Hi all,
Just what you need I expect, another newbie with a question or two you've probably all heard before. I hope you will forgive me if this gets a little basic.
I am looking to build a subwoofer. The only things that are definite at this stage are the amp (I have the Redgum RGSW-1 amp - 180 watts into 8ohms) and the size of the sealed box (which if it exceeds about 54 liters my wife will be going like this:
). My room is small at 4mx4mx3.5m. I have been looking at using the Adire 54 liter sealed enclosure design with the Shiva MkIII which I will probably have front firing for reduced decay.
As it will be used for both music and home theatre, and I am very picky about my music, a relatively flat in-room response is preferred, and minimal boost in the mid-bass region. A nice 'whack' would be nice though for HT (I want everything really)
Has anyone had experience with this combination? Is it audible below 20Hz or is this an unreasonable expectation in a sealed box of this size? Would another driver/enclosure combination give me a flatter response and more extension in the bass?
Would look at designs with 2 x 12 in parallel or a 12 with a PR as long as the box size remained reasonable and the enclosure is capable of being put together by a handyman who is a complete klutz.
I seem to remember seeing a relatively small design on the web for 2 x 12 in parallel a smallish box, but haven't found it again.
Hope you can help.
Just what you need I expect, another newbie with a question or two you've probably all heard before. I hope you will forgive me if this gets a little basic.
I am looking to build a subwoofer. The only things that are definite at this stage are the amp (I have the Redgum RGSW-1 amp - 180 watts into 8ohms) and the size of the sealed box (which if it exceeds about 54 liters my wife will be going like this:
). My room is small at 4mx4mx3.5m. I have been looking at using the Adire 54 liter sealed enclosure design with the Shiva MkIII which I will probably have front firing for reduced decay.As it will be used for both music and home theatre, and I am very picky about my music, a relatively flat in-room response is preferred, and minimal boost in the mid-bass region. A nice 'whack' would be nice though for HT (I want everything really)
Has anyone had experience with this combination? Is it audible below 20Hz or is this an unreasonable expectation in a sealed box of this size? Would another driver/enclosure combination give me a flatter response and more extension in the bass?
Would look at designs with 2 x 12 in parallel or a 12 with a PR as long as the box size remained reasonable and the enclosure is capable of being put together by a handyman who is a complete klutz.
I seem to remember seeing a relatively small design on the web for 2 x 12 in parallel a smallish box, but haven't found it again.
Hope you can help.
I have been using a Shiva Mk I in a box about 48 litres (i had it around), and it works fine. With room lift it goes down to where you can only feel it. A bigger box (or same size but aperiodic) would be better for hifi and probably take you even lower.
The Shiva isn't as good at matching with my sats as my 2x8" stereo woofers, but those are in bigger boxes and don't go as low with as much impact.
We have had some good results with 2x12 push-push in 2.5+ cu ft aperiodic boxes. These use extended range 12s as opposed to subs so they go considerably higher for better merging with the sats -- you do need the 2 12s in this case to keep up with the volume displacement of a single Shiva.
dave
The Shiva isn't as good at matching with my sats as my 2x8" stereo woofers, but those are in bigger boxes and don't go as low with as much impact.
We have had some good results with 2x12 push-push in 2.5+ cu ft aperiodic boxes. These use extended range 12s as opposed to subs so they go considerably higher for better merging with the sats -- you do need the 2 12s in this case to keep up with the volume displacement of a single Shiva.
dave
Thanks Exision. Have downloaded winISD and having a bit of a play. That is a very handsome cabinet around the 10inch woofer. I am allowed to go a little bigger but not up to your 'fridge' I am afraid. It's going to have to be 54-60 litres.
Thanks also Dave. That sounds low enough, maybe the 54 litre will do fine for HT. I have a pair of large Duntechs which are flat down below 35Hz so maybe I shouldn't bother with the sub for music??
What is it about the 2 x 8" woofers you prefer over the Shiva for music? Do you recommend a bigger box because the smaller box with the higher Q has that whack in the mid bass? We tend to listen to R&B, funk and Acid Jazz is that less of a problem with this kind of music??
I am afraid I don't understand 'aperiodic'. I have seen you link in another post to a picture with two speakers in a little box with a big tube coming out of the top, is this what you are referring to?
I have seen a couple of posts from people who seem to have used the Shiva 54 litre box, Viper073 and possibly Jazzman. Be interested in hearing how it all turned out if you have the time.
