That 15PR300 is new to me? Could be interesting?
Troels was the one who put me onto the PR400
http://www.troelsgravesen.dk/OBL-15.htm
Unfortunately things are often vastly more expensive in Australia than they should be, I was very fortunate to get a bargain, I actually got them for less than that price.......................................
But anyway, I digress!!!! 😆
I do appreciate the synergy of using a similar woofer to help out the full ranger. Elegant.
Troels was the one who put me onto the PR400
http://www.troelsgravesen.dk/OBL-15.htm
Unfortunately things are often vastly more expensive in Australia than they should be, I was very fortunate to get a bargain, I actually got them for less than that price.......................................
But anyway, I digress!!!! 😆
I do appreciate the synergy of using a similar woofer to help out the full ranger. Elegant.
Beginner here. I'm considering using this driver to built a cheap 5.1 system for my son. Most people here seem to use horns, transmission lines etc to get some bass out. What if I just want to use it as a "sat" speaker, sealed box with a 2nd order high pass, which would be simpler to construct than ported etc. - would it be possible to build something relatively compact, and use a high pass of no higher than 120 Hz?
Due to placement, I have plenty of wall space available but not much depth. So the box could be relatively wide and tall (to an extent), but needs to be shallow. What would be the least advisable cabinet depth? I assume the driver needs room to "breathe"?
Thanks.
Due to placement, I have plenty of wall space available but not much depth. So the box could be relatively wide and tall (to an extent), but needs to be shallow. What would be the least advisable cabinet depth? I assume the driver needs room to "breathe"?
Thanks.
i have reduce the polyester to 40gr but we don't have all the same polyester.
to macci in my opinion DDVP20 is a too big bow for what it bring in bass for instrumental music it can be a good a idea but in any case if you listen modern music you need a sub.... your idea to make sattelite is good.... what about a blenda box( bowl) to have less diffraction and better spatialisation...
to macci in my opinion DDVP20 is a too big bow for what it bring in bass for instrumental music it can be a good a idea but in any case if you listen modern music you need a sub.... your idea to make sattelite is good.... what about a blenda box( bowl) to have less diffraction and better spatialisation...
@Pierrick59
You will then need two big blenda boxes.
On another note, what amplifier are you using? That can have quite an impact. In my experience, fullrange speakers sound better with an amp that has somewhat higher output impedance (3-15 ohms).
If you are using a typical "transistor" amp with the fullranger, it can sound " thin".
For a test, try to find a high power 10 ohm resistor, and put it in series, between the amplifier and a speaker (+ lead).
Then report back 😉
You will then need two big blenda boxes.
On another note, what amplifier are you using? That can have quite an impact. In my experience, fullrange speakers sound better with an amp that has somewhat higher output impedance (3-15 ohms).
If you are using a typical "transistor" amp with the fullranger, it can sound " thin".
For a test, try to find a high power 10 ohm resistor, and put it in series, between the amplifier and a speaker (+ lead).
Then report back 😉
Indeed! SET tubes, other tube designs with variable DF tone controls or just a 25 - 50 ohm pot to dial it in in-room and replace with a fixed (adjustable) power resistor (ideally a bank using small 1% resistors to get the desired power, heat specs).
If you have five 20cm SB Acoustics drivers I would use them fullrange in standing bass reflex boxes, close to the walls or even corner placement.
Then you can omit easily a subwoofer.
Or you put them in small well stuffed closed boxes as you described. Maybe wall mounted. They are filtered by the amplifier. No need for extra high pass. But then you need a potent subwoofer.
Some modern surround amps have Auto EQ function!
Then you can omit easily a subwoofer.
Or you put them in small well stuffed closed boxes as you described. Maybe wall mounted. They are filtered by the amplifier. No need for extra high pass. But then you need a potent subwoofer.
Some modern surround amps have Auto EQ function!
I used them in 9.25 deep. Only around 7.5” internal depth and they are fantastic to my ears. You could probably go shallower honestly, especially for less critical HT use. Mine are in about 23L sealed with SB20 woofer in a .5 way (17L). If you wall mount, you can probably get your baffle step comp there and eliminate the second woofer or and baffle stet circuits. Anything under q=1 if fine imo, especially for a driver than isn’t playing that deep
Hi there!
I am planning to design and build my first pair of speakers, and I would like to use the SB20FRPC30-8.
I could make DDVP-20 cabinets, but I like to experiment with new things, and I'm trying to learn how to use Hornresp.
I did a simulation for a cabinet design quite similar to the DDVP-20, a little narrower (20cm internal) and deeper (36cm internal), with SB20FRPC30-8's parameters.
Not being familiar with Hornresp and TQWT, I don't know how to interpret some results, and some graphs look quite chaotic, I don't know if this is normal or not.
Concerning the filling, I put a fairly large quantity but perhaps in practice it would be necessary to have less...
Could you please tell me if this looks like correct results or not?
I am planning to design and build my first pair of speakers, and I would like to use the SB20FRPC30-8.
I could make DDVP-20 cabinets, but I like to experiment with new things, and I'm trying to learn how to use Hornresp.
I did a simulation for a cabinet design quite similar to the DDVP-20, a little narrower (20cm internal) and deeper (36cm internal), with SB20FRPC30-8's parameters.
Not being familiar with Hornresp and TQWT, I don't know how to interpret some results, and some graphs look quite chaotic, I don't know if this is normal or not.
