Subwoofer module

[muad]

Hi all,

I want to build 2 subwoofer stands for my LS50 metas. Looking to cross them over with the minidsp and want them to crossover between 100 and 200hz. I was looking at modifying a css subwoofer kit like: https://www.css-audio.com/online-store/3-Way-Bass-Module-Add-On-Pair-p350688026

I'm just wondering if anyone had any input on this. I was planning on making the cabinet narrower and taller. I was hoping to mount the PR and driver on the back to keep them away from kids fingers etc. Does it matter if the PR and driver differ in placement?

 

[alex-z]

That kit is a bit expensive for the performance, particularly due to the included passive crossover components. I would recommend doing a sealed design for ease of construction and just using the miniDSP to apply a Linkwitz Transform, which extends your bass response at the cost of output headroom.

Something like an Ultimax 12" per tower running off a Crown XLS1502.

Home

Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per CoilDayton Audio UM10-22 10" Ultimax DVC SubwooferExperience the Apex of Subwoofer DesignThe Ultimax Series of dual voice coil subwoofers, from Dayton Audio, are not for the faint of heart. Built using the latest in subwoofer technology...

www.parts-express.com

If you do use a passive radiator, it can be placed anywhere on the box. Although much like a ported speaker, if there are any resonances, front firing is less desirable because they are aimed directly towards the listener.

 

[DanielT]

Here are tips on different sub drivers with low distortion. You can do EQa afterwards, so choose a driver with low distortion. You can not do anything about the distortion of the driver itself afterwards, so it's just as good to take a good one from the beginning.

Subdrivers. Then it is the ability to pump air that counts. Surface on driver and decent x-max (at least 10 mm). After that a mathematical exercise.

Brache up the box really good. Then the resonance frequencies will push up in frequency and get rid of that debris. Of course sensible HP-LP filter then.

I did not compile that compilation. Data taken from:

HiFiCompass |

hificompass.com

There are some other interesting graphs in that thread:

faktiskt.io • Visa tråd - 4: Suboptimeringar?

Regarding stuff a sub with moff plus picture of a really braced sub here:

Filling/stuffing in Subwoofer?

Hi I am grateful if anyone could sort this out; Is there any point in having filling in a Subwoofer? The question based on the assumption of an otherwise well-constructed Subwoffer, with , for example,cross braces in the box and with steep LP filter, for example 24 dB, crossover frequency 80 Hz...

audiosciencereview.com

Classic DIY trick to reduce second ton distortion for sub. See picture assembly of elements. They should sit close together. DIY under the sofa sub (not mine).

faktiskt.io • Visa tråd - Soffsub

There were some tips from my side. Note I am basically a beginner myself. It was just a little I picked up right now. In detail, I can not give more answers. More experienced people can help you with that.

Good luck with your DIY sub !!

 

[Yevhen]

Sofa sub!!!

 

[Yevhen]

I just finished a 30L sealend box project on http://www.loudspeakerdatabase.com/SB/SB34SWPL76#4Ω . Very punchy even with a cheap class D amplifier from Aliexpress. 12" rules.

 

[Yevhen]

I would think twice about the DSP as it takes like 50-60% of the budget. I think it's only necessary when the position of sub is fixed and you can't move it to the sweet spot

 

[DanielT]

I just finished a 30L sealend box project on http://www.loudspeakerdatabase.com/SB/SB34SWPL76#4Ω . Very punchy even with a cheap class D amplifier from Aliexpress. 12" rules.

Nice.. Seems good.

This one I slammed together yesterday. A test. They sold casting tubes made of
cardboard cheaply in one place. The driver is an old Philips 8" that I got for free. Looks a bit so and so in the pictures. Has glued 8" directly to the tube. Fascinating with acoustics. As you can see in the picture, I fire the cannon directly into a corner. Hell what it gave bass support, support. He he.

34 liters sealed.

Edit:
Is such a pipe enough? Well. I think it turned out surprisingly well. Should you build something more, or better sub (nice expensive driver) and use such a pipe, check with more experienced people who know this with acoustics, materials and so on. As a fun easy cheap try on DIY, however, I can really recommend it.Glue, pipe, drive 8 "(free) some planks I got on the hardware store. Total cost: $13
(I was a little lucky when I got everything so cheap)

My motto when it comes to DIY. The most important thing is to have fun ..

