms' or 'rings', then one normally damps just the vent till it doesn't and no more.
Reading your comment on stuffing, I think I have to much stuffing and will test this fortunately I did fastened it yet.
This equates to ~0.2 lbs/ft^3 stuffing density of loose polyfil as best I can tell from using MJK's MathCad software Vs a few [crudely] measured responses of vented cabs I built long ago and still have my notes on, so what did you use/do?
As said I get lost in the technical bit... So I did no maths on the stuffing.
Also, I see the vent size, but not the cab's net volume [Vb] plus without access to my notes and not finding this driver's specs, my dim memory says that the Vb needs to be quite large due to a high Qts, but from your picture it looks fairly small and I see Inductor mentions 104 L tuned to ~34 Hz, so is this it?
To give a idea of my world... I read a lot on speakers and there parameters. Unfortunately the theory does not stick. So every time I read this kind of text I have to look up what Vb, Ve, Vas etc means. 3 Years ago I had a stroke and I did fully recovered but concentrating and remembering stuff is got even worse..To put it mildly this very irritating and tiering. But yes is 104L, 34Hz.
Anyway, if true, then the part about needing a lot of power to hear the LF makes sense due to the vent 'choking' the driver in an already too small cab, i.e. the response 'ballooning' up [making it more under-damped] in the mid-bass, which further increases the driver's Qts with increasing power due to rapid VC heating, which in turns makes the cab increasingly too small.........
If true, then 'stick a sock in it' [a colloquialism used to not so politely tell someone to shut up] so to speak by damping the vent with quite literally a cotton sock since it's big enough, i.e. don't pack it in, just slide it in to partially damp/block it. This should lower tuning a bit to 'bleed off' some of the cab's high Q tuning.
This is confusing for me, the driver gets choked and then you stuff the vent? Doesn't chocking mean more air is needed so the vent needs opening up?
Another more long term solution if this helps is to 'pack' it with drinking straws, fine tuning it by how long they are, so ideally would need to start with longer than vent length straws and shorten as required.
Clear
FWIW, I tightly stretch [layers as required] of scrap speaker grill or expanded knit material over the vent and some folks use coffee machine filters, pieces of felt or open cell foam plugs or similar, so plenty of cheap/free options available to experiment with.
Clear
Still, long term, I assume from memory that a much larger cab is required for best overall performance or dial out more of the mids/HF response with the filter and/or listen as far off axis as it takes th get the mids on down sounding 'right', then increasing the cap value as required to 'lift up' the extreme HF to match.
Yes the cab needs to bigger that is very clear now, but inpatient as I am I went on with the finish of the cabinet and it would be a shame to throw it away. What I do have in mind is to get another driver which has a beter match with the cabinet but that needs funding. (I know this is reverse engineering)
Sorry...
Originally Posted by GM View Post
Not sure what you mean plus until the filter is for sure correct, i.e. the highs sound balanced to the mids, to mid-bass, to bass, which usually requires using an equalizer or similar to BW limit as required to reduce the BW on either side of it from influencing it.....
Well I find it very difficult to describe what I hear
This in turn is all affected by the room of course, so ideally needs to be done at the listening position..........
I know, and these drivers have an impossible small sweetspot.
If you mean the lows are rolled off, then stuffing will just make it worse, so wondering how much damping is already in the cab as normally lining one wall, top, back with 1" acoustic fiberglass insulation is plenty if the vented cab's aspect ratio isn't too far from the golden ratio. Note that normally there shouldn't be any damping around/near the vent and if the cab 'booms' or 'rings', then one normally damps just the vent till it doesn't and no more.
Reading your comment on stuffing, I think I have to much stuffing and will test this fortunately I did fastened it yet.
This equates to ~0.2 lbs/ft^3 stuffing density of loose polyfil as best I can tell from using MJK's MathCad software Vs a few [crudely] measured responses of vented cabs I built long ago and still have my notes on, so what did you use/do?
As said I get lost in the technical bit... So I did no maths on the stuffing.
Also, I see the vent size, but not the cab's net volume [Vb] plus without access to my notes and not finding this driver's specs, my dim memory says that the Vb needs to be quite large due to a high Qts, but from your picture it looks fairly small and I see Inductor mentions 104 L tuned to ~34 Hz, so is this it?