Concerning the filling, I put a fairly large quantity but perhaps in practice it would be necessary to have less...
Could you please tell me if this looks like correct results or not?
I finally built my monster.
SB20 in a 30L aperiodic box with a LCR correction network in series with the driver.
What can I say, the transparency, timing, ambience is amazing.
Before that I had this driver in an OB with a 15" woofer, and it is great, but this, with all its shortcomings is just unreal.
Porcupine Tree, In Absentia, is a great test CD.
SB20 in a 30L aperiodic box with a LCR correction network in series with the driver.
What can I say, the transparency, timing, ambience is amazing.
Before that I had this driver in an OB with a 15" woofer, and it is great, but this, with all its shortcomings is just unreal.
Porcupine Tree, In Absentia, is a great test CD.
Attachments
congrats on finishing your project!
how do you find the bass? satisfying?
could you plz post the details?
how do you find the bass? satisfying?
I used Basta, the good old Basta, for all the simulation.
Thank you Svante!
The LCR network is:
C 4.7uF
L 1.8mH
R 4.7R / 5W
All components in parallel and then this whole lot in series with the positive.
As I had no 4.7R I used 3.9R and the range around 800Hz - 1kHz is a bit hotter than I want it to be. Verified with a small Android app called Spectroid.
The bass is great. Not as deep as from the 15" woofers, but deep enough, tight, very satisfying. And very much in synergy with the rest.
Porcupine Tree, In Absentia, track 8 & 11 are perfect for such evaluation.
All this is a compromise of course, but everything in speaker design is a compromise.
Will need to buy another pair of SB20 to fit back to my OB which you see behind the Aperiodic boxes.
Thank you Svante!
The LCR network is:
C 4.7uF
L 1.8mH
R 4.7R / 5W
All components in parallel and then this whole lot in series with the positive.
As I had no 4.7R I used 3.9R and the range around 800Hz - 1kHz is a bit hotter than I want it to be. Verified with a small Android app called Spectroid.
The bass is great. Not as deep as from the 15" woofers, but deep enough, tight, very satisfying. And very much in synergy with the rest.
Porcupine Tree, In Absentia, track 8 & 11 are perfect for such evaluation.
All this is a compromise of course, but everything in speaker design is a compromise.
Will need to buy another pair of SB20 to fit back to my OB which you see behind the Aperiodic boxes.
I only used a Baffle step circuit for the terrific SB full ranger comprising a .8 inductor and a 1.22 ohms resistor which was quite critical and took some time of trial and error to get the ohms value correct . This was for a 10" baffle width .
Are you happy with the LCR values you mention , if so I will try the same values as you did . regards .
I ordered a pair and put put them in a 35 litre well braced plywood box with 2 inch diameter vent 3.5 inches long as recommended on the Madisound site to give F3 of 45Hz.
They sound pretty terrible.I went through a full range phase about 12 years ago and tried quite a lot.A friend had Goodmans Axiom 80s so I think I have heard some of the best.These are one of the worst.Yes they have better bass than most but that is about the only positive thing I could say about them.The mid and treble sounds really dirty and buzzy and even the imaging which is usually the best thing about wizzer coned drivers is not taht good
I was given a pair of Polk Monitor 8Ts recently and thought they were pretty nasty sounding but even they are a lot better.
These sound a lot better and are half the price.
https://www.altronics.com.au/p/c2000a-redback-200mm-8-inch-8-ohm-10w-dual-cone-pa-speaker/
They sound pretty terrible.I went through a full range phase about 12 years ago and tried quite a lot.A friend had Goodmans Axiom 80s so I think I have heard some of the best.These are one of the worst.Yes they have better bass than most but that is about the only positive thing I could say about them.The mid and treble sounds really dirty and buzzy and even the imaging which is usually the best thing about wizzer coned drivers is not taht good
I was given a pair of Polk Monitor 8Ts recently and thought they were pretty nasty sounding but even they are a lot better.
These sound a lot better and are half the price.
https://www.altronics.com.au/p/c2000a-redback-200mm-8-inch-8-ohm-10w-dual-cone-pa-speaker/
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Yes Leonardo, I'm quite happy with the result. Maybe will need to increase the value of the resistor a bit.
The idea of the correction network was not only to cater for the baffle step but also to lift the highs back to "normal".
Here's what it looks like in Basta with my circuit:
And here's with your values:
I only measure freq. response with a little app, Spectroid, and the result was very close to the predicted one.
The idea of the correction network was not only to cater for the baffle step but also to lift the highs back to "normal".
Here's what it looks like in Basta with my circuit:
And here's with your values:
I only measure freq. response with a little app, Spectroid, and the result was very close to the predicted one.
Attachments
I tried the Altronics years ago and they are cheap & nasty.
@jtgofish I have no intention of arguing with you or anyone else re. sound quality.
Good luck with your Redback.
BTW F3 is pretty meaningless, try F6.
Talking about mid and treble - just mentioning Bass Reflex with this driver gives me shivers.
Put it in an aperiodic box, or MLTL, or even Voigt and let me know what you think then.
Good luck with your Redback.
BTW F3 is pretty meaningless, try F6.
Talking about mid and treble - just mentioning Bass Reflex with this driver gives me shivers.
Put it in an aperiodic box, or MLTL, or even Voigt and let me know what you think then.