Thanks Paul & Al.
Both issues raised warrant further investigation.
Bass can be calmed to a certain extent via PEQ in the active XO section but I agree its best if its not there at all.
So I'll build some rough and ready prototypes to see how they test.
I may use just 2 x L22's in each.
I've had a mess with the baffle tilted back and apart from a very minor drop of 2dB from 13.5Khz - 18Khz(the upper range of my testing equipment) its nothing to be concerned about. In fact it looks better than on axis since there was a steady rise from 10Khz to 18Khz.
Both issues raised warrant further investigation.
Bass can be calmed to a certain extent via PEQ in the active XO section but I agree its best if its not there at all.
So I'll build some rough and ready prototypes to see how they test.
I may use just 2 x L22's in each.
I've had a mess with the baffle tilted back and apart from a very minor drop of 2dB from 13.5Khz - 18Khz(the upper range of my testing equipment) its nothing to be concerned about. In fact it looks better than on axis since there was a steady rise from 10Khz to 18Khz.
Looks like it's going to be awesome.
I'm a little worried about your bass-driver impedance. 3xL22s in parallel right? That's hitting close to 2 ohms!
www.gattiweb.com
I'm a little worried about your bass-driver impedance. 3xL22s in parallel right? That's hitting close to 2 ohms!
www.gattiweb.com
Cheers David,
Lovely work on the Delta's too.
To be honest I'm thinking 3 x L22's is somewhat excessive. I've built a single 30ltr cube with just one of L22's in and its deep, very tuneful, reaching flat into the early 30's after which output is negligible.
2 should certainly give me what I'm after and maybe even avoid a subwoofer altogether with a small LT and room gain.
I'm going to try an L22 in another box but with a Q of 0.707 to test the difference between that and the lower Q version I have now.
Hopefully I'll gain a little more speed, power handling and save a little space. I guess I'm not likely to lose a great deal of extension but I just want to be sure before I start work on the real thing.
Lovely work on the Delta's too.
To be honest I'm thinking 3 x L22's is somewhat excessive. I've built a single 30ltr cube with just one of L22's in and its deep, very tuneful, reaching flat into the early 30's after which output is negligible.
2 should certainly give me what I'm after and maybe even avoid a subwoofer altogether with a small LT and room gain.
I'm going to try an L22 in another box but with a Q of 0.707 to test the difference between that and the lower Q version I have now.
Hopefully I'll gain a little more speed, power handling and save a little space. I guess I'm not likely to lose a great deal of extension but I just want to be sure before I start work on the real thing.
vex0rg said:
£10 was sent ages ago, must be 2 weeks now at least.
email me at: shinobiwan3264@hotmail.com and I'll pass along the track number.
Good news.
Just finished cutting virtually all the MDF for the bass section of the cabinet. There's been a few changes.
Firstly I scraped the matrix bracing arrangement as it seems somewhat redundant in a 40ltr enclosure not to mention it was going to swallow a considerable chunk of the volume. Instead I've opted for a heavy duty cross-braced arrangement. Should provide a similar level of stiffness to the originally planned matrix.
After taking onboard what was said about off-axis response re: the scan ring and performing pretty extensive tests with SW, I've made the bass cabinet 10cm shorter so as to better align the tweeter with the ear. I'm now looking at a near perfect flat response from 3Khz-20Khz using measurements made at the listening position with the test open baffles
So it looks very promising.
More importantly I've decided to go with just the two L22's per cabinet. I was intending to build another prototype enclosure to see how one would perform in a higher Q 20ltr enclosure, this of course didn't happen. Instead I choose to simply implement a 0.7Q enclosure with both drivers sharing the same volume of 40ltr and began cutting the necessary bits today. One sounds lovely in the test enclosure so I'm sure I'll be thrilled once I get all four bouncing
Just finished cutting virtually all the MDF for the bass section of the cabinet. There's been a few changes.
Firstly I scraped the matrix bracing arrangement as it seems somewhat redundant in a 40ltr enclosure not to mention it was going to swallow a considerable chunk of the volume. Instead I've opted for a heavy duty cross-braced arrangement. Should provide a similar level of stiffness to the originally planned matrix.
After taking onboard what was said about off-axis response re: the scan ring and performing pretty extensive tests with SW, I've made the bass cabinet 10cm shorter so as to better align the tweeter with the ear. I'm now looking at a near perfect flat response from 3Khz-20Khz using measurements made at the listening position with the test open baffles
So it looks very promising.More importantly I've decided to go with just the two L22's per cabinet. I was intending to build another prototype enclosure to see how one would perform in a higher Q 20ltr enclosure, this of course didn't happen. Instead I choose to simply implement a 0.7Q enclosure with both drivers sharing the same volume of 40ltr and began cutting the necessary bits today. One sounds lovely in the test enclosure so I'm sure I'll be thrilled once I get all four bouncing
Great to hear of your progress.
Are you using MDF or plywood? What thickness?
I used MDF but in retrospect the greater rigidity of plywood may have been a better choice for the woofer enclosure. I'm going to add some more bracing now that I have them apart.
