Vikash:
In my experience most published curves include 1/3 octave smoothing . . .
By the way, I do my designs with Speaker Workshop too. Pretty good software so long as you have the Wallin Jig 2 built! You know there are some averaged mic .frd files you can load up into SW if you are using that Panasonic electret in your microphone . . . If you had yours professionally calibrated, then that's even better!
Andrew
In my experience most published curves include 1/3 octave smoothing . . .
By the way, I do my designs with Speaker Workshop too. Pretty good software so long as you have the Wallin Jig 2 built! You know there are some averaged mic .frd files you can load up into SW if you are using that Panasonic electret in your microphone . . . If you had yours professionally calibrated, then that's even better!
Andrew
Vikash,
Most published raw-driver curves are 1/3 to 1/6th octave smoothed. If it's for marketing purposes of a finished speaker, 1 octave is good (along with a 60 dB graph...
).
I like to use 1/6th octave for midrange (500-3000 Hz), and use 1/3rd octave elsewhere. It tends to approximate how your ear/hearing sensitivity works, too... If I have to choose, 1/3rd octave is my preference, as it's hard to correct for FR anomalies finer than that with nearly any passive crossover, or even most active EQ/crossover solutions.
Dan Wiggins
Adire Audio®
Most published raw-driver curves are 1/3 to 1/6th octave smoothed. If it's for marketing purposes of a finished speaker, 1 octave is good (along with a 60 dB graph...
).I like to use 1/6th octave for midrange (500-3000 Hz), and use 1/3rd octave elsewhere. It tends to approximate how your ear/hearing sensitivity works, too... If I have to choose, 1/3rd octave is my preference, as it's hard to correct for FR anomalies finer than that with nearly any passive crossover, or even most active EQ/crossover solutions.
Dan Wiggins
Adire Audio®
planet10 said:
How did that go Dave? I've been eyeing the very small aperiodic box on your site's box library for desktop nearfield purposes, but was hoping someone would build it (or something similar) first and report back since I don't have any measuring equipment to do a decent job of tweaking.
The box is a bit small to get an alignment i like the looks of (given factory specs). It looks like tuned to 54 Hz with a bit of resistance in the port should give fairly flat to 50 Hz (without the stuffing there is a 1 dB peak at about 100 Hz (but you may like that). I did the sim at 8.75 litre.
What is a standard port D in GB?
dave
What is a standard port D in GB?
dave
Attachments
I did a few sims with WinISD Pro, and with CSS's T/S-parameters a 55Hz tuning seems to give the best responce in a 8,75l enclosure. However with HobbyHifi's measured T/S I'm getting a +5dB peak at 70Hz with 55Hz tuning. If the tuning is lowered to 35Hz the peak disappears, but the responce is not smooth and group delay is quite high at the lower frequencies.
Basically I've always thought that drivers with high Qts should not be placed in vented enclosures.
Basically I've always thought that drivers with high Qts should not be placed in vented enclosures.
I have some 40.5 and 45mm ports to hand. Both are 121.5mm long.planet10 said:
http://www.maplin.co.uk/Module.aspx?ModuleNo=17602&TabID=2&WorldID=&doy=8m1
The 4.05mm Dia. port seems perfect.
So, I suppose, if your box is large enough, the higher Vas won't be too much of an issue. You'll just have to tune the port lower to match the lower Fs to get rid of the hump.
That is supposing the Hobby Hifi specs are correct.
My box, by the way, is a folded, mass-loaded Voight of sorts. Kind of unusual in that the drivers are near the large end (top) and the port (firing at the floor) is halfway along the line, at the fold.
L=69.5"
Zdriver=4"
Zport=35"
So=56.16sq"
Sl=2.5sq"
density 3.5lb/cuft
Rport=1"
Lport=2.5"
I'll report back when I finally get these things done. Hopefully this week some time.
Max
That is supposing the Hobby Hifi specs are correct.
My box, by the way, is a folded, mass-loaded Voight of sorts. Kind of unusual in that the drivers are near the large end (top) and the port (firing at the floor) is halfway along the line, at the fold.
L=69.5"
Zdriver=4"
Zport=35"
So=56.16sq"
Sl=2.5sq"
density 3.5lb/cuft
Rport=1"
Lport=2.5"
I'll report back when I finally get these things done. Hopefully this week some time.
Max
This may be of interest. Also read Dan Wiggins' post further down in that thread.Landroval said:
I may just make a mock carboard cabinet tuned to 54Hz and see what the measured FR is.