To give a idea of my world... I read a lot on speakers and there parameters. Unfortunately the theory does not stick. So every time I read this kind of text I have to look up what Vb, Ve, Vas etc means. 3 Years ago I had a stroke and I did fully recovered but concentrating and remembering stuff is got even worse..To put it mildly this very irritating and tiering. But yes is 104L, 34Hz.
Anyway, if true, then the part about needing a lot of power to hear the LF makes sense due to the vent 'choking' the driver in an already too small cab, i.e. the response 'ballooning' up [making it more under-damped] in the mid-bass, which further increases the driver's Qts with increasing power due to rapid VC heating, which in turns makes the cab increasingly too small.........
If true, then 'stick a sock in it' [a colloquialism used to not so politely tell someone to shut up] so to speak by damping the vent with quite literally a cotton sock since it's big enough, i.e. don't pack it in, just slide it in to partially damp/block it. This should lower tuning a bit to 'bleed off' some of the cab's high Q tuning.
This is confusing for me, the driver gets choked and then you stuff the vent? Doesn't chocking mean more air is needed so the vent needs opening up?
Another more long term solution if this helps is to 'pack' it with drinking straws, fine tuning it by how long they are, so ideally would need to start with longer than vent length straws and shorten as required.
Clear
FWIW, I tightly stretch [layers as required] of scrap speaker grill or expanded knit material over the vent and some folks use coffee machine filters, pieces of felt or open cell foam plugs or similar, so plenty of cheap/free options available to experiment with.
Clear
Still, long term, I assume from memory that a much larger cab is required for best overall performance or dial out more of the mids/HF response with the filter and/or listen as far off axis as it takes th get the mids on down sounding 'right', then increasing the cap value as required to 'lift up' the extreme HF to match.
Yes the cab needs to bigger that is very clear now, but inpatient as I am I went on with the finish of the cabinet and it would be a shame to throw it away. What I do have in mind is to get another driver which has a beter match with the cabinet but that needs funding. (I know this is reverse engineering)
Hi all,
Well I am not quite there yet sound wise... But I thought in the meanwhile I could make the aluminum rings which I talked about...
I wanted a tight fit... the rings was 0.5mm to wide and the wood was painted so in short it did fit. It took a long time to get them to fit, during the long process I scratched the cabinet and put a Stanley knife in my finger.. Although I was very mad on myself I do like the result
And off course it sounds way better hahaha. Well one down, one to go..
sorry for low quality picture..my phone had better days..
R.
Well I am not quite there yet sound wise... But I thought in the meanwhile I could make the aluminum rings which I talked about...
I wanted a tight fit... the rings was 0.5mm to wide and the wood was painted so in short it did fit. It took a long time to get them to fit, during the long process I scratched the cabinet and put a Stanley knife in my finger.. Although I was very mad on myself I do like the result
And off course it sounds way better hahaha. Well one down, one to go..
sorry for low quality picture..my phone had better days..
R.
Attachments
Hope you live long enough to finish/enjoy them for awhile.........
Like the 'look', but have to wonder how much 'stronger' reflections might be.
GM
I have a speaker, was made as reflex (60L) with port but Fb was very low and a lot of stuffing and it worked only as a sealed (higher Q) with the same driver. The frequencies where very low and muted to work as intended. I have a philips/vintage FR and one of the best enclosures was aperiodic, as was posted by me at the beginning. The testing was made by old school engineers/audiophiles, from the time, already passed away.
Hi Pepe,
I was very busy... But your post reminded my to write something about where I am now with the project.
I tried many ways to fill the port to create a variovent. I ended up with the "straw" option mentioned earlier.. I don't think it is perfect but overall it sounds ok and there are some moments of surprise/brilliance...
I have to little cousins (with poky fingers...) so a large 12 inch disc on the perfect hight forced me to put something in front of the speakers before it was to late..haha. I think it looks ok.
Where to go now with the project is not clear.
here is a better picture. The black cloth in the port is temporary so I could change out the different port fillings.
R.
I was very busy... But your post reminded my to write something about where I am now with the project.
I tried many ways to fill the port to create a variovent. I ended up with the "straw" option mentioned earlier.. I don't think it is perfect but overall it sounds ok and there are some moments of surprise/brilliance...
I have to little cousins (with poky fingers...) so a large 12 inch disc on the perfect hight forced me to put something in front of the speakers before it was to late..haha. I think it looks ok.
Where to go now with the project is not clear.
here is a better picture. The black cloth in the port is temporary so I could change out the different port fillings.
R.