Hopefully we'll see some pics soon.
David
Are you using MDF or plywood? What thickness?
I used MDF but in retrospect the greater rigidity of plywood may have been a better choice for the woofer enclosure. I'm going to add some more bracing now that I have them apart.
Hopefully we'll see some pics soon.
David
edjosh23 said:
Nothing really interesting to show at the moment.
Here's one of the MDF for the bass cabinets all cut and ready routing then assembly:
An externally hosted image should be here but it was not working when we last tested it.
And here's one of the real brains behind the operation
An externally hosted image should be here but it was not working when we last tested it.
Well its been a busy time around here.
The lower cabinet sections have been started and I hope to get a few pics of them soon for you.
One of the reasons for the lack of response has been because I've now chosen some different amps to the ones originally planned. The new ones are from ESP and namely the P101 which is based on Hitachi lateral MOSFET's.
This has meant a lot of seaching and research for parts and finally a short wait for them to arrive.
I've just completed 1 of the 6 boards required and again will post a photo or two with the other's.
Hope everyone in the UK had a good bank holiday weekend too!
The lower cabinet sections have been started and I hope to get a few pics of them soon for you.
One of the reasons for the lack of response has been because I've now chosen some different amps to the ones originally planned. The new ones are from ESP and namely the P101 which is based on Hitachi lateral MOSFET's.
This has meant a lot of seaching and research for parts and finally a short wait for them to arrive.
I've just completed 1 of the 6 boards required and again will post a photo or two with the other's.
Hope everyone in the UK had a good bank holiday weekend too!
OK heres the pics and info so far:
Shots of the amps, one for the Scan Ring, one for the ATC and one shared between the 2 Seas. So that's 3 amps per cab.
4 of the amps/the ones that drive the treble and midrange feature Blackgate capacitors for maximum performance, these aren't cheap at £4 each but thank fully I only needed 8 for the 4 boards.
The other two without Blackgates feature standard caps but all other components are the same ie. high quality and the best I could realistically afford. These two amps are used for the bass section.
Lastly, the board with the heatsink attached and has the 8 capacitors is one of the 15v regulated PSU's for the XO's and associated bits. The two black round things are mini toroidals used for the 15v PSU's.
Not bad for my first attempt at PCB construction - haven't tested them yet though :lol: Also some boards don't quite have all the components soldered into place yet.
More info on the amps is here:
http://www.sound.westhost.com/project101.htm
Shot showing the amps and the heatsinks needed to cool all that power(True 600w RMS into 8ohm each side).
Shot of the brushed aluminium rear panels. One to be used for each box or 4 in total. Still need to be cut but will hold the IEC mains plug, switch, fuse, RCA input, XLR input and the umbilical between the sub and sat.
Plenty of stuffing for the sealed bass section of the lambswool variety. Apparently if you use lambswool you gain another 2hz extension or at least that's what I read in What-Hifi
Not shown is a ton a self adhesive lead bitumen sheets for deadening the cabinets.
All the internal bracing for bass cabinets cut and ready for fitting.
Pictures of the bass cabinet which are coming along nicely. Note the two smallish compartments to the rear of the speaker, these will house the amps and other electronics. These will also be 'skinned' in 10mm MDF to add rigidity and also to cover up the screw and joints, the edges of this 10mm MDF will be trimmed at 45 degrees to form shamfered edges and also provide a joint free cabinet. Bracing still to be fitted and then the internals will be sealed with 40/50 water/PVA mix and finally the dedshete panels and lambswool will be added.
All the MDF for the bass cabinet skinning is ready cut so they should go up in no time. Its the sats that's got my attention as the minute though.
Some shots of the sats in a very early constuction stage. You wouldn't believe the level difficulty building these things. I'll tell you that if your going to do any cabinet with lots of angles then do yourself and your sanity a favour and buy the best equipment that you can afford. I was trying to do all this with a £120 Wickes bench saw and it was woefully inadequate, with lots of wasted MDF and cursing. Just was not accurate enough in the way that when you set it to 8 degree bevel it clearly wasn't that and even though the margin of error was very small you need incredible accuracy for this type of work.
As luck would have it my old man is a joiner by trade and was on the look out for a new mitre saw, so I went went halves and we doubled our budget for one. In the end we went for the a Bosch GCM10SD as shown here:
[url]http://www.tooled-up.com/Product.asp?Referrer=IndexSite&
£500 is a hell of a lot of money for something as joyless as a power tool but let me tell that this thing is an absolute pleasure to work on. Accurate cuts everytime and now I really do believe in the old saying 'your only as good as your tools'. Complicated jobs require good machinery. Future project should be made much easier with this tool, that is if I can stop dad nicking it first, we'll have to do a time-share thing
Lots more to do over the coming weeks and I'll get back here with pictures when I have them.
Comments, suggestion and questions welcomed.
An externally hosted image should be here but it was not working when we last tested it.
Shots of the amps, one for the Scan Ring, one for the ATC and one shared between the 2 Seas. So that's 3 amps per cab.
