Faital 4fe32
I've been listening to the Xki with Faital pro 4fe32 for a couple of days now, and am sorry to say that I'm very disappointed. I really love the 'dispersion' that the K vents give, and the wide 'sweet spot' that results. The speakers themselves totally disappear! I was hoping to use them as TV speakers, but the sound is far too boxy. I've got the boxes lined with 20-25mm high density polyfill, plus the rest of the space filled with loose well teased polyfill, and some felt carpet glued to the inside of the wings.Also the FR drops off at about 85Hz.
Any ideas? are the boxes just too small?
I made a pair of TQWT using the 4fe35 and the mh-audio calculator, which are far better, the volume near double the size. Would I stand a better chance with the karlsonator?
Thanks
I've been listening to the Xki with Faital pro 4fe32 for a couple of days now, and am sorry to say that I'm very disappointed. I really love the 'dispersion' that the K vents give, and the wide 'sweet spot' that results. The speakers themselves totally disappear! I was hoping to use them as TV speakers, but the sound is far too boxy. I've got the boxes lined with 20-25mm high density polyfill, plus the rest of the space filled with loose well teased polyfill, and some felt carpet glued to the inside of the wings.Also the FR drops off at about 85Hz.
Any ideas? are the boxes just too small?
I made a pair of TQWT using the 4fe35 and the mh-audio calculator, which are far better, the volume near double the size. Would I stand a better chance with the karlsonator?
Thanks
Srednivashtar,
Thanks - so looks like bass after baffle step etc is closer to 93dB and -3dB point is 46Hz or so. That's actually a nice performer. The frequencies above 500Hz are not predicted by Akabak well as this is a simplified model to look at bass extension. Should be much smooth and higher reach in reality.
You tuned it quite low - had you tuned it for 55Hz or 60Hz the bass would be closer to 95dB.
Thanks - so looks like bass after baffle step etc is closer to 93dB and -3dB point is 46Hz or so. That's actually a nice performer. The frequencies above 500Hz are not predicted by Akabak well as this is a simplified model to look at bass extension. Should be much smooth and higher reach in reality.
You tuned it quite low - had you tuned it for 55Hz or 60Hz the bass would be closer to 95dB.
Last edited:
Did I model the box for you for 4FE35's? That driver Qts is a bit high for XKi and will do fine in a Karlaonator scaled properly. Try lining inside of K aperture with felt and add ball of polyfill in upper front cavity and see if that reduces boxyness.
Hi, I really don't think I can add any more stuffing, I could change the dense polyfill to industrial quality carpet tiles 
. I'll try that before I abandon them. The boxes are the size in the first post of this thread. I'm totally beginner here, I've spent at least an hour every day for about a year reading, and maybe know 1/2% . The 4FE35's are in boxes taken straight from mh-audio, about 9litre, 430x180x120mm approx. I've now got the gear to test stuff! finding the time is next
. I'll try that before I abandon them. The boxes are the size in the first post of this thread. I'm totally beginner here, I've spent at least an hour every day for about a year reading, and maybe know 1/2% . The 4FE35's are in boxes taken straight from mh-audio, about 9litre, 430x180x120mm approx. I've now got the gear to test stuff! finding the time is next
Yes, I made the duct 30mm instead of 28mm high and shortened it by 5cm compared with the foamboard prototype and initial sim. The idea being that it was easier to reduced the height and lengthen it if necessary to lower than tuning rather than vice versa. Despite this, it has still tuned a bit low.
Hi, I really don't think I can add any more stuffing, I could change the dense polyfill to industrial quality carpet tiles
I'll have a go with Akabak this weekend, but I doubt that I can do any better than xrk971.
My foamcore protypes did sound a bit boxy, but I don't know if this was the carpet offcuts I used to damp them or the foamcore. Stuffing just made them sound dead. I also had trouble with the front chamber and lining it killed the treble too much for my liking. The plywood cabinets sound much better. They are lined with 42oz wool felt underlay. Haven't had time to do any further experimentation with front chamber yet. I am pleased with them - a lot of work, but they sound great.
I will bow to xrk971's superior knowledge on this one.
I can try to model it as best I can in Akabak.
Modelling the cabinet I have built (1), I have tried to incorporate the effects of the air in the corners at A & B as acoustic masses. These increase the effective length of the duct similarly to having 2 corners.
To raise the tuning by shortening the duct significantly (2), the rear end of the duct comes away from the rear wall, removing the corner effect. Instead of an acoustic mass corner correction, I now just add a standard end correcton of 0.3 times the hydraulic diameter (in this case works out to 15mm). So now I am correctng with a corner acoustic mass at B and a 15mm correction at A.
Reducing the duct length from 234mm (my build) to 165mm gives the following response. Depends how much you want to compromise between bass extension and loudness.
I can try to model it as best I can in Akabak.
An externally hosted image should be here but it was not working when we last tested it.