 

[Yevhen]

Nice.. Seems good.

This one I slammed together yesterday. A test. They sold casting tubes made of
cardboard cheaply in one place. The driver is an old Philips 8" that I got for free. Looks a bit so and so in the pictures. Has glued 8" directly to the tube. Fascinating with acoustics. As you can see in the picture, I fire the cannon directly into a corner. Hell what it gave bass support, support. He he.

34 liters sealed.

Edit:
Is such a pipe enough? Well. I think it turned out surprisingly well. Should you build something more, or better sub (nice expensive driver) and use such a pipe, check with more experienced people who know this with acoustics, materials and so on. As a fun easy cheap try on DIY, however, I can really recommend it.Glue, pipe, drive 8 "(free) some planks I got on the hardware store. Total cost: $13
(I was a little lucky when I got everything so cheap)

My motto when it comes to DIY. The most important thing is to have fun ..

Nice! Is your pipe open or closed in the end? You could try to make a hole there, it will act as the port or even transmission line

 

[muad]

That kit is a bit expensive for the performance, particularly due to the included passive crossover components. I would recommend doing a sealed design for ease of construction and just using the miniDSP to apply a Linkwitz Transform, which extends your bass response at the cost of output headroom.

Something like an Ultimax 12" per tower running off a Crown XLS1502.

Home

Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per CoilDayton Audio UM10-22 10" Ultimax DVC SubwooferExperience the Apex of Subwoofer DesignThe Ultimax Series of dual voice coil subwoofers, from Dayton Audio, are not for the faint of heart. Built using the latest in subwoofer technology...

www.parts-express.com

If you do use a passive radiator, it can be placed anywhere on the box. Although much like a ported speaker, if there are any resonances, front firing is less desirable because they are aimed directly towards the listener.

Yeah it is a bit expensive. There's also the Jeff bagby 3 way kits, that convert the continuum or Kairos into a 3 way, and they're closer to $500 a pair. But you're right, in any case I would be paying for a crossover I don't need. Alternatively I could just hook up the sub using the passive crossover. Jeff wrote in his white paper that it crosses over at 200hz with a 1st order high pass for the mains.

I was originally looking at the ultimax but I have been reading about reliability issues, which scared me away.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://meniscus.lightningbasehosted.com/wp-content/uploads/2018/03/The-Kairos-and-Continuum-Three-Way-Writeup.pdf&ved=2ahUKEwiQjZrgyLr0AhVyCTQIHdXaCxMQFnoECBAQAQ&usg=AOvVaw3MI9KeqKxvkobN_agZMJJ_

 

[muad]

I just finished a 30L sealend box project on http://www.loudspeakerdatabase.com/SB/SB34SWPL76#4Ω . Very punchy even with a cheap class D amplifier from Aliexpress. 12" rules.

I was looking at using the 10" version to keep it narrower along with the accompanying PR. Kinda like the Kairos 3 way module from Jeff bagby.

 

[muad]

Here are tips on different sub drivers with low distortion. You can do EQa afterwards, so choose a driver with low distortion. You can not do anything about the distortion of the driver itself afterwards, so it's just as good to take a good one from the beginning.

Subdrivers. Then it is the ability to pump air that counts. Surface on driver and decent x-max (at least 10 mm). After that a mathematical exercise.

Brache up the box really good. Then the resonance frequencies will push up in frequency and get rid of that debris. Of course sensible HP-LP filter then.

I did not compile that compilation. Data taken from:

HiFiCompass |

hificompass.com

View attachment 168299

There are some other interesting graphs in that thread:

faktiskt.io • Visa tråd - 4: Suboptimeringar?

Regarding stuff a sub with moff plus picture of a really braced sub here:

Filling/stuffing in Subwoofer?

