Hello Friend,
I already designed 5.1 amplifier, satellite spk & sub woofer.
6" 8ohm woofer spk.
You can see in http://gigaamp.com
But i didn't satisfy that.
Woofer amp power is small.
So, I designed bridge/parallel amp with tda2030.( from national )
( Old one is designed in bridge. )
And then I put another 6" 8ohm woofer spk.
Two spk join in out of phase in parallel.
I screwed two spk front to front.
But woofer sound is no good at all.( more disappoint ).
I reduce or increase the pipe of the port ( try-and-error ).
One spk is better than two spk.
Pls, help me for subwoofer design.
sorry for my poor english.
How can I calculate my design?
How can I design my subwoofer?
I already designed 5.1 amplifier, satellite spk & sub woofer.
6" 8ohm woofer spk.
You can see in http://gigaamp.com
But i didn't satisfy that.
Woofer amp power is small.
So, I designed bridge/parallel amp with tda2030.( from national )
( Old one is designed in bridge. )
And then I put another 6" 8ohm woofer spk.
Two spk join in out of phase in parallel.
I screwed two spk front to front.
But woofer sound is no good at all.( more disappoint ).
I reduce or increase the pipe of the port ( try-and-error ).
One spk is better than two spk.
Pls, help me for subwoofer design.
sorry for my poor english.
How can I calculate my design?
How can I design my subwoofer?
what you did is called an isobarik configuration. When you mount to woofers together like this (front to front) the Vas is reduced by one half, and the box needs to be half the size and the port needs to be more than twice the length, or maybe a smaller port.
If you have the T/S parameters of the woofers then I could give you an idea of what port to use, the box needs to be half size though.
Using the same port or shorter will raise the tuning resulting in a huge resonant peak, making it sound like the sub only produces one bass note instead of the whole bass spectrum.
Hope this helps a little
BTW winisd is free to download and will help you in designing woofer enclosures.
If you have the T/S parameters of the woofers then I could give you an idea of what port to use, the box needs to be half size though.
Using the same port or shorter will raise the tuning resulting in a huge resonant peak, making it sound like the sub only produces one bass note instead of the whole bass spectrum.
Hope this helps a little
BTW winisd is free to download and will help you in designing woofer enclosures.
Hello Friend,
Thanks for the softare.
I will try & test with that software.
How can I get Fs,Qes,Qms,.......?
In our country cannot get that data.
Ohm & watts are not the same which is type on the spk.( made in china or thailand ).
So, How can I calculate & test to get that data of my spk?
Can you give me general calculation for speaker?
Pls, continue help me.
Thanks for the softare.
I will try & test with that software.
How can I get Fs,Qes,Qms,.......?
In our country cannot get that data.
Ohm & watts are not the same which is type on the spk.( made in china or thailand ).
So, How can I calculate & test to get that data of my spk?
Can you give me general calculation for speaker?
Pls, continue help me.
Ok, now it gets difficult. If you can download Speaker Workshop from the website, and from searching the diyaudio forums you can get a link to the "unofficial speaker workshop manual 2.0" it will help you through the program. you will also need the wallin jig or equivalent, the manual will help you with that, or search here for more info.
I have to warn you the program is hard to learn, especially if you have trouble understanding english. You have two other options:
1. bring the speakers to someone in you area and have them test them.
2. Just buy two woofers (or one good one) from a website like partsexpress or wherever, that includes the necesary parameters, Fs,Qes,Qts,Qms,Vas.
Good luck
Actually, there is a number three option:
3. I randomly selected 5 woofers from the winisd databse, and modeled them as single woofer and isobarik, each time the box size was reduced by one half and the port lenth was increased by a factor of (average) 2.10, the lowest factor was 2.05 and the largest was 2.126, so I would recommend buying an adjustable length port and initially setting it to 2.1 times the length of the one you have and tuning by ear or with a spl meter and a sine sweep function, I think you should be able to get a close enough tune that way.
You can also try this experiment with winisd if you want.
