View Full Version : Acoustic Solutions AV21 speaker rebuild
In the very near future there should be a lot more DIY activity going on here at Synsei Towers so in preparation I needed a sacrificial lamb to practice upon, which is where the speakers in the thread title come in.
http://matrixdiscounts.co.uk/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/a/v/av21_1_3.jpg
Bought around nine years ago from Argos for the princely sum of £19.99 to upgrade the front L/R speakers of a surround sound speaker system manufactured by the same company, amazingly for the price they are equipped with a 130mm long throw woofer and a dome tweeter of dubious origin. The plan is for me to see how far I can take them via the employment of some judicious upgrade mods. I'm not expecting miracles as the cabinets are very cheaply made but with luck ,and if all goes well, by the end of the project I will have acquired some extra knowledge and skills, and just maybe, have a passable sounding pair of small speakers to use elsewhere in the house.
To begin with these three mods should be very easy to carry out:
1: Rewire with Van Damme Blue, 1.5mm twisted core speaker cable.
2: Line the inside of the cabs with sound-deadening material to reduce the rather tuneful 'thwok' which is produced when one raps the sides with a knuckle.
3: Replace the cheap and nasty spring type speaker terminals with 4mm binding posts (nothing too fancy mind, they don't really warrant it)
If all goes well with the above, and I don't see any reason why it shouldn't, I may consider replacing the current driver line-up and crossover with better quality items a little further down the road. If you have any ideas yourself please feel free to contribute them :smoking:
istari_knight
14-07-2014, 20:56
If you have a peek at the crossovers and note capacitor value's I might have some suitable film replacements you'd be welcome to Dave.
If you have a peek at the crossovers and note capacitor value's I might have some suitable film replacements you'd be welcome to Dave.
Your on the ball aren't you James, just taken some piccies of the x-overs as it happens, I'll post them up shortly :)
istari_knight
14-07-2014, 21:20
:D
I can't promise I've got what you'll need but worth a check eh !
http://i1019.photobucket.com/albums/af316/Sgtgrash/Hifi%20Stuff/2014-07-14215439.jpg (http://s1019.photobucket.com/user/Sgtgrash/media/Hifi%20Stuff/2014-07-14215439.jpg.html)http://i1019.photobucket.com/albums/af316/Sgtgrash/Hifi%20Stuff/2014-07-14215036.jpg (http://s1019.photobucket.com/user/Sgtgrash/media/Hifi%20Stuff/2014-07-14215036.jpg.html)http://i1019.photobucket.com/albums/af316/Sgtgrash/Hifi%20Stuff/2014-07-14214928.jpg (http://s1019.photobucket.com/user/Sgtgrash/media/Hifi%20Stuff/2014-07-14214928.jpg.html)http://i1019.photobucket.com/albums/af316/Sgtgrash/Hifi%20Stuff/2014-07-14215122.jpg (http://s1019.photobucket.com/user/Sgtgrash/media/Hifi%20Stuff/2014-07-14215122.jpg.html)
I'll take some clearer photos tomorrow, the flash is too strong in these to make much out.
Just two components on the x-over board, a 100v 2.2uF electrolytic and a 5v 1ohm resistor :)
istari_knight
14-07-2014, 21:41
Thats okay, no need for clearer photo's dude... Not much in there is it ?! Thats a 1st order filter on the tweeter with a series resistor to drop output level and bring it in line with the midbass, the midbass is run full range. Unusual but not unheard of... There's some DIY efforts "elsewhere" where they have been adding steel plate to the internal cabinet walls of mini JPW's which is what most of the top Royds had back in the day, it does add a real snap to the sound.
I think I've got some 2.2uF's, will have a look tomorrow might even have some decent mox resistors :hmm:
Afore you go a'meandering into your parts cellar, is there anything which can be done to improve the x-over that a lummox like me might be able to grasp, even if it means hardwiring bits 'n' pieces to stuff? ;)
istari_knight
14-07-2014, 22:07
Well, it depends on what school of thought you follow. The KeepItSimpleStupid crowd would say the stock arrangement is the best way of doing it... It really doesn't get any simpler than that !
You could experiment with the resistor value which would give a brighter / duller balance depending on which way you go.
Gettin' a bit ahead of myself perhaps, probably best to try the minor mods first to see what improvements can be wrought there. Adding steel to the inside of the cabs might be a little beyond the remit of the project really. I have no means to cut steel here plus I'd rather not throw too much money at them if I can help it, this is more an educational project with a slight chance of a surprising ending. If you do happen to have the components you mention send me a PM, I'll pay a fair price for them dude. if not, then I'll source some on t'interweb.
