jag said:
I think Adire -- in the Shiva white paper -- lays out the parameters of the driver wired in various configurations, so you can just pick a config and plug it in.
audioXpress also had a couple recent articles on the subject.
dave
planet10 said:
The shiva white paper does show T/S parameters for series/parallel connections. The only parameter that changes is the impedance, everything else remains same - which does make sense, but good to confirm that. The Qms is different for 'one shorted coil' config since the coil is now a brake. I am sorry, I do not want to take this thread in tangent to the original topic and will not make any more posts on this (DVC) topic.
Attachments
A Poor Result
I’ve just finished putting together my Shiva subwoofer and I must say I am a little disappointed.
I must be doing something wrong because I have read so many great reviews on this driver.
So let me re-cap my design:
I have built a 60 liter box as per the shiva design ( I increased the dimensions of the original 54 liter box using a CAD program but the design is still the same.)
I used 25mm MDF for the outside and 16mm MDF for the bracing inside.
I used silicon on every joint after the box was assembled.
I mounted the amplifier externally to the main box and used silicon again to seal the wires from the amplifier to the driver.
The amplifier I am using is a JayCar 150Watt @ 4ohm rating.
I used quite a lot of filling inside the box. I used Dacron (sheets for the internal walls and loose as filling) and basically filled it right up to the clearance point for the driver. This includes the holes cut out in the bracing.
I connected the driver in parallel (refer attached)
Finally, I attached a foam seal to the perimeter of the driver before I screwed it in.
The Result?
Well basically, I hooked it up to my Sony amplifier (5x100 watts) and played a DVD. I adjusted all the settings on my amp and the subwoofer was working. However, the sound sounded boomy and it didn’t seem to have much grunt. There was no punchyness to the sound. I put a music CD in with a bit of bass, and although it was noticeable, it just wasn’t great. And if I tried to increase the volume, the sound just got boomy. What have I done wrong??!! Please help me out, I’m desperate!
Let me know if you need more info.
Cheers.
I’ve just finished putting together my Shiva subwoofer and I must say I am a little disappointed.
I must be doing something wrong because I have read so many great reviews on this driver.
So let me re-cap my design:
I have built a 60 liter box as per the shiva design ( I increased the dimensions of the original 54 liter box using a CAD program but the design is still the same.)
I used 25mm MDF for the outside and 16mm MDF for the bracing inside.
I used silicon on every joint after the box was assembled.
I mounted the amplifier externally to the main box and used silicon again to seal the wires from the amplifier to the driver.
The amplifier I am using is a JayCar 150Watt @ 4ohm rating.
I used quite a lot of filling inside the box. I used Dacron (sheets for the internal walls and loose as filling) and basically filled it right up to the clearance point for the driver. This includes the holes cut out in the bracing.
I connected the driver in parallel (refer attached)
Finally, I attached a foam seal to the perimeter of the driver before I screwed it in.
The Result?
Well basically, I hooked it up to my Sony amplifier (5x100 watts) and played a DVD. I adjusted all the settings on my amp and the subwoofer was working. However, the sound sounded boomy and it didn’t seem to have much grunt. There was no punchyness to the sound. I put a music CD in with a bit of bass, and although it was noticeable, it just wasn’t great. And if I tried to increase the volume, the sound just got boomy. What have I done wrong??!! Please help me out, I’m desperate!
Let me know if you need more info.
Cheers.
Attachments
Let the driver loosen up, I bet it still smells brand new 😀
-- Have you tried moving the sub around your listening room? Sub placement is critical.
-- The Jaycar 150W amp is not exactly enough for serious sub duty. Its bass extension is questionable and its frequency response isn't mentioned in Jaycar's site. The higher-spec'd units only have a -3dB extension of 20Hz. I'd say the 150W unit has a 30Hz (perhaps even a 40Hz) subsonic filter. Don't trust Jaycar's tech support on this, at one time 1 or 2 of their amps were advertised with a -3dB of 30Hz; The only way to be sure is to take measurements.
-- Perhaps the amp has a (30Hz) bass boost? It's best to bypass such equalization.
-- Make sure the voice-coil wires are in parallel (to get more output, especially from this particular amp).
You really need a ported box for DVDs. My vented Shiva is not boomy at all, often times builders think a sub is boomy when all they're really hearing is the presence of sub-bass frequencies.
🙂
-- Have you tried moving the sub around your listening room? Sub placement is critical.
-- The Jaycar 150W amp is not exactly enough for serious sub duty. Its bass extension is questionable and its frequency response isn't mentioned in Jaycar's site. The higher-spec'd units only have a -3dB extension of 20Hz. I'd say the 150W unit has a 30Hz (perhaps even a 40Hz) subsonic filter. Don't trust Jaycar's tech support on this, at one time 1 or 2 of their amps were advertised with a -3dB of 30Hz; The only way to be sure is to take measurements.
-- Perhaps the amp has a (30Hz) bass boost? It's best to bypass such equalization.
-- Make sure the voice-coil wires are in parallel (to get more output, especially from this particular amp).
You really need a ported box for DVDs. My vented Shiva is not boomy at all, often times builders think a sub is boomy when all they're really hearing is the presence of sub-bass frequencies.
🙂
f4ier said:
Do you have or can you get a schematic for this puppy?
My 48 litre sealed shiva does just fine -- i'm currently using two channels of an NAD7020 (2x20W) to drive it.
And i'll repeat what has been said before -- the driver does need to break in, room placement is critical.
