Hi guys,
I need your help, i'm currently designing this cabinet, i already bought all the speakers except the 12" woofer on the side.
I'm using two HDS PPB 134 and one Fountek NeoCD2.0 for the tweeter.
The distance between the acoustic center and the midwoofer is about 127mm, i would like to design the passive filter using a 3rd or 4th BW or LR slope.
I was thinking to cross the 12" at 80 and the midwoofers at 2.5K but i'm not sure.
I would like to know which crossover frequency to choose?
I'm searching a good sounding 12" woofer with a sensivity of 92 93 db.
Thanks in advance for your help.
Sabry
I need your help, i'm currently designing this cabinet, i already bought all the speakers except the 12" woofer on the side.
I'm using two HDS PPB 134 and one Fountek NeoCD2.0 for the tweeter.
The distance between the acoustic center and the midwoofer is about 127mm, i would like to design the passive filter using a 3rd or 4th BW or LR slope.
I was thinking to cross the 12" at 80 and the midwoofers at 2.5K but i'm not sure.
I would like to know which crossover frequency to choose?
I'm searching a good sounding 12" woofer with a sensivity of 92 93 db.
An externally hosted image should be here but it was not working when we last tested it.
Thanks in advance for your help.
Sabry
Troels crosses over the HDS 134s at ~3Khz, & 2.5 is what the manufacturer recommends for the Fountek, so it should be OK;
at the low end it depends on how you're dealing with baffle step, the simplest solution is to cross the woofer over at the baffle step freq, in your case ~ 575Hz
Don't limit yourself to 12" drivers - there are plenty of 8 & 10" drivers out there with good low end performance, and you'll probably find that their lower Vas makes it easier to get an acceptable sized cabinet
at the low end it depends on how you're dealing with baffle step, the simplest solution is to cross the woofer over at the baffle step freq, in your case ~ 575Hz
Don't limit yourself to 12" drivers - there are plenty of 8 & 10" drivers out there with good low end performance, and you'll probably find that their lower Vas makes it easier to get an acceptable sized cabinet
Hi,
Use L-R 4th order @ 3000Hz and 80Hz. Due to your side firing woofer, you cannot cross it too high as the upper bass might become localized. Bear in mind that you'll need huge inductors for the bass crossover 😱
For the woofer I'd use a Fostex FW305 - 95dB SPL. The huge inductors you'll need to use will suck the life out of the woofer so the bonus sensitivity is a good thing !
IMO your design requires very high quality midwoofers which can handle the upper bass very well. If not , they will start sounding thin.
Use L-R 4th order @ 3000Hz and 80Hz. Due to your side firing woofer, you cannot cross it too high as the upper bass might become localized. Bear in mind that you'll need huge inductors for the bass crossover 😱
For the woofer I'd use a Fostex FW305 - 95dB SPL. The huge inductors you'll need to use will suck the life out of the woofer so the bonus sensitivity is a good thing !
IMO your design requires very high quality midwoofers which can handle the upper bass very well. If not , they will start sounding thin.
no low cut on midwoofers
active dsp on woofer
woofer?
CSS TRIO8 from USA, "affordable" and no problem to import 4 woofers, 2 each speaker
I do not know it, but for the money I doubt you find better
active dsp on woofer
woofer?
CSS TRIO8 from USA, "affordable" and no problem to import 4 woofers, 2 each speaker
I do not know it, but for the money I doubt you find better
I was not sure about the crossover frequency because the distance between both midwoofer is almost 10" and i'm supposed to cross it lower then 2k to avoid bad lobing (d'appolito theory) but that's my first MTM design, so i don't know how if it will be ok with a 3K HPF.
I have a volume of 80L for the woofer, i don't want use a fat 12" subwoofer, i would like to find a woofer that goes to 30hz but without comprise in sound quality.
In fact, in the PA professional field, a lot of engineers cross differently both midrange, one is cross at the same frequency as the tweeter, and the other one is cross lower depending on the distance between both mid's.
But, i would like to do it as good as i can, that's my first HIFI cabinet, so i need your help for the desing.
I can change the design from MTM to MMT.
It will be 2 way active between the woofer and the mid, passive between the mid and the tweeter. I will cross it with digital processor like the Dolby lake.
i will check the fostex, thanks for the advise
I will use a DSP processor between the 12 and mid's, passive crossover between mid's and the tweeter.
Ahh I see. You're using active on the woofers !
I wanted to suggest a good old Peerless XXLS 12'' but that probably will be classified as "fat bass". The Fostex 12'' should be quite satisfying in a 75-80L bass reflex tuned to 30Hz.
Let us know your max budget for each woofer.
I wanted to suggest a good old Peerless XXLS 12'' but that probably will be classified as "fat bass". The Fostex 12'' should be quite satisfying in a 75-80L bass reflex tuned to 30Hz.
Let us know your max budget for each woofer.
Actually, i already have all the speakers except the 12", i still have on stock two 12" from Beyma with large xmax and 94db sensivity.
I'm not pretty sure to use them because this driver was design to make real high sensivity at low frequency.
But some people told me that the sound is dirty, almost no detail.
I'm searching a 12" that can go deep, 93db sensivity and good sounding from 30hz to 80hz.
For the price range, i can go to 200€ per driver. I don't want to blow out my budget.
Consider running the two mids together and tweeter on top or under depending on ear height. It will be easier to XO.
