You can share volume, but a larger speaker generally would be better off with more volume than the smaller speaker.
The differing size speakers will introduce a sort of “drone cone”, or passive radiator aspect into the design, tuning won’t be straight forward.
Since both speakers have the same magnet structure, displacement is probably more on the larger speaker, it should use a larger port volume than the smaller speaker.
Using the same gross volume, you can split up the the two speakers with a center divider, and tune both portions to 25 Hz with a port for each chamber.
Using separate chambers will reduce distortion, even in cabinets using the same type of speaker, more so with different size speakers.
You are welcome.
By the way, I did put 12" and 15" speakers in the same chamber back around 1972, let's just say that I learned from my mistakes
.
A link with a study full range + woofer :
http://www.fortunecity.com/rivendell/xentar/1179/theory/dddllqd/dddllqd.html
http://www.fortunecity.com/rivendell/xentar/1179/theory/dddllqd/dddllqd.html
Having seen them, stuck my arm in the port, and touched both woofers (Focal), I'd say you were incorrect. Maybe they have changed it for the newer version, I saw the original.
The Speakerlab Model 7 was also this way.
http://myweb.cableone.net/cpwoods/Audiokarma/Model7.jpg
The Speakerlab Model 7 was also this way.
An externally hosted image should be here but it was not working when we last tested it.
http://myweb.cableone.net/cpwoods/Audiokarma/Model7.jpg
Last edited:
You would think so, but these two examples didn't seem to have a problem. I wonder what the driver parameters look like?
These two drivers have similar Vas and Fs, I wonder how they would work together?
MAGNUM® 15HO
Thiele-Small Parameters
Resonant Frequency (fs)
Impedance (Re)
Coil Inductance (Le)
Electromagnetic Q (Qes)
Mechanical Q (Qms)
Total Q (Qts)
Compliance Equivalent Volume (Vas)
Peak Diaphragm Displacement Volume (Vd)
Mechanical Compliance of Suspension (Cms)
BL Product (BL)
Diaphragm Mass inc. Airload (Mms)
Equiv. Resistance of Mechanical
Suspension Loss (Rms)
Efficiency Bandwidth Product (EBP)
Voice Coil Overhang (Xmax)
Surface Area of Cone (Sd)
Impedance at Resonance (Zmax)
Maximum Mechanical Limit (Xmech)
15", 381mm
8 ohm
650Wrms / 1,300Wpeak
33Hz
35Hz - 1.5kHz
98 dB
109oz., 3.1 kg.
0.375", 9.5mm
4", 101.6mm
56 - 112 liters
2 - 4 cu. ft.
4.5 liters, 0.159 cu. ft.
15.21", 386.4mm
14.0", 355.5mm
fitted as standard
fitted as standard
0.275", 7mm
14.56", 369.9mm
6.42", 163mm
26lbs., 11.8kg.
33Hz
6.3 ohm
1.28mH
0.28
7.48
0.27
241 liters
8.51 cu. ft.
411cc
0.2343mm/N
21.28 T-M
98.1 grams
2.7354N*sec/M
116.6
4.8mm
856cm2
175 ohm
28.58mm
MAGNUM® 18LF
Thiele-Small Parameters
Resonant Frequency (fs)
Impedance (Re)
Coil Inductance (Le)
Electromagnetic Q (Qes)
Mechanical Q (Qms)
Total Q (Qts)
Compliance Equivalent Volume (Vas)
Peak Diaphragm Displacement Volume (Vd)
Mechanical Compliance of Suspension (Cms)
BL Product (BL)
Diaphragm Mass inc. Airload (Mms)
Equiv. Resistance of Mechanical
Suspension Loss (Rms)
Efficiency Bandwidth Product (EBP)
Voice Coil Overhang (Xmax)
Surface Area of Cone (Sd)
Impedance at Resonance (Zmax)
Maximum Mechanical Limit (Xmech)
18", 457.2mm
8 ohm
800Wrms / 1,600Wpeak
32Hz
28Hz - 1.6kHz
95 dB
109oz., 3.1 kg.
0.375", 9.5mm
4", 101.6mm
112 - 280 liters
4 - 10 cu. ft.
7.5 liters, 0.27 cu. ft.
18", 457.2mm
16.56", 420mm
fitted as standard
fitted as standard
0.25", 6.4mm
17.25", 438.2mm
8.15", 207mm
29lbs., 13.1kg.