4 of the amps/the ones that drive the treble and midrange feature Blackgate capacitors for maximum performance, these aren't cheap at £4 each but thank fully I only needed 8 for the 4 boards.
The other two without Blackgates feature standard caps but all other components are the same ie. high quality and the best I could realistically afford. These two amps are used for the bass section.
Lastly, the board with the heatsink attached and has the 8 capacitors is one of the 15v regulated PSU's for the XO's and associated bits. The two black round things are mini toroidals used for the 15v PSU's.
Not bad for my first attempt at PCB construction - haven't tested them yet though :lol: Also some boards don't quite have all the components soldered into place yet.
More info on the amps is here:
http://www.sound.westhost.com/project101.htm
An externally hosted image should be here but it was not working when we last tested it.
Shot showing the amps and the heatsinks needed to cool all that power(True 600w RMS into 8ohm each side).
An externally hosted image should be here but it was not working when we last tested it.
Shot of the brushed aluminium rear panels. One to be used for each box or 4 in total. Still need to be cut but will hold the IEC mains plug, switch, fuse, RCA input, XLR input and the umbilical between the sub and sat.
An externally hosted image should be here but it was not working when we last tested it.
Plenty of stuffing for the sealed bass section of the lambswool variety. Apparently if you use lambswool you gain another 2hz extension or at least that's what I read in What-Hifi
Not shown is a ton a self adhesive lead bitumen sheets for deadening the cabinets.
An externally hosted image should be here but it was not working when we last tested it.
All the internal bracing for bass cabinets cut and ready for fitting.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Pictures of the bass cabinet which are coming along nicely. Note the two smallish compartments to the rear of the speaker, these will house the amps and other electronics. These will also be 'skinned' in 10mm MDF to add rigidity and also to cover up the screw and joints, the edges of this 10mm MDF will be trimmed at 45 degrees to form shamfered edges and also provide a joint free cabinet. Bracing still to be fitted and then the internals will be sealed with 40/50 water/PVA mix and finally the dedshete panels and lambswool will be added.
An externally hosted image should be here but it was not working when we last tested it.
All the MDF for the bass cabinet skinning is ready cut so they should go up in no time. Its the sats that's got my attention as the minute though.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Some shots of the sats in a very early constuction stage. You wouldn't believe the level difficulty building these things. I'll tell you that if your going to do any cabinet with lots of angles then do yourself and your sanity a favour and buy the best equipment that you can afford. I was trying to do all this with a £120 Wickes bench saw and it was woefully inadequate, with lots of wasted MDF and cursing. Just was not accurate enough in the way that when you set it to 8 degree bevel it clearly wasn't that and even though the margin of error was very small you need incredible accuracy for this type of work.
As luck would have it my old man is a joiner by trade and was on the look out for a new mitre saw, so I went went halves and we doubled our budget for one. In the end we went for the a Bosch GCM10SD as shown here:
[url]http://www.tooled-up.com/Product.asp?Referrer=IndexSite&
£500 is a hell of a lot of money for something as joyless as a power tool but let me tell that this thing is an absolute pleasure to work on. Accurate cuts everytime and now I really do believe in the old saying 'your only as good as your tools'. Complicated jobs require good machinery. Future project should be made much easier with this tool, that is if I can stop dad nicking it first, we'll have to do a time-share thing
Lots more to do over the coming weeks and I'll get back here with pictures when I have them.
Comments, suggestion and questions welcomed.
An externally hosted image should be here but it was not working when we last tested it.
The Seas L22-RN4X/P 8" bass drivers arrived today
An externally hosted image should be here but it was not working when we last tested it.
The sats are comming along or at least one of them is
An externally hosted image should be here but it was not working when we last tested it.
The box looks kind of a mess with all the translam baffle and other joints so I modified the photo with a vector drawing program to try to highlight the actual shape once sanding, filling and spraying has taken place.
An externally hosted image should be here but it was not working when we last tested it.
Rearward view, this side as had the bevel added to some of the edges. Also notice the green automotive bodyfiller, I cocked up with the mitre saw and needed to hide the scars
Personally I'm unsure about the 'look' of the front baffle. I would really appreciate any feedback on the overall look.
David Gatti said:
Long story but its an old habbit from my car audio days. Every box I built I sealed the inards to prevent expansion of the MDF. So its force of habbit really, some say its not needed for home audio since its not exposed to air moisture like a car audio setup, I say it doesn't hurt.
You should of course definitely seal the external parts on every occassion when using MDF.
m0tion said:
Well each amp will have its own seperate heatsink (0.5w disp.) making 3 per cabinet and these heatsinks will be mounted externally to the rear and I'm hoping to find someone who will cut an aluminium plate to size for this job. The bottom most section in the photo above will house the amps, respective PSU and 1000VA Toroidal, the top section will house the XO, LT circuit, all-pass and and the associated PSU.
All connection will be placed on an aluminium plate and then mounted on the angled part of the sub&sat to the rear, these connections will be IEC power socket(switched&fused), balanced XLR input, unbalanced RCA input and umbilical between the sat and the sub.
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