Hi nunayafb,
You said box size reduce 1/2 & pipe length increase 2.1 times.
Box size reduce when pipe length increase. ( in my woofer ).
Is that right?
Need to calculate pipe volume in the woofer?
Box size will not reduce 1/2 if pipe volume need to calculate.
Box size will reduce under 1/2.
In my subwoofer,
Can I need to calculate bottom of the box volume (between spk & ground)?
Pls, reply me.
Thanks.
You said box size reduce 1/2 & pipe length increase 2.1 times.
Box size reduce when pipe length increase. ( in my woofer ).
Is that right?
Need to calculate pipe volume in the woofer?
Box size will not reduce 1/2 if pipe volume need to calculate.
Box size will reduce under 1/2.
In my subwoofer,
Can I need to calculate bottom of the box volume (between spk & ground)?
Pls, reply me.
Thanks.
Attachments
I am pretty sure you do not need to worry about the volume of the port, I have never heard anyone mention that before. No time right now but tonight I'll check my book and make sure.
I just noticed in the photo that the woofer fires down, are you going to have enough room for isobarik, or are you going to raise the box up?
I just noticed in the photo that the woofer fires down, are you going to have enough room for isobarik, or are you going to raise the box up?
Not sure, youll have to try it, winisd does not let you change port lengths independently.
Yes, but... the losses due to bent pipes are alot less than the problems associated with the port end being to close to the wall of the enclosure. You are entering a trial and error phase. You are going to have to try several ports that are about 1.5x to 1.8x the original, to avoid proximity to the wall and sitll increase the length enough for flat enough frequency response you are not going to get a perfect response when using the wrong box size and the wrong port length. Try a longer port only see if you like the sound.
remember, you wont gain dB's with isobarik only reduce distortion.(except for the 4ohm load now instead of 8ohm which will double power consumption giving you +3dB),
The main benefit of isob. is a smaller box... you might want to cut another hole in the box for the second woofer, on the back or side to corner or wall load it. Modeling in winisd show the f3 being increased by the addition of a second woofer with no port or box alterations(other than the permanent hole in the box). two woofers in parrallel should give you about 6dB boost as well. 3 from doubling cone area and 3 from doubling power.
good luck!
Hello friend,
I disappointed to design isobarik.
Because hard to design in my box.
In my box include power supply for my amps.
So cannot long & bent enough for pipe.
Now, I design new with cylinder plastic box ( pure drinking water box in my country ).
Design passive radiator configuration.
one side attached with 6" spk & other side attached with 8" cone.
(not include spk frame & spider).
Now, my subwoofer not bad for listen.
But it can get little rumbling sound.
New passive radiator cannot compare my (6" half transmission & half seal design.)
passive radiator can get low freq when increase mass of passive radiator.
Is that true?
reduce so many bass of song & a very little increase rumbling sound when I increase mass of cone.
How can i tune that box for not many reduce bass of song & increase so many rumbling sound?
Pls, Help Me.
I disappointed to design isobarik.
Because hard to design in my box.
In my box include power supply for my amps.
So cannot long & bent enough for pipe.
Now, I design new with cylinder plastic box ( pure drinking water box in my country ).
Design passive radiator configuration.
one side attached with 6" spk & other side attached with 8" cone.
(not include spk frame & spider).
Now, my subwoofer not bad for listen.
But it can get little rumbling sound.
New passive radiator cannot compare my (6" half transmission & half seal design.)
passive radiator can get low freq when increase mass of passive radiator.
Is that true?
reduce so many bass of song & a very little increase rumbling sound when I increase mass of cone.
How can i tune that box for not many reduce bass of song & increase so many rumbling sound?
Pls, Help Me.
Well, usually you need to use T/S parameters to design an enclosure with a passive radiator. Doing it by trial and error is not easy.
Yes if you add more weight to the passive, it will tune the box lower.
The problem is you must not overweight the passive cone or the cone surround will destroy itself.
Yes if you add more weight to the passive, it will tune the box lower.