Hi I am grateful if anyone could sort this out; Is there any point in having filling in a Subwoofer? The question based on the assumption of an otherwise well-constructed Subwoffer, with , for example,cross braces in the box and with steep LP filter, for example 24 dB, crossover frequency 80 Hz...

audiosciencereview.com

Classic DIY trick to reduce second ton distortion for sub. See picture assembly of elements. They should sit close together. DIY under the sofa sub (not mine).

faktiskt.io • Visa tråd - Soffsub

There were some tips from my side. Note I am basically a beginner myself. It was just a little I picked up right now. In detail, I can not give more answers. More experienced people can help you with that.

Good luck with your DIY sub !!

Holy, the wo24p really loses it below 30hz if I'm reading that correctly.

 

[DanielT]

Holy, the wo24p really loses it below 30hz if I'm reading that correctly.

It is possible. I'm a beginner so on purely technical issues I only know the basics .It's not me who made that compilation. You can test the results of the calculations yourself. I think it is this program, which is free and free that has been used:

Tolvan Data

If you want help with any translation of the text from any of the linked threads, send me a PM and I will help you.

 

[Tangband]

Hi all,

I want to build 2 subwoofer stands for my LS50 metas. Looking to cross them over with the minidsp and want them to crossover between 100 and 200hz. I was looking at modifying a css subwoofer kit like: https://www.css-audio.com/online-store/3-Way-Bass-Module-Add-On-Pair-p350688026

I'm just wondering if anyone had any input on this. I was planning on making the cabinet narrower and taller. I was hoping to mount the PR and driver on the back to keep them away from kids fingers etc. Does it matter if the PR and driver differ in placement?

Making subwooferstands to ls50 meta is probably a very good idea.
I would make them about 60-65 cm high and I would use a SB 23 mfc subwoofer driver, put on the upper front and a bass-tube on the lower back, tuned to about 28 Hz . The volume in each subwoofer box should be about 20-25 liters.

I would not use a dsp filter , but a passive one this time.
The reason is that you dont need a dsp filter in this construction. The small distance between each subwoofer driver and LS 50 meta is good in the way that you can use a simple passive 6 dB/oct crossover, thus making it a three way.

I would try two options:

1. Crossover as a start should be at 125 Hz ( One air-coil in series at + for each sub and one capacitor in series with each ls50 at +. Same polarity sub and ls50.)
If you cross at 125 Hz you could put the SB23mfc in the bottom of the cabinet, near the floor.

Or:

2. I would also try to cross in the same way, but at the baffle step frequency for ls50 meta. Thus about 500 Hz . Genelec coaxial style . Then a smaller coil and capacitor can be used. The SB23mfc must then be placed at the top front of the subwooferstand, near the ls50 metas coaxial driver. Bass tube placed on the lower back.

And then I would use the crossover that sounds the best.

 

[DanielT]

A classic question:
One or two good subwoffer drivers vs for example four ok drivers. Same price for sub drivers.

Pros and Cons.

I think that's the first thing to think about. Weigh in size and design
the listening room they are to be placed in. Partly the acoustics in the room partly the aesthetic (possibly WAF for example).

By the way, it does not have to be WAF. For my part, I think that black ugly cubes in listening rooms, living rooms are not aesthetically pleasing. But it is a matter of taste.

 

[Tangband]

A classic question:
One or two good subwoffer drivers vs for example four ok drivers. Same price for sub drivers.

Pros and Cons.

I think that's the first thing to think about. Weigh in the listening room they are to be placed in. Partly the acoustics in the room partly the aesthetic (possibly WAF for example).

By the way, it does not have to be WAF. For my part, I think that black ugly cubes in listening rooms, living rooms are not aesthetically pleasing. But it is a matter of taste.

Making the ls50 meta a threeway takes away the modulation troubles in the ls50 driver because it dont have to deal with deep bass anymore. = less IMD distortion, better sound. Exactly the way Kef already do it in R3 and R5.

But I agree that ls50 meta looks very good on thin loudspeakerstands.

 

[DanielT]

Of course also the type of music, film you listen to plays a role in choosing type of sub. It makes a difference if you listen to hard pumping electro with a lot of bass vs bass weak singing songwriting music.