I took a close look at the existing wiring whilst I was inside the cabs and it's fairly chunky stuff, 1.5mm multistrand like the Van Damme, though with less strands. Actually the build quality of these units is, on the whole, pretty decent. Acoustic Solutions are based not too far away from me as it happens, in Weedon, Northamptonshire :)
istari_knight
14-07-2014, 22:36
Yeah thats a fair shout, it was just an idea I thought worth mentioning. They certainly look fairly well made, for £20 AS profit margins be small.
Should make for a fun little project & the experience gained will really boost your confidence for tackling the B&W's. I'll have a look and get back to you tomorrow on the parts :)
awkwardbydesign
15-07-2014, 07:59
Adding steel to the inside of the cabs might be a little beyond the remit of the project really. I have no means to cut steel here plus I'd rather not throw too much money at them if I can help it, this is more an educational project with a slight chance of a surprising ending.
You could buy a metre of threaded steel bar (8mm?) from B&Q, cut it to just shy of the inner width and height of the cabs, put a nut on each end and tighten (not too much!) across the cabs to brace them. I use this method quite a lot, you can even tune them. If you can't get them into the cabs, drill a 8mm hole in one end/side and slide them through. On big drivers I sometimes brace the back of the magnet too. Use a small piece of hardboard or similar at the end of the bar, and spring or shake proof washers.
I like the threaded bar idea Richard plus it will be easier to work with, thanks for that :)
walpurgis
15-07-2014, 09:10
I'd be careful with steel bar, depending on placement it may interact with the driver magnets and crossover inductors. For simple cross bracing I just use a length of square wood glued across. Never had one come loose, it's light and works.
Good point Geoff. There's not a lot of room in the cabs as they are so wee so yours is probably the best option. I'll rummage around in the garage for a wood offcut, there's bound to be sommat I can use in there :)
istari_knight
15-07-2014, 15:12
Sorry Dave, I've been rummaging but can only locate one of my parts boxes which contains nothing relevant :(
Not sure where to suggest you buy crossover parts from, audio-components.co.uk are good on a budget as orders £10 or above have free p&p... hificollective & falcon acoustics charge £5 p&p regardless of how much you purchase.
No worries James, perhaps ebay could help there, I'll take a looksie. Thanks for having a gander dude ;)
awkwardbydesign
15-07-2014, 17:16
I'd be careful with steel bar, depending on placement it may interact with the driver magnets and crossover inductors. For simple cross bracing I just use a length of square wood glued across. Never had one come loose, it's light and works.
What inductors? :lol: And not sure if it would bother the speaker, after all shielded speakers have a steel cup around the magnet. The advantage (to me) of the steel bar method is 1) It's tunable and 2) It's removable. In my present bass cabinets the 12mm bar is accessable from the back and has a slotted head to adjust it.
walpurgis
15-07-2014, 19:58
What inductors? :lol: And not sure if it would bother the speaker, after all shielded speakers have a steel cup around the magnet. The advantage (to me) of the steel bar method is 1) It's tunable and 2) It's removable. In my present bass cabinets the 12mm bar is accessable from the back and has a slotted head to adjust it.
Ah, quite so. I hadn't paid attention to the crossover photo. I don't know if these speakers use 'canned' magnets.
awkwardbydesign
15-07-2014, 20:00
I doubt it at that price.
They certainly do, if by 'canned' you mean shielded? ;)
istari_knight
15-07-2014, 20:10
One would hope so considering their primary use is supposed to be in AV systems :lol:
awkwardbydesign
16-07-2014, 07:25
A bargain then. And a steel bar wouldn't cause problems, surely?
I have these hooked up to the main system just now to gauge their unmodified performance characteristics and I have to say they sound pretty good, taking into account their design limitations and the pittance I paid for them. Granted, they won't trouble a pair of LS3/5a's or even a pair of JPW Gold mini-monitors but I am tapping my feet and bobbing my head along to Massive Attack's Mezzanine just now so they must be doing something right. They definitely have a 'character' however. Midrange is a bit in-your-face and obviously deep bass is non-existent. Kick drums sound a wee bit boxy and enclosed but generally what I am hearing is a clean, musical presentation with fabulous pin sharp imaging and a decently wide soundstage which is a tad two dimensional as there is limited depth to the image. It's there but not all that prominent. Turn the wick up and the tiny bass/mids leap into life and try their damndest to offer a sense of scale to proceedings and on the whole they succeed admirably. Frankly I am astounded twenty pounds can buy you this level of performance, well done AS ;)
P.S. Oh almost forgot. The top end is crisp, there's a fairly decent tweeter in there...