Modelling the cabinet I have built (1), I have tried to incorporate the effects of the air in the corners at A & B as acoustic masses. These increase the effective length of the duct similarly to having 2 corners.
To raise the tuning by shortening the duct significantly (2), the rear end of the duct comes away from the rear wall, removing the corner effect. Instead of an acoustic mass corner correction, I now just add a standard end correcton of 0.3 times the hydraulic diameter (in this case works out to 15mm). So now I am correctng with a corner acoustic mass at B and a 15mm correction at A.
Reducing the duct length from 234mm (my build) to 165mm gives the following response. Depends how much you want to compromise between bass extension and loudness.
An externally hosted image should be here but it was not working when we last tested it.
- thank you much - appreciate the details and simulation - - of course, if a cabinet were made with a removable back, the vent could be empirically adjusted and examined. If it actually peaks with 165mm length, then may not sound so good. I like to see the cabinet with its aperture plate and hear a few impressions of its strengths and ability. Do you feel like the present tuning is in its best compromise position? (I thought perhaps you felt it a bit low -?) The Karlsonator 12 tuned somewhat lower than predicted. I've seen in in my 18 inch RJ cabinets too.
Last edited:
stuffing a reflex cabinet is not very much of a plan. only thing worse you could do would be to stuff the vent. you need to have a clear and open volume or air which can freely resonate so the driver and the vent can couple, this is A resonant system. damp it and you lose that resonant coupling and the benefit of having a vent in the first place. try damping the inside of your cabinet walls with felt and NOT craft felt that is synthetic made of acrylic you need pure wool felt to get the best results.
hey xrk971 - when using your suggested 1772 XKi with 10" drivers do you think it would help to increase the width by an inch? or is the narrow aperture an advantage? I have P-Audio SN10C, Delta10A, and Celestion TF1020, and would of course try Beta10cx to compare with my Karlsonator 12 and 0.62 scale K15
I have several 12" which could use the XKi but guess for now this 3 cubic foot bulk size is nice and worth trying
as it can use a currently produced coax (beta10cx)
P-Audio SN10C
coaxial speaker
diameter in / 10/254 mm
Power RMS (W) 200
resistance (ohms) 8
resonant frequency Fs (Hz) 67.3
Sensitivity 1 W / m (dB) 94
overall quality factor Qts 0,455
equivalent volume Vas (l) 27.2
maximum displacement Xmax (mm) 2.8
Frequency range (Hz) 65-20000
diameter of the coil (in) 2,5
Celestion TF1020
LF Pressed Chassis / Ferrite - TF1020 - Celestion - Guitar, Bass & Pro Audio Speakers
Xmax -2mm/0.08in
Gap depth - 8mm/0.31in
Voice coil winding width - \12mm/0.47in
Small Signal Parameters
D - 0.21m/8.27in
Fs - 60.9Hz
Mms - 30.92g/1.09oz
Mmd -27.27g/0.96oz
Qms -2.853
Qes - 0.361
Qts - 0.32
Re - 5.79Ω
Vas - 37.45lt/1.32ft3
BI -13.79Tm
Cms -0.221mm/N
Rms - 4.15kg/s
Le (at 1kHz) -0.59mH
I have several 12" which could use the XKi but guess for now this 3 cubic foot bulk size is nice and worth trying
as it can use a currently produced coax (beta10cx)
P-Audio SN10C
coaxial speaker
diameter in / 10/254 mm
Power RMS (W) 200
resistance (ohms) 8
resonant frequency Fs (Hz) 67.3
Sensitivity 1 W / m (dB) 94
overall quality factor Qts 0,455
equivalent volume Vas (l) 27.2
maximum displacement Xmax (mm) 2.8
Frequency range (Hz) 65-20000
diameter of the coil (in) 2,5
Celestion TF1020
LF Pressed Chassis / Ferrite - TF1020 - Celestion - Guitar, Bass & Pro Audio Speakers
Xmax -2mm/0.08in
Gap depth - 8mm/0.31in
Voice coil winding width - \12mm/0.47in
Small Signal Parameters
D - 0.21m/8.27in
Fs - 60.9Hz
Mms - 30.92g/1.09oz
Mmd -27.27g/0.96oz
Qms -2.853
Qes - 0.361
Qts - 0.32
Re - 5.79Ω
Vas - 37.45lt/1.32ft3
BI -13.79Tm
Cms -0.221mm/N
Rms - 4.15kg/s
Le (at 1kHz) -0.59mH
Freddi,
If you would like to increase width by an inch that is fine - just adjust depth or height accordingly to preserve volume. Also, decrease slot height to keep same CSA on vent. Making a wider aperture will load the cone less and have less of a K lens effect and more direct radiation. I have to say that the one time Anthony Bisset tried a whizzer cone on a K with the PS-220, it did not sound good. Something about how the HF generated by a whizzer doesn't like to be behind an aperture. A dome tweeter or K tube fine though. So I am just saying, be prepared for a not so great HF signature of whizzer. Have you tried whizzers behind a K aperture before?