32Hz
6.1W
2.65mH
0.33
7.33
0.32
254 liters
8.97 cu. ft.
754cc
0.1258mm/N
27.23 T-M
200 grams
5.4365N*sec/M
96.2
6.4mm
1188cm2
185 ohm
31.75mm
These two drivers have similar Vas and Fs, I wonder how they would work together?
MAGNUM® 15HO
Thiele-Small Parameters
Resonant Frequency (fs)
Impedance (Re)
Coil Inductance (Le)
Electromagnetic Q (Qes)
Mechanical Q (Qms)
Total Q (Qts)
Compliance Equivalent Volume (Vas)
Peak Diaphragm Displacement Volume (Vd)
Mechanical Compliance of Suspension (Cms)
BL Product (BL)
Diaphragm Mass inc. Airload (Mms)
Equiv. Resistance of Mechanical
Suspension Loss (Rms)
Efficiency Bandwidth Product (EBP)
Voice Coil Overhang (Xmax)
Surface Area of Cone (Sd)
Impedance at Resonance (Zmax)
Maximum Mechanical Limit (Xmech)
15", 381mm
8 ohm
650Wrms / 1,300Wpeak
33Hz
35Hz - 1.5kHz
98 dB
109oz., 3.1 kg.
0.375", 9.5mm
4", 101.6mm
56 - 112 liters
2 - 4 cu. ft.
4.5 liters, 0.159 cu. ft.
15.21", 386.4mm
14.0", 355.5mm
fitted as standard
fitted as standard
0.275", 7mm
14.56", 369.9mm
6.42", 163mm
26lbs., 11.8kg.
33Hz
6.3 ohm
1.28mH
0.28
7.48
0.27
241 liters
8.51 cu. ft.
411cc
0.2343mm/N
21.28 T-M
98.1 grams
2.7354N*sec/M
116.6
4.8mm
856cm2
175 ohm
28.58mm
MAGNUM® 18LF
Thiele-Small Parameters
Resonant Frequency (fs)
Impedance (Re)
Coil Inductance (Le)
Electromagnetic Q (Qes)
Mechanical Q (Qms)
Total Q (Qts)
Compliance Equivalent Volume (Vas)
Peak Diaphragm Displacement Volume (Vd)
Mechanical Compliance of Suspension (Cms)
BL Product (BL)
Diaphragm Mass inc. Airload (Mms)
Equiv. Resistance of Mechanical
Suspension Loss (Rms)
Efficiency Bandwidth Product (EBP)
Voice Coil Overhang (Xmax)
Surface Area of Cone (Sd)
Impedance at Resonance (Zmax)
Maximum Mechanical Limit (Xmech)
18", 457.2mm
8 ohm
800Wrms / 1,600Wpeak
32Hz
28Hz - 1.6kHz
95 dB
109oz., 3.1 kg.
0.375", 9.5mm
4", 101.6mm
112 - 280 liters
4 - 10 cu. ft.
7.5 liters, 0.27 cu. ft.
18", 457.2mm
16.56", 420mm
fitted as standard
fitted as standard
0.25", 6.4mm
17.25", 438.2mm
8.15", 207mm
29lbs., 13.1kg.
32Hz
6.1W
2.65mH
0.33
7.33
0.32
254 liters
8.97 cu. ft.
754cc
0.1258mm/N
27.23 T-M
200 grams
5.4365N*sec/M
96.2
6.4mm
1188cm2
185 ohm
31.75mm
Last edited:
Dennis,
I used the EV 8HD horn and T-35 tweeters a few years after putting 12 and 15 inch speakers in the same chamber.
If you don’t think a T-35 and 8HD as used in the The Speakerlab Model 7 have problems, then different speakers sharing the same chamber also would not be a problem
.One man’s meat is another man’s poison...
Art
Hi domtweaker, some time since I heard from you.
How are things, and how did it go with the 10" AT and the speaker you were to design using it? -Is this the same AT + an even bigger one ?? :-O
- If so AWESOME driver setup!! should be able to get to the WA MAXX level...
My 2c on the topic of two woofers with same or slightly different size:
Two woofers in a speaker leaves two good possibilies as I see it;
1) big shared chamber -ported
2) one big with port and one small chamber with adjustable acoustic vent in between the two(which can be adjusted and even closed).
If 1) is chosen its straight forward; -simulate both woofers, find the volume each prefer and sum these to make a qualified guess about the prefered size of the shared chamber. The exact behavior of each woofer is difficult to predict, but it is most likely a purely academic discussion as you are interested in the summarized output which will depend on your port tuning, cabinet size and internal damping... As said WA does double woofer/one shared chamber designs and they works quite well (to say the least ;-) ), so I think you´ll be fine with that approach too. Don´t be intimidated by the confusing arguments for and against
If option 2) is chosen it is a bit more up to your fidling as you´ll have a vent between the chambers to tune too. The idea here is to have a quite small chamber for the little woofer (if the 10" is the AT we talked about earlier this could be 25-40L) to get a "fast" response that rolls off (which is adjusted by the flow of the vent). The the larger woofer gets a rather big enclosure with port to go low. This enables you to adjust the roll off of the woofers both by vent and port to get what you want
Option one will get most low low low end where option two will mean a bit smaller enclosure and enables more possibilities to adjustment the roll off to what you prefer. It will probably also get you better midbass due to the small chamber and the adjustment possibilites
If the speaker is for the room you told me about, then option two will enable you to tune the low end better as you may get into problems with too much low end and thereby a presentation that seem slow -not speedy
cheers,
How are things, and how did it go with the 10" AT and the speaker you were to design using it? -Is this the same AT + an even bigger one ?? :-O
- If so AWESOME driver setup!! should be able to get to the WA MAXX level...
My 2c on the topic of two woofers with same or slightly different size:
Two woofers in a speaker leaves two good possibilies as I see it;
1) big shared chamber -ported
2) one big with port and one small chamber with adjustable acoustic vent in between the two(which can be adjusted and even closed).
If 1) is chosen its straight forward; -simulate both woofers, find the volume each prefer and sum these to make a qualified guess about the prefered size of the shared chamber. The exact behavior of each woofer is difficult to predict, but it is most likely a purely academic discussion as you are interested in the summarized output which will depend on your port tuning, cabinet size and internal damping... As said WA does double woofer/one shared chamber designs and they works quite well (to say the least ;-) ), so I think you´ll be fine with that approach too. Don´t be intimidated by the confusing arguments for and against
If option 2) is chosen it is a bit more up to your fidling as you´ll have a vent between the chambers to tune too. The idea here is to have a quite small chamber for the little woofer (if the 10" is the AT we talked about earlier this could be 25-40L) to get a "fast" response that rolls off (which is adjusted by the flow of the vent). The the larger woofer gets a rather big enclosure with port to go low. This enables you to adjust the roll off of the woofers both by vent and port to get what you want
Option one will get most low low low end where option two will mean a bit smaller enclosure and enables more possibilities to adjustment the roll off to what you prefer. It will probably also get you better midbass due to the small chamber and the adjustment possibilites
If the speaker is for the room you told me about, then option two will enable you to tune the low end better as you may get into problems with too much low end and thereby a presentation that seem slow -not speedy
cheers,
Thank you again,
Yes its the same 10 AT , However the 12 AT is an 8 ohm version ( since active ampl. should be okay that way ).
If I can not get another 10 " I will have to use a 12 " ( I found already ) .
They are diff imp , same motor structures though . close sensitivitiy too . 93 each .
They will be driven with sep amps .
I just may try that with the 12 AT .
My first choice would be a double 10" as the box is smaller indeed.
Best
Yes its the same 10 AT , However the 12 AT is an 8 ohm version ( since active ampl. should be okay that way ).
If I can not get another 10 " I will have to use a 12 " ( I found already ) .
They are diff imp , same motor structures though . close sensitivitiy too . 93 each .
They will be driven with sep amps .
I just may try that with the 12 AT .
My first choice would be a double 10" as the box is smaller indeed.
Best
Stupid question, but do you really NEED more than the 10" can deliver?
Have you tried it properly yet?
Headroom is good but keeping it simple (at first at least) usually pays off
If your using 8ohm and 4ohm and separate amps I´d go for separate enclosures (due to possible phase and timing differences) with a hole diameter of around 8cm between the enclosures stuffed with damping material; try using less or more as you try different lenghts of the port for the larger woofer.