Also consider a smaller woofer on either side of the cabinet. Don't worry about sensitivity, you're running them active.
Also consider a smaller woofer on either side of the cabinet. Don't worry about sensitivity, you're running them active.
Good idea to put one woofer on each side, i'm not sure it will fit in the box, the width is not big enough.
For the mid, you think i should do a MMT and cross differently each mid?
I have not heard of wiring the two mids differently but perhaps someone else can help. I think the two mids together is good. Spread apart you have to cross your tweeter too low.
Hi Cal and Sabry,
I've tried TMM with both mids running the same freq range and it really smears the imaging and soundstage even with fairly close woofer spacing. To avoid this, just add a baffle step compensation to the lower woofer if you go TMM. I personally use a 12dB/oct slope for my lower woofer. For your baffle width, probably aim for 400Hz crossover point. IMO aim for MTM. TMM would need another large inductor for the lower woofers = more cost and less efficiency due to the DCR of the inductor.
A great suggestion by Cal is to put 2 smaller woofers on either side of the cabinet. I'm not sure what you mean by not enough space on the baffle. Considering that the 2 smallers woofers would be about 8'' , surely theres plenty of room =)
Regards,
Dinesh
I've tried TMM with both mids running the same freq range and it really smears the imaging and soundstage even with fairly close woofer spacing. To avoid this, just add a baffle step compensation to the lower woofer if you go TMM. I personally use a 12dB/oct slope for my lower woofer. For your baffle width, probably aim for 400Hz crossover point. IMO aim for MTM. TMM would need another large inductor for the lower woofers = more cost and less efficiency due to the DCR of the inductor.
A great suggestion by Cal is to put 2 smaller woofers on either side of the cabinet. I'm not sure what you mean by not enough space on the baffle. Considering that the 2 smallers woofers would be about 8'' , surely theres plenty of room =)
Regards,
Dinesh
The depth inside the box is 8" (20cm), i need to find two 10 or 8" low profile. Or i need to place one abvove the other.
A Hi-Vi D10G or D10.8 will play nicely in ~80L sealed, F3 at 45Hz, F10 at 26Hz, lovely slow roll-off. Can play up higher than a beefy subwoofer driver too (D108 especially, flat to 400Hz) and has high power handling. Should sound great in-room 🙂
EDIT: relating to above dual-woofer discussion, a pair of Hi-Vi D8.8 drivers may work. Shallow mounting depth just 96mm each. Not sure of response on these though.
2 D8.8 in 80L vented gives -3dB at 30Hz, -10dB at 23Hz, and 2 Hi-Vi M8A give a similar result, both tuned at 30Hz, M8A is 99mm mounting depth 🙂
EDIT: relating to above dual-woofer discussion, a pair of Hi-Vi D8.8 drivers may work. Shallow mounting depth just 96mm each. Not sure of response on these though.
2 D8.8 in 80L vented gives -3dB at 30Hz, -10dB at 23Hz, and 2 Hi-Vi M8A give a similar result, both tuned at 30Hz, M8A is 99mm mounting depth 🙂
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Hi guys,
I changed a little bit the design to fit two D10.8.
As shown on the first pictures, there are three bracing, i would like to know if it's enough for this cabinet.
Thanks in advance for your help.
I changed a little bit the design to fit two D10.8.
As shown on the first pictures, there are three bracing, i would like to know if it's enough for this cabinet.
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.
Thanks in advance for your help.
Last edited:
2 of those per side should get you plenty of low end output. How much internal volume has the revised cabinet got? I assume they are sealed. You could go as low as 90L for the pair and not need any correction for the higher Q I reckon. If you have much less then I wouldn't worry, since you are driving these actively you can incorporate a Linkwitz transform circuit or digital equivalent to correct cabinet Q and also extend the low frequency response if you desire.
Using 2 woofers will reduce cabinet vibrations, which is a good thing. Try to couple the woofers together solidly. The easiest way I can think of is to mount the pair with threaded rod running from one to the other. A basket with so many mounting holes should ensure excellent coupling with this technique.
The bracing, I'm unsure. It should be enough for the woofers, but you need a lot of braces to break up cabinet resonances in the higher ranges where your mids operate. You appear to have a flat divide between the mid section and bass? It might also be nice to use an angled or otherwise non-parallel separator here 🙂
This is a really attractive design which should certainly have the potential to perform brilliantly too 😎
Using 2 woofers will reduce cabinet vibrations, which is a good thing. Try to couple the woofers together solidly. The easiest way I can think of is to mount the pair with threaded rod running from one to the other. A basket with so many mounting holes should ensure excellent coupling with this technique.
The bracing, I'm unsure. It should be enough for the woofers, but you need a lot of braces to break up cabinet resonances in the higher ranges where your mids operate. You appear to have a flat divide between the mid section and bass? It might also be nice to use an angled or otherwise non-parallel separator here 🙂
This is a really attractive design which should certainly have the potential to perform brilliantly too 😎
The internal volume is 130L, i need to remove the volume of the port if i make it vented and the volume of both 10".
I'm not sure if i will go sealed or vented. I need to make few simulations with Leap5, i'm still waiting for the LTD file from HIVI.
Great idea, i will do it for sure.
The volume for the mid is half the depth of the box, there is a bracing that can be seen on the first pics (page 1). I can add bracing to breakup resonances in this volume.
Thanks a lot for your help. I will update the design.
I will try to keep this topic up to date.
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