Thanks for the advice.
Regards,
Allan
Thanks also Dave. That sounds low enough, maybe the 54 litre will do fine for HT. I have a pair of large Duntechs which are flat down below 35Hz so maybe I shouldn't bother with the sub for music??
What is it about the 2 x 8" woofers you prefer over the Shiva for music? Do you recommend a bigger box because the smaller box with the higher Q has that whack in the mid bass? We tend to listen to R&B, funk and Acid Jazz is that less of a problem with this kind of music??
I am afraid I don't understand 'aperiodic'. I have seen you link in another post to a picture with two speakers in a little box with a big tube coming out of the top, is this what you are referring to?
I have seen a couple of posts from people who seem to have used the Shiva 54 litre box, Viper073 and possibly Jazzman. Be interested in hearing how it all turned out if you have the time.
Thanks for the advice.
Regards,
Allan
Get hold of winisd and play with box sizes: http://www.linearteam.dk/
I think you'll find a peak with the shiva sealed @ 54Litres (esp. in room response)
At 54 litres - ported is not an option (to small for a shiva). Go sealed - more forgiving in design than trying to get a ported tuned right.
I have a RGSW2 powering mine (running at 4ohms to suck 300 watts out of it). I think the redgum amps are great - but they seem to have gone up a lot in price - you might want to check out: http://www.jaycar.com.au
There is even an Aus distributor for the hypex sub plate range: http://www.istnet.net.au/~jwgutier/page2-hypex_intro.htm - eg. the HS200 would be good.
All the best,
Dave.
I think you'll find a peak with the shiva sealed @ 54Litres (esp. in room response)
At 54 litres - ported is not an option (to small for a shiva). Go sealed - more forgiving in design than trying to get a ported tuned right.
I have a RGSW2 powering mine (running at 4ohms to suck 300 watts out of it). I think the redgum amps are great - but they seem to have gone up a lot in price - you might want to check out: http://www.jaycar.com.au
There is even an Aus distributor for the hypex sub plate range: http://www.istnet.net.au/~jwgutier/page2-hypex_intro.htm - eg. the HS200 would be good.
All the best,
Dave.
bigkid said:
The 2 8s go a lot higher than the Shiva (3k vrs 150 Hz) so it is much easier to get them to blend with the mains.
You want to put the Shiva in as large a box as you can get away with -- so if you can do 60 litres go for it.
No, that picture is a push-push TL. Aperiodic is best visualized as a sealed box with a controled leak or a BR with a stuffed port. It is more closely related to a TL thou. I use this when i can't live with a sealed box that is big enuff. My recipe is to build as big a box as possible, then to put some holes in the box and "stuff" them. Lots of little drill holes or some longish narrow slots. I use a combination of foam & compressed fiberglass insulation. What it does is to reduce the peak in the too small sealed box and flatten the impedance curve. The Dynaco A25 7 A10, the SynaAudio VarioVent, and the PEARL PR-2 are all commercial examples.
dave
Thanks for the details Dave Bullet and Dave Moderator.
I have discovered the Linkwitz site. Most of it is beyond me but he does seem to get a good flat bass response from the Thor, ideal for music.
As I understand it he uses a small enclosure and compensates for the quick roll-off in the bottom end of the bass by using a simple EQ circuit to boost those signals. The EQ sits between the processor/pre output and the input of the poweramp which powers the sub. Have I got it right?
One thing I don't understand. With the sketch of the Thor and the EQ circuit diagram on the web page, why would anyone pay US$160 for the plans, or is this just to stop people from bugging Mr Linkwitz for plans etc?? I am right aren't I, there does seem to be enough information on his web page to build sub with a response like the Thor? Or have I missed something?
I have discovered the Linkwitz site. Most of it is beyond me but he does seem to get a good flat bass response from the Thor, ideal for music.
As I understand it he uses a small enclosure and compensates for the quick roll-off in the bottom end of the bass by using a simple EQ circuit to boost those signals. The EQ sits between the processor/pre output and the input of the poweramp which powers the sub. Have I got it right?
One thing I don't understand. With the sketch of the Thor and the EQ circuit diagram on the web page, why would anyone pay US$160 for the plans, or is this just to stop people from bugging Mr Linkwitz for plans etc?? I am right aren't I, there does seem to be enough information on his web page to build sub with a response like the Thor? Or have I missed something?
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