I am listening to my coax PA130 XKi right now powered with a Sanwu TDA8932 monoblock this time. I have to say, for $3.22, this amp beats many commercial amps in the $200 to $300 for SQ - not kidding. Super clarity and surprising deep clean bass. Electronic bass and synth kick drums coming through nicely with Enigma tracks playing. I am running mono a lot lately by connecting headphone outputs together via two 4.7k resistors and driving mono amps and single speaker. Great for testing sound of single drivers and amps and not getting distracted by stereo location and setup (or having to have two speakers, or two amps), and for casual listening when you can't sit in stereo sweet spot. This particular TDA8932 gets my vote for *BEST* amp for overall presentation of mids/highs when less than 10 watts (peak and 2-3w RMS) is required.
If you would like to increase width by an inch that is fine - just adjust depth or height accordingly to preserve volume. Also, decrease slot height to keep same CSA on vent. Making a wider aperture will load the cone less and have less of a K lens effect and more direct radiation. I have to say that the one time Anthony Bisset tried a whizzer cone on a K with the PS-220, it did not sound good. Something about how the HF generated by a whizzer doesn't like to be behind an aperture. A dome tweeter or K tube fine though. So I am just saying, be prepared for a not so great HF signature of whizzer. Have you tried whizzers behind a K aperture before?
I am listening to my coax PA130 XKi right now powered with a Sanwu TDA8932 monoblock this time. I have to say, for $3.22, this amp beats many commercial amps in the $200 to $300 for SQ - not kidding. Super clarity and surprising deep clean bass. Electronic bass and synth kick drums coming through nicely with Enigma tracks playing. I am running mono a lot lately by connecting headphone outputs together via two 4.7k resistors and driving mono amps and single speaker. Great for testing sound of single drivers and amps and not getting distracted by stereo location and setup (or having to have two speakers, or two amps), and for casual listening when you can't sit in stereo sweet spot. This particular TDA8932 gets my vote for *BEST* amp for overall presentation of mids/highs when less than 10 watts (peak and 2-3w RMS) is required.
Last edited:
I don't know at the moment which is the best tuning - I am still learning. I don't know whether I would make the duct shorter or not if I were building again. In the thread below, there is some discussion of tuning a bass reflex cabinet - lower tuning improves impulse response at the expense of SPL.
http://www.diyaudio.com/forums/subw...-impulse-response-bass-reflex-enclosures.html
I suspect that the cabinets tuning lower than Akabak simulations is from failure to take into account end corrections and bends in the duct. When I included these corrections, the simulation looks better wrt tuning.
Thanks for info. That is my experience with the XKi.
Ah... will be removing tomorrow, thanks, I was looking at it like the karlsonator, which I took to be a TL, or am I wrong there too? I wish i could find the denim felt over here! Would a trip to a charity shop and picking up a heavy wool coat be worthwhile?
Many thanks
drewan, this company has next day delivery on wool underlay for a reasonable price - I got 2 m2 for 8.99 including delivery. I used 42oz, which is about 11mm thick. I think it is mainly wool with some cotton mixed in.
Wool Felt Carpet Underlay - Multi Rich 42oz
Wool Felt Carpet Underlay - Multi Rich 42oz
That's a good price on felt. Here on USA Amazon free shipping we can get 3.72 sq meters (5ft x 8ft) for $34. All wool though and about 12mm thick. Looks nice, I may have to try this stuff.
http://www.amazon.com/MULTIPLE-Authentic-Industries-Specifiers-rectangle/dp/B005Q83DZ0/
http://www.amazon.com/MULTIPLE-Authentic-Industries-Specifiers-rectangle/dp/B005Q83DZ0/
I've had mainly good experiences with whizzer cones including 12LTA in K12 and Karlsonator 12, SP15 and 15A in K15, BG20 in K12 - with FE206EN in the old Karlsonette as one of my favorites - more load is good too so the original width will work - wonder if it would accommodate SN10C's specs? - how about TF1020 or Delta10A? - am hoping it can take another 10 or two besides Beta10cx (?)
I haven't seen any jute felt in the UK. I guess jute has similar properties to wool with a flatter absorption curve than small diameter fibres such as glass fibre. You can get 100% Cumbrian sheeps wool underlay but it is difficult to buy in quantities less than a roll and is expensive. One of the speaker component webshops I found has it in smaller quantities.
Loudspeaker damping materials for DIY speaker kits.
EDIT
Regarding stuffing of reflex cabinets, I found this article that suggests small diameter fibres such as glass fibre and polyfill which predominantly attenuate at higher frequencies can be used for stuffing without affecting the Q too much.
Volume filling a reflex box
Loudspeaker damping materials for DIY speaker kits.
EDIT
Regarding stuffing of reflex cabinets, I found this article that suggests small diameter fibres such as glass fibre and polyfill which predominantly attenuate at higher frequencies can be used for stuffing without affecting the Q too much.
Volume filling a reflex box
Last edited: