"BR" = "bass reflex" FWIW 1772 sounded nice in a little Karlson type
1772
Audio Nirvana stamped-frame Super 8
1772
An externally hosted image should be here but it was not working when we last tested it.
Audio Nirvana stamped-frame Super 8
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Ok. I have a similar idea for mine.
I Know, what BR means. But I didn't understand what were you asking.
Yes, I designed them myself. Enclosure width and depth was chosen to fit on my subs.
Bob,
didn't you mean 1.5mH||5Ω instead of 1.5mH||15Ω? I don't know almost nothing about passive circuits, but I have calculated 4db BSC for 11" wide baffle and got L=1.5mH and R=4ohm. How do you get 15 ohms?
I used this for my calculations: mh-audio.nl - Home
Try it both ways. See what works for you. When I test a speaker, I use an L-pad in place of the resistor and play with it until I hear what I want. Measure the L-pad and use that value resistor. (I also have a variable inductor. I took a 5mH Erse Super Q and unwound it, then rewound it with taps every 0.5mH 1.0-4.5mH.)
Bob
Bob, I am not sure, if I understand you correctly (I'm not familiar with passive circuits at all). Do you use something like that?
Won't this bring down speaker sensitivity to much?
An externally hosted image should be here but it was not working when we last tested it.
Won't this bring down speaker sensitivity to much?
So I tried this circuit with similar values:
Lbsc 1.5mH
Rbsc 13.2ohm
Rz 4.7ohm
Cz 2.2uF
This is what I get:
The response looks more linear but really sucks out life of music. Enclosure - 40l bass reflex tuned to ~63hz.
In parametric equalizer I used low shelf+3db and high shelf-3db @414hz with Q 0.7 and liked the sound. I would like to get passive circuit close to this. Any suggestions?
Lbsc 1.5mH
Rbsc 13.2ohm
Rz 4.7ohm
Cz 2.2uF
This is what I get:
An externally hosted image should be here but it was not working when we last tested it.
The response looks more linear but really sucks out life of music. Enclosure - 40l bass reflex tuned to ~63hz.
In parametric equalizer I used low shelf+3db and high shelf-3db @414hz with Q 0.7 and liked the sound. I would like to get passive circuit close to this. Any suggestions?
Ah, yes. The problem with a dead flat response. Enter loudness EQ. Seemingly by nature we like to hear a smiley face EQ. Warm, bassy with a bit of tizz. The softer you play the speakers, the more EQ you want to hear.
You see why I advocate digital EQ. You can be much more precise with the EQ, and you don't have to solder in new parts to change it. You don't want a flat response, you want a smooth response. The lowest point of the FR should be ~2kHz -- the BBC dip.
BTW, I thought I answered you question about the filter reducing SPL, but I guess it got lost. Yes, a BSC filter reduces the ultimate SPL. Manufacturers tend to use the 1kHz FR level as the published "efficiency". It's often a lie. The real sensitivity it the ~100Hz response. Using your uncalibrated no filter FR, The 1kHz level is 9odB and the 100Hz is 85dB. That is a drop of 5dB and that is very normal.
Bob
You see why I advocate digital EQ. You can be much more precise with the EQ, and you don't have to solder in new parts to change it. You don't want a flat response, you want a smooth response. The lowest point of the FR should be ~2kHz -- the BBC dip.
BTW, I thought I answered you question about the filter reducing SPL, but I guess it got lost. Yes, a BSC filter reduces the ultimate SPL. Manufacturers tend to use the 1kHz FR level as the published "efficiency". It's often a lie. The real sensitivity it the ~100Hz response. Using your uncalibrated no filter FR, The 1kHz level is 9odB and the 100Hz is 85dB. That is a drop of 5dB and that is very normal.
Bob
Bob, thanks for your response! I have simulated this passive circuit situation in the parametric EQ. Changed Q values, reduced BSC level a bit and now the sound is much better. I will try to change resistor values in passive filter and see if some improvements can be made.
Maybe someone can suggest a measurement software where EQ before measurements could be applied? I want to see response I like so I can try to make passive filter as close as possible.
Maybe someone can suggest a measurement software where EQ before measurements could be applied? I want to see response I like so I can try to make passive filter as close as possible.
Holmimpulse is an excellent program to do measurements with. Get a good mic or make one from a Panasonic WM61A capsule. It need not be absolute calibrated but just flat in response.
1772's horn loaded
Just for kicks, I loaded my pair in some vintage 1939 Jensen Exponential horns. As far a back chamber, it's simply a 9 inch by 18 inch long cardboard tube loaded with acoustic material. While no means "state-of-the-art" they do some things that are simply amazing. I sure can hear the effect of the horn, so I'd say an ORIS type would do much, much better. Even so, the sound quality is very robust and rich, by NO MEANS is it as lean as when I tried these in an open baffle. I mean night and day differences. The highs are quite a bit subdued, though. I must stress, they are far from perfect, but what they get right, they get soooooo right. Some of my fellow club members insist it's all about the round horn.
Just for kicks, I loaded my pair in some vintage 1939 Jensen Exponential horns. As far a back chamber, it's simply a 9 inch by 18 inch long cardboard tube loaded with acoustic material. While no means "state-of-the-art" they do some things that are simply amazing. I sure can hear the effect of the horn, so I'd say an ORIS type would do much, much better. Even so, the sound quality is very robust and rich, by NO MEANS is it as lean as when I tried these in an open baffle. I mean night and day differences. The highs are quite a bit subdued, though. I must stress, they are far from perfect, but what they get right, they get soooooo right. Some of my fellow club members insist it's all about the round horn.
Attachments
W8-1772 open baffle
This is my second speaker building project and the best sounding pair of speakers I ever heard. The baffle plan comes from Troels OBL-11. Instead of his midrange and tweeter combo I decided to try W8-1772 and go fully active.
Works without BSC if LPF 2nd order + HPF 1st order @175hz used. I got better results using lower crossover point (80hz LPF + 115hz HPF both 4th order) and adding -5db BSC to W8-1772 @230hz. I also use -5db high-shelf for bass driver @60hz + -3db@1500hz and -3db@7000hz high-shelf for W8-1772.
Measured right speaker from listening position:
This is my second speaker building project and the best sounding pair of speakers I ever heard. The baffle plan comes from Troels OBL-11. Instead of his midrange and tweeter combo I decided to try W8-1772 and go fully active.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Works without BSC if LPF 2nd order + HPF 1st order @175hz used. I got better results using lower crossover point (80hz LPF + 115hz HPF both 4th order) and adding -5db BSC to W8-1772 @230hz. I also use -5db high-shelf for bass driver @60hz + -3db@1500hz and -3db@7000hz high-shelf for W8-1772.
Measured right speaker from listening position:
An externally hosted image should be here but it was not working when we last tested it.
Darkheart,
Wonderful looking and sounding build there. Congratulations!
I don't think I have ever seen such a nice frequency response curve flat from 30 Hz to 20 kHz. How is the spatial presentation and imaging? Is it tolerant to moving outside of sweet spot as I hear 8 in full range drivers can have 'beam like' HF. Also, how are you implementing all your filtering? Is that all done via mini DSP and biamping? That would be a pain to do all that passively.
Great job !
Wonderful looking and sounding build there. Congratulations!
I don't think I have ever seen such a nice frequency response curve flat from 30 Hz to 20 kHz. How is the spatial presentation and imaging? Is it tolerant to moving outside of sweet spot as I hear 8 in full range drivers can have 'beam like' HF. Also, how are you implementing all your filtering? Is that all done via mini DSP and biamping? That would be a pain to do all that passively.
Great job !
Thanks! 
Imaging and spatial presentation is quite good, but not perfect. They don't disappear like narrow baffles, but it's not my priority. There is some beaming, of course, if I move more then 0,5m too each side, but usually I don't. The off-axis response of W8-1772 is relatively good.
All filtering is done via JRiver's Media Center in-built DSP. My current source is Asus Xonar Essence ST + Xonar H6, which feeds two stereo amps (NAD C355BEE for bass and NAD C326BEE for widerange).
Forgot about one more filter - at 250hz there is -5db notch filter for baffle hump.
Imaging and spatial presentation is quite good, but not perfect. They don't disappear like narrow baffles, but it's not my priority. There is some beaming, of course, if I move more then 0,5m too each side, but usually I don't.
The off-axis response of W8-1772 is relatively good. All filtering is done via JRiver's Media Center in-built DSP. My current source is Asus Xonar Essence ST + Xonar H6, which feeds two stereo amps (NAD C355BEE for bass and NAD C326BEE for widerange).
Forgot about one more filter - at 250hz there is -5db notch filter for baffle hump.
The 1772 and the Alpairs are apples and oranges. I don't have a pair of 1772's on hand at the moment for a direct comparison, so this is from memory.
The W8-1772 is a heavyweight. It will fill a fairly large room with a lot of sound and it has a both a decent top and bottom. In a decent cabinet, the 1772 will get into the low 30's with authority. The dispersion at the top is good enough that a tweeter in not required. It remains my favorite 8" driver. Does everything a FF225WK plus a FT17H can do.
Alpairs are a different animal. They are about finesse. You need to sit down with a pair and play some transparent music. Two cuts that pretty much say it all are Alison Krauss "Forget About It" and Fleetwood Mac "Never Going Back Again". I am listening to the new A10M.3's and I am getting the impression that they are A7.3's on steroids. You will hear that the Ailpairs are intolerant of poor electronics (usually intended to mean anything not tubes). I don't really think so, as they sound wonderful on T-amps. However, they are death to bad recordings. Don't bother playing anything mastered for pop radio this century. You will not enjoy the results.
Bob
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