Vikash said:
...further down in that thread I had posted the HobbyHifi and Klang+Ton TSPs
Both are very well respected DIY mags here in Germany, but...
I have the FR125Ss playing in a 12L sealed cabinet, I can't measure them, but I doubt that the f3 is somewhere between 50 and 55 Hz (see the simulation below), from what I'm hearing the f3 is more like in the 70 - 80 Hz area.
I will start experimenting with ports for the 12L enclosure in the next days.
Attachments
Enclosures and Notch
Hi,
I made some measurements on Saturday with a customers reflex cab. So far: 14 liters or 0.5 cu.ft reflex was great (with a 2" port, 4" long).
Notch 1: 0.39mh / 44uF (2x 22) / 12 ohms --> this is for the 1500Hz region
Notch 2: 0.1mh / 4.7uF --> this is for the 7000Hz peak
Now the curve looks good within +/- 2 or 3dB
Regards
Thorsten
P.S. We used the measured parameters of German DIY magazines "HobbyHifi" and "Klang+Ton" (intersection of both results)
Hi,
I made some measurements on Saturday with a customers reflex cab. So far: 14 liters or 0.5 cu.ft reflex was great (with a 2" port, 4" long).
Notch 1: 0.39mh / 44uF (2x 22) / 12 ohms --> this is for the 1500Hz region
Notch 2: 0.1mh / 4.7uF --> this is for the 7000Hz peak
Now the curve looks good within +/- 2 or 3dB
Regards
Thorsten
P.S. We used the measured parameters of German DIY magazines "HobbyHifi" and "Klang+Ton" (intersection of both results)
Tsp
To get the plot out of my measurement prog will take a while. Here are the TSP of "Hobby Hifi" (Klang + Ton was very close):
FR125S
Fs: 44,8 Hz
Qms: 3,6
Qes: 0,66
Qts: 0,56
Vas: 8,7 L
Cms: 2,4 mm/N
Rms: 0,41 kg/s
Sd: 50 qcm
Xmax: 6mm
Re: 7,1 Ohms
Le: 0,39 mH
BL: 4 N/A
Mms: 5,3 grams
WR125S
Fs: 59,8 Hz
Qms: 5,7
Qes: 0,96
Qts: 0,62
Cms: 1,6 mm/N
Rms: 0,29 kg/s
Vas: 5,8L
Sd: 50 qcm
Xmax: 6mm
Re: 7,2 Ohms
Le: 0,71 mH
BL: 4,1 N/A
Mms: 4,4grams
WR125ST
Fs: 67,8 Hz
Qms: 5,7
Qes: 0,89
Qts: 0,77
Vas: 4,4 L
Cms: 1,3 mm/N
Rms: 0,31 kg/s
Sd: 50 qcm
Xmax: 6mm
Re: 16,2 Ohms
Le: 1,22 mH
BL: 5,7 N/A
Mms: 4,2 grams
I can't scan the whole article due to copyright laws, sorry!
Regards
Thorsten
To get the plot out of my measurement prog will take a while. Here are the TSP of "Hobby Hifi" (Klang + Ton was very close):
FR125S
Fs: 44,8 Hz
Qms: 3,6
Qes: 0,66
Qts: 0,56
Vas: 8,7 L
Cms: 2,4 mm/N
Rms: 0,41 kg/s
Sd: 50 qcm
Xmax: 6mm
Re: 7,1 Ohms
Le: 0,39 mH
BL: 4 N/A
Mms: 5,3 grams
WR125S
Fs: 59,8 Hz
Qms: 5,7
Qes: 0,96
Qts: 0,62
Cms: 1,6 mm/N
Rms: 0,29 kg/s
Vas: 5,8L
Sd: 50 qcm
Xmax: 6mm
Re: 7,2 Ohms
Le: 0,71 mH
BL: 4,1 N/A
Mms: 4,4grams
WR125ST
Fs: 67,8 Hz
Qms: 5,7
Qes: 0,89
Qts: 0,77
Vas: 4,4 L
Cms: 1,3 mm/N
Rms: 0,31 kg/s
Sd: 50 qcm
Xmax: 6mm
Re: 16,2 Ohms
Le: 1,22 mH
BL: 5,7 N/A
Mms: 4,2 grams
I can't scan the whole article due to copyright laws, sorry!
Regards
Thorsten
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