Sealed subwoofer project

[Farmer]

Hi,

I'm thinking about building a subwoofer as a school project(but first I have to get out of the Finnish army, 7 months of coastal jaeger left) It's mainly for music so I think a sealed box is what I want. The problem is I have absolutely no idea of what driver or amp to get, I've read that the peerless xls 12" is supposed to be a good choice but as far as amps I have no idea, another problem is that I live in Finland and I don't really know what's available over here, any fins around to help?

[Lobotomy^]

You still have 7 months of time to get to know whats going on in woofer world. At the moment most recommended woofer sizes seems to start from 15", which also should be enough for any normal Finnish home.
XLS12 is quite good woofer, but its recommended to port or passive tuned enclosures. Here is my version of it. These sub measurements also are one to watch when you try to find what to build. Those have proven couple starting trends in woofer worlds to be valid.

Also you should consider asking same question in Finnish forum @ www.dvd-plaza.fi . You'll get little more local information where to by woofers and amps. That forum is also the another home of Zipman, guy who made those woofer measurements linked above.

[imbeaujp]

Hello,

Here are some design with the peerless XXLS series :

http://www.solen.ca/v1/sxxls.htm


Pick the one you like !

[Farmer]

Hmm Interesting... how necessary is the port really? I've read that sealed subs have a lot better transient response, and it will be a music sub so I don't really need it to play flat down to 20hz and below, I will be watching movies too with it but the music comes first. My speakers are a pair of Wharfedale diamond 9.1's and my stereo amp is an old Harman/kardon 430 twin powered, I might get a new one tho when I get out of the military, I'm looking at getting the Cambridge audio azur340A SE

at http://www.hifitalo.fi/ I can get an xxls12" aluminum(or is the regular xls12" just as good?) at 200€ and the hypex DS2.0 is at 300€ so that makes 500€ and I don't really want to spend any more cause you don't exactly get rich In the Finnish military...

Lobotomy, I noticed you got the DS4.0 in yours, do you think the DS20 will do?

Also what's the difference(if any) on down firing and front firing?

[Lobotomy^]

Hypex DS 2.0 is usually enough for XLS12. Although more powerful amp will give more control, that is why little more headroom is usually recommended. During measurements DS 4.0 was not enough for XLS12 in every measurements. Loud clipping of the amp was seen.

In case of Hifitalo, I recommend asking invoise from them, by askin you usually get 10-20% off from price, depends how big your order would be.

XXLS 12 aluminium has little more excursion and therefore might be able to give you little more spl, if amp has enough power. It also requires little more bigger encloseure than XLS12. For enclosure recommendations, go to the dvd-plaza. Some guy is making sub from XXLS12 there.

Facing of woofer doesn't matter. At low frequencys sound spreads 360 degrees and around corners. Downfiring subs however starts floor-roof roommodes more easily as the woofer is closer to floor. For example Harri from Harrin kaiutin desings his subs to be top part of enclosure as far from floor as possible for this reason. Although hirgher it is, more unstable enclosure comes when woofers shakes it, atleast with subs that have small footprint.

Closed subs are usually considered better on transient response, but they easily lack power in bigger rooms. Search for information about LLT from this forum, it is said to have best sides of sealed and and bass reflex enclosures. I haven't heard one myself, although that my sub is a bit similar.

[norcad]

Hello
I have tested the XLS12 in sealed, BR an d with two passive radiators. I agree that you should go for the DS 4,0. And for music listening you should go for 45-50L closed box.
With the built-in EQ in DS 4,0, you can get close to flat respons down to 20-25hz if you want to in most rooms.

In the attachment you see my measurments of the XLS12 i a 45L closed box, the first is without eq, and the second is with max eq (+6dB)

[haraldo]

norcad wrote:

Hello
I have tested the XLS12 in sealed, BR an d with two passive radiators. I agree that you should go for the DS 4,0. And for music listening you should go for 45-50L closed box.
With the built-in EQ in DS 4,0, you can get close to flat respons down to 20-25hz if you want to in most rooms.

In the attachment you see my measurments of the XLS12 i a 45L closed box, the first is without eq, and the second is with max eq (+6dB)

Are those measurements where sub is corner placed, or placed where it's supposed to be located?

Depending on where you locate the sub's, a quite considerable amount of room gain is involved, which means you'll get a lot of help with the SPL levels at the lowest frequencies, you may not necessarily need all that EQ.....

regards

Harald N

[norcad]

To be honest, I'm not 100% sure. This was one of my first measurements, made a couple of years ago. I do remember that the sub was placed in the middle of the room, and not in a corner. And I believe this is a nearfield measurement.
I usually dont use full eq, it was just measurements to see how it would work.
In this closed box, and with full eq it is possible to reach xmech with this driver. But in my music collection I have found only one record where this happens.

[haraldo]

norcad wrote:

To be honest, I'm not 100% sure. This was one of my first measurements, made a couple of years ago. I do remember that the sub was placed in the middle of the room, and not in a corner. And I believe this is a nearfield measurement.
I usually dont use full eq, it was just measurements to see how it would work.
In this closed box, and with full eq it is possible to reach xmech with this driver. But in my music collection I have found only one record where this happens.

Later... I can show you some graphs that really visually illustrate how much "help" you get from the room when it comes to low end extension with a subwoofer...This may also explain why some sub's are too "boomy"

Generally you may get as much as 9dB increase in SPL at 20 Hz if you put the sub in a corner. If the subwoofer is linear to 20Hz and you put it in a corner you will get close to 10dB increase is level, which is why sub's should be designed for the room and not to be linear in an anechoic chamber

[norcad]

+10 dB @ 20Hz is just fun!
I know what room gain can do. But there isnt two rooms and woofer placements in the world that is exactly the same. So measurements should not be done with room gain. The problem is that very few people know what will happen in their own room, in their own corners!

[haraldo]

norcad wrote:

+10 dB @ 20Hz is just fun!
I know what room gain can do. But there isnt two rooms and woofer placements in the world that is exactly the same. So measurements should not be done with room gain. The problem is that very few people know what will happen in their own room, in their own corners!

Couldn't agree more, but it's still quite predictable if you happen to put the sub in a corner..... :-)

[Farmer]

Cool, my thread is still alive, haven't checked it lately cause I've been living in the woods the last 2 weeks.

Hmm, are there any other good amps that I can easily get overe here without having to order outside europe, preferably below 300€. I'd also like it to have both highlevel in and then out again so my speakers wouldnt need to reproduce frequencies below 60hz as this puts alot of stress on them and affects the sound...