 

[muad]

So I don't think I want to do a ground up plan for the woofer module... I was thinking of using Jeff Bagby's design or the CSS woofer module design and skip the passive crossover section. I was reading Jeff's white paper and he said he found his CSS woofer module didn't work well for the kairos, but great for the continuum. He felt his woofer module with the sb29nrx worked better with the Kairos. Either way, I'm leaning heavily toward a passive radiator built. I don't want sealed and I want to avoid port noise.

Jeff also made a comment about his crossover affecting the impedance of the Kairos... I really don't know how it will affect the LS50 meta... I'm worried it will drop it's impedance too much.

1. Is there any reason to use the passive crossover or can I simply use a minidsp 2x4hd and 2 stereo amplifiers to cross the LS50 meta with the module?

2. Would the CSS sdx10 or SB29NRX be a better choice for a woofer module?

 

[DanielT]

So I don't think I want to do a ground up plan for the woofer module... I was thinking of using Jeff Bagby's design or the CSS woofer module design and skip the passive crossover section. I was reading Jeff's white paper and he said he found his CSS woofer module didn't work well for the kairos, but great for the continuum. He felt his woofer module with the sb29nrx worked better with the Kairos. Either way, I'm leaning heavily toward a passive radiator built. I don't want sealed and I want to avoid port noise.

Jeff also made a comment about his crossover affecting the impedance of the Kairos... I really don't know how it will affect the LS50 meta... I'm worried it will drop it's impedance too much.

1. Is there any reason to use the passive crossover or can I simply use a minidsp 2x4hd and 2 stereo amplifiers to cross the LS50 meta with the module?

2. Would the CSS sdx10 or SB29NRX be a better choice for a woofer module?

If I am going to DIY a subwoffer, I would, due to not enough knowledge and experience, have chosen the simplest type of construction, ie sealed. But I can understand if you want to test on another design principle. However, I can not advise you on such.

Selection of subwoffer driver. You can play with the parameters, price, x-max, spl, appropriate to the type of design principle, level distortion, how linear the frequency curve for the driver looks, impedance curve.

Subwoofer is mostly about linear air pumping capacity.

Test them here:

https://www.tolvan.com/index.php?page=/basta/basta.php

 

[muad]

If I am going to DIY a subwoffer, I would, due to not enough knowledge and experience, have chosen the simplest type of construction, ie sealed. But I can understand if you want to test on another design principle. However, I can not advise you on such.

Selection of subwoffer driver. You can play with the parameters, price, x-max, spl, appropriate to the type of design principle, level distortion, how linear the frequency curve for the driver looks, impedance curve.

Subwoofer is mostly about linear air pumping capacity.

Test them here:

https://www.tolvan.com/index.php?page=/basta/basta.php

Great thanks! I'll plug in some specs and see what happens

Thanks

 

[Duke]

Hi all,

I want to build 2 subwoofer stands for my LS50 metas. Looking to cross them over with the minidsp and want them to crossover between 100 and 200hz. I was looking at modifying a css subwoofer kit like: https://www.css-audio.com/online-store/3-Way-Bass-Module-Add-On-Pair-p350688026

I'm just wondering if anyone had any input on this. I was planning on making the cabinet narrower and taller. I was hoping to mount the PR and driver on the back to keep them away from kids fingers etc. Does it matter if the PR and driver differ in placement?

One thing you might want to be aware of is this: The mass of the passive radiator making long excursions can cause the whole cabinet to vibrate or rock, with the vibration (or rocking motion) being in the direction of the passive radiator's movement. So if you are placing the woofer and passive radiator both on the rear of the cabinet, I'd suggest placing the passive radiator below the woofer so that the force it imparts to the cabinet has a shorter lever arm. And I strongly suggest spikes underneath the sub if you're using it as a speaker stand.

You might consider placing the passive radiator on the bottom of the cabinet, and using tall spikes for the feet. This will direct the cabinet motion from the passive radiator into the vertical plane. I manufacture a speaker stand with a built-in ported subwoofer (no passive radiator) and the woofer is down-firing to reduce cabinet motion relative to having the woofer's motion in the horizontal plane.