One other thing. If you push the driver in by hand, how long does it take to return?
dave
Shiva
Are your box vented? (Most "DIY-Shiva's" I have seen are), if so, then try to remove most of your filling, as this slows the response, and make the driver "see" a larger volume box.
Arne K
Are your box vented? (Most "DIY-Shiva's" I have seen are), if so, then try to remove most of your filling, as this slows the response, and make the driver "see" a larger volume box.
Arne K
It will probably blow your budget even more, but its so much easier to figure out what is going on in this situation if you have a sound level meter and a test CD. The problem probably is one of sub placement, assuming you haven't made any major calculation mistakes in the speaker design. Alternatively the settings of the sub amp may be causing problems (ie there may be a boost in effect that is not obvious).
The Tandy meter is probably the best to get, although unfortunately it doesn't have a flat setting, only C and A weightings. I have the digital one and it cost around $130 aussie. You can modify it to give a flat response (Wallan mod) by following Eric Wallin's instruction, which you should be able to find at http://www.gti.net/wallin/audio/rsmeter/33-2050/33-2050.html.
Mick
The Tandy meter is probably the best to get, although unfortunately it doesn't have a flat setting, only C and A weightings. I have the digital one and it cost around $130 aussie. You can modify it to give a flat response (Wallan mod) by following Eric Wallin's instruction, which you should be able to find at http://www.gti.net/wallin/audio/rsmeter/33-2050/33-2050.html.
Mick
Did I say poor?
Ok, I admit it, I paniced.
When I first hooked up the Shiva and didnt get the response I was looking for, instead of trying different things to get it working, I paniced. Sorry guys.
I think my amplifier didnt recognise the sub properly (even though I set SW to yes and my other speakers to small). I changed my audio connection from coaxial to optical (not that it should make a difference)but when I turned this baby on it shook my house down!!🙂
Now i have to fine tune it because it sounds a little overwhelming (what? too much bass?) and ive noiticed how many of you mention how critical room placement is, so I'll toy around with that.
I do have a question though:
I have mounted my amplifier external to the main box as mentioned before. The enclosure for the amplifier isnt much bigger than the amplifier itself. After about an hour of operation, the heat fins get quite warm (about 50 degress C ). Since this enclosure is independant of the main box, should I vent the amplifier enclosure somehow? Is this common practice?
Thanks for the tips.
Ok, I admit it, I paniced.
When I first hooked up the Shiva and didnt get the response I was looking for, instead of trying different things to get it working, I paniced. Sorry guys.
I think my amplifier didnt recognise the sub properly (even though I set SW to yes and my other speakers to small). I changed my audio connection from coaxial to optical (not that it should make a difference)but when I turned this baby on it shook my house down!!🙂
Now i have to fine tune it because it sounds a little overwhelming (what? too much bass?) and ive noiticed how many of you mention how critical room placement is, so I'll toy around with that.
I do have a question though:
I have mounted my amplifier external to the main box as mentioned before. The enclosure for the amplifier isnt much bigger than the amplifier itself. After about an hour of operation, the heat fins get quite warm (about 50 degress C ). Since this enclosure is independant of the main box, should I vent the amplifier enclosure somehow? Is this common practice?
Thanks for the tips.
Dave, I don't have the schematics 🙁
Viper073, venting the amp is surely a good thing. The output devices on the amp will also live longer 🙂
Cheers and enjoy the sub. Next thing you know you're itching for a dual Tempest setup 😀
Viper073, venting the amp is surely a good thing. The output devices on the amp will also live longer 🙂
Cheers and enjoy the sub. Next thing you know you're itching for a dual Tempest setup 😀
I second the thoughts about the amp. I have an EBS shiva and the amp that came with it (Altronics) had a bass roll-off filter that cut out everything below 30Hz. Very bad for a sub amp.
So I wired it directly to an external amp and it is pounding away greatly annoying my neighbours. The external amp is only a 50 watter and this is OK for my room, which is actually very large.
Steve
So I wired it directly to an external amp and it is pounding away greatly annoying my neighbours. The external amp is only a 50 watter and this is OK for my room, which is actually very large.
Steve
Some pics!!
Here are some pics of my Silver Shiva!
The end result:
Shiva 12 inch drvier wired in parallel
JayCar 150w (4ohm) amplifier
Box size: 60 Litres + stuffing (Q just under 0.7)
Cost: About AUD$615
Owner? Although over budget I am extremely happy with the result. You cannot beat this for value for money. A succesful DIY project!🙂
Thanks again guys for all your help.
See you again when I want to go bigger and louder!!😀
Here are some pics of my Silver Shiva!
The end result:
Shiva 12 inch drvier wired in parallel
JayCar 150w (4ohm) amplifier
Box size: 60 Litres + stuffing (Q just under 0.7)
Cost: About AUD$615
Owner? Although over budget I am extremely happy with the result. You cannot beat this for value for money. A succesful DIY project!🙂
Thanks again guys for all your help.
See you again when I want to go bigger and louder!!😀
Attachments
The sides are finished with Aluminium sheets (I wanted stainless steel but there was spare sheets at work so i got them instead)
The feet are actually the ends of two oven handles (again from work) which i cut at the right length, stuck them together with araldite, fixed 3mm wood at the end, screwed the wood to the legs, then screwed the wood to the sub. Turned out alright, i had to put some extra carpet underneath cause the legs are pretty sharp!!
The feet are actually the ends of two oven handles (again from work) which i cut at the right length, stuck them together with araldite, fixed 3mm wood at the end, screwed the wood to the legs, then screwed the wood to the sub. Turned out alright, i had to put some extra carpet underneath cause the legs are pretty sharp!!
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