The problem is you must not overweight the passive cone or the cone surround will destroy itself.
Hello Friend,
In my photo
upper is 6"driver & lower is 8"passive radiator.
I want to put 5.1 channel amp int my that box.
So, reduce the volume of that box.
Will Frequency of my woofer be increase or decrease when I put amplifiers & powersupply in that box?
Pls,help me.
Is that more good for rumbling freq & reduce destroy itself, if i used 10"cone?
In my photo
upper is 6"driver & lower is 8"passive radiator.
I want to put 5.1 channel amp int my that box.
So, reduce the volume of that box.
Will Frequency of my woofer be increase or decrease when I put amplifiers & powersupply in that box?
Pls,help me.
Attachments
Hello friend,
I already tested with 10"passive radiator.
No good.
Sound is liked two speaker phase out.
I already tested with mass & without mass.
No good too.
How can I tune it?
For 8"passive radiator
Sound is good.
But resonace in some frequency.(some bass is more than normal
& over)
How can I tune it?
Pls help me.
Thanks.
I already tested with 10"passive radiator.
No good.
Sound is liked two speaker phase out.
I already tested with mass & without mass.
No good too.
How can I tune it?
For 8"passive radiator
Sound is good.
But resonace in some frequency.(some bass is more than normal
& over)
How can I tune it?
Pls help me.
Thanks.
Hello Friends,
Now I want to test new woofer.
Can it be use like subwoofer ?
That is
http://www.linkwitzlab.com/woofer.htm
http://www.linkwitzlab.com/woofer2.htm
http://www.linkwitzlab.com/woofer3.htm
Which design is more convient with any SPEAKERS ?
Can I replace with 10" SPKs ?
If I used other SPKs, can that be badly effect on sound quality ?
I already tested POWER AMP which is in solid amplifier FORUM ( bridge with IRF 540 & 9540 ).
http://www.diyaudio.com/forums/showthread.php?s=&threadid=80972&pagenumber=5
I want to join with that AMP.
Pls, advice me.
Now I want to test new woofer.
Can it be use like subwoofer ?
That is
http://www.linkwitzlab.com/woofer.htm
http://www.linkwitzlab.com/woofer2.htm
http://www.linkwitzlab.com/woofer3.htm
Which design is more convient with any SPEAKERS ?
Can I replace with 10" SPKs ?
If I used other SPKs, can that be badly effect on sound quality ?
I already tested POWER AMP which is in solid amplifier FORUM ( bridge with IRF 540 & 9540 ).
http://www.diyaudio.com/forums/showthread.php?s=&threadid=80972&pagenumber=5
I want to join with that AMP.
Pls, advice me.
If It Was ME
I'd buy this.
http://www.woofertester.com/
Find My Subs Parameters
Go here and determine optimum vented parameters.
http://www.linearteam.dk/default.aspx?pageid=newdriver
Calculate my PR mass using this equation.
Mpr=(151060*(R)^4)/(4*Vb*Fb^2)
R is the effective diameter of the PR. typically 10 inches for a 12 inch PR. It is measured in meter in the equation above.
Vb is the box volume in (m^3)
Fb is the box tuning frequency in (Hz)
Mpr would be the cone mass in kilograms for the PR.
If you need vent parameters calculate it here.
http://www.carstereo.com/help/Articles.cfm?id=31
I'd buy this.
http://www.woofertester.com/
Find My Subs Parameters
Go here and determine optimum vented parameters.
http://www.linearteam.dk/default.aspx?pageid=newdriver
Calculate my PR mass using this equation.
Mpr=(151060*(R)^4)/(4*Vb*Fb^2)
R is the effective diameter of the PR. typically 10 inches for a 12 inch PR. It is measured in meter in the equation above.
Vb is the box volume in (m^3)
Fb is the box tuning frequency in (Hz)
Mpr would be the cone mass in kilograms for the PR.
If you need vent parameters calculate it here.
http://www.carstereo.com/help/Articles.cfm?id=31
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.