If you go for all separate cabinets then then look at the JM lab larger utopia´s where they use an 11" "kick bass" and a 15" low end `pump´ from 50Hz and down as I remember... Different drivers, different cabinets, different purposes, or one cabinet same purpose = low end
If it were two 8ohm´s you wouldn´t need separate amps, and as you already have the 10" 4ohm, why all the extra trouble? Personally I would keep the 10" 93dB/4ohm! beast unless you´ll run a home disco or exercise organ shaking...
Have you tried it properly yet?
Headroom is good but keeping it simple (at first at least) usually pays off
If your using 8ohm and 4ohm and separate amps I´d go for separate enclosures (due to possible phase and timing differences) with a hole diameter of around 8cm between the enclosures stuffed with damping material; try using less or more as you try different lenghts of the port for the larger woofer.
If you go for all separate cabinets then then look at the JM lab larger utopia´s where they use an 11" "kick bass" and a 15" low end `pump´ from 50Hz and down as I remember... Different drivers, different cabinets, different purposes, or one cabinet same purpose = low end
If it were two 8ohm´s you wouldn´t need separate amps, and as you already have the 10" 4ohm, why all the extra trouble? Personally I would keep the 10" 93dB/4ohm! beast unless you´ll run a home disco or exercise organ shaking...
Last edited:
No I have not tried it properly .
I m downsizing from 4 15 " woofers to 2 10s or 10 and 12 set up .
Sometimes I like to drop the needle on the Pink Floyd " The Wall " and crank it up .
Mostly jazz listening though .
I Listen to alot of drums too .
I really can not imagine two 10 " AT giving me what I want .
I will know very soon if I can have two more 10 s and that would make me smile.
Having built few sets of speakers with multiple woofers I really believe that more is better.
If I could afford it would be great to use 4 10 " AT per side and 1 8" midbass + midrange and tweeter.
They sound more dynamic and less distortion for sure.
I did some experiments and dual woofers are better to my ear. Feel tighter too .
Only if money were no object I once heard 8 10 " bass drivers and it was unreal how clean and tight the bass was .
I will know soon what happens
I m downsizing from 4 15 " woofers to 2 10s or 10 and 12 set up .
Sometimes I like to drop the needle on the Pink Floyd " The Wall " and crank it up .
Mostly jazz listening though .
I Listen to alot of drums too .
I really can not imagine two 10 " AT giving me what I want .
I will know very soon if I can have two more 10 s and that would make me smile.
Having built few sets of speakers with multiple woofers I really believe that more is better.
If I could afford it would be great to use 4 10 " AT per side and 1 8" midbass + midrange and tweeter.
They sound more dynamic and less distortion for sure.
I did some experiments and dual woofers are better to my ear. Feel tighter too .
Only if money were no object I once heard 8 10 " bass drivers and it was unreal how clean and tight the bass was .
I will know soon what happens
"If you don’t think a T-35 and 8HD as used in the The Speakerlab Model 7 have problems, then different speakers sharing the same chamber also would not be a problem"
I'm not a fan of the T35 or the 8HD either, and am amused that you could somehow reason some conclusion about the woofer loading from the mid and HF drivers.
I don't know what parameters to look for in making such a box, and that's why I asked. I also don't know how to simulate such an enclosure either, but I do know of two commercially available speakers that used such loading. Aside for the $80K price tag on the Wilson Audio, I heard nothing objectionable.
Oh, Yamaha also made a PA speaker with a 10 and a 12. Before Art has a chance to point out that these were less than stellar performers, let me point out that the handful of cheap cone tweeters in this box was not the best solution for the highs.
http://farm3.static.flickr.com/2467/5806334617_2afbf82fed_b.jpg
I'm not a fan of the T35 or the 8HD either, and am amused that you could somehow reason some conclusion about the woofer loading from the mid and HF drivers.
I don't know what parameters to look for in making such a box, and that's why I asked. I also don't know how to simulate such an enclosure either, but I do know of two commercially available speakers that used such loading. Aside for the $80K price tag on the Wilson Audio, I heard nothing objectionable.
Oh, Yamaha also made a PA speaker with a 10 and a 12. Before Art has a chance to point out that these were less than stellar performers, let me point out that the handful of cheap cone tweeters in this box was not the best solution for the highs.
http://farm3.static.flickr.com/2467/5806334617_2afbf82fed_b.jpg
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.