Just shows even a cheap, simple speaker will sound acceptable, even enjoyable, if you can feed it a decent signal.
You should think big. Use them as the mid and treble pod of a three-way. You just need to build two big bass cab and stick a fifteen in each one. ;)
Just shows even a cheap, simple speaker will sound acceptable, even enjoyable, if you can feed it a decent signal.
You should think big. Use them as the mid and treble pod of a three-way. You just need to build two big bass cab and stick a fifteen in each one. ;)
Might have the chance to do that too, I have been promised two, professional, twelve inch Celestion bass drivers for nought. Perhaps they might prove useful... ;)
Serendipity. You can't let that go by....
The Grand Wazoo
19-07-2014, 23:05
Bracing with broomsticks? Drill holes in cabinets?
You must be kidding!
This is how you do it.
http://imageshack.us/a/img191/4529/durt.jpg
See my thread here (http://theartofsound.net/forum/showthread.php?27501-Genexxa-Pro-LX5-Speakers-Tart-em-up-or-Chuck-em-out!)
I don't charge (too) much for a licence to use my brilliant solution.
Primalsea
20-07-2014, 08:32
My parents have a pair of AS AV20 and I always thought they sounded pretty good. Not exactly tonally neutral but quite musical and not unpleasant at all.
Bracing with broomsticks? Drill holes in cabinets?
You must be kidding!
This is how you do it.
http://imageshack.us/a/img191/4529/durt.jpg
See my thread here (http://theartofsound.net/forum/showthread.php?27501-Genexxa-Pro-LX5-Speakers-Tart-em-up-or-Chuck-em-out!)
I don't charge (too) much for a licence to use my brilliant solution.
Now THAT is an elegant 'acoustic solution' (:)) for cab bracing which also neatly sidesteps an issue I have with limited access to the interior of the cabs. Nice one Chris, thank you :)
The Grand Wazoo
20-07-2014, 09:20
That's the beauty of it, you can get it all through a bass driver sized hole in the cabinet, then make it fit & tighten up.
My parents have a pair of AS AV20 and I always thought they sounded pretty good. Not exactly tonally neutral but quite musical and not unpleasant at all.
My experience exactly which is why I reckon it is worth lavishing a little time and effort on them to discover further hidden potential.
http://i1019.photobucket.com/albums/af316/Sgtgrash/Hifi%20Stuff/ffe38c23-a8fd-41c3-bf49-15b2de9ea6d5.jpg (http://s1019.photobucket.com/user/Sgtgrash/media/Hifi%20Stuff/ffe38c23-a8fd-41c3-bf49-15b2de9ea6d5.jpg.html)
I now have these hooked up to a JVC AX-A3 integrated amp which I employ for headphone duties, driven via the unattenuated output from my BTE passive, a task at which it excels. Well, it is no fluke, the AV 21's sound just as musical hooked up to a more modest amplifier. The more I hear the more convinced I am that there is a fine speaker system here just bursting to be set free. Loving the suggestions so far folks, keep 'em coming ;)
Having given Chris' bracing idea some thought I have decided to use steel pads instead of items cut from wood. My thinking here is that over time the pressure will drive the ends into the wood thus loosening the brace and allowing it to vibrate. Because I can get away with using a thinner section with steel this will also mean less intrusion into the cabs to affect the internal volume, does that make sense? :scratch:
There's some DIY efforts "elsewhere" where they have been adding steel plate to the internal cabinet walls of mini JPW's which is what most of the top Royds had back in the day, it does add a real snap to the sound.:
Been giving this idea some thought James and I may be able to do this using short steel strips epoxied horizontally down the inside walls of the cab sides. This would keep the lengths short and thus enable me to manoeuvre them more easily into place via the driver cut-outs. Also, I can kill two birds with one stone as the resulting steel surface would be a good solid seat for two of these (http://www.rosscastors.co.uk/adjustable-feet/economy-stainless-steel-feet.html) connected together with one of those (http://www.tlc-direct.co.uk/Products/UVCO2.html) ;)
Stephen (Mr Kipling) is kindly sending me some Panasonic 2.2uF film caps to try out in the crossovers (thank you muchly Stephen). Just need a bit of advice as to which resistors to use now or should I stick with the original items?
istari_knight
20-07-2014, 20:49
Been giving this idea some thought James and I may be able to do this using short steel strips epoxied horizontally down the inside walls of the cab sides. This would keep the lengths short and thus enable me to manoeuvre them more easily into place via the driver cut-outs. Also, I can kill two birds with one stone as the resulting steel surface would be a good solid seat for two of these (http://www.rosscastors.co.uk/adjustable-feet/economy-stainless-steel-feet.html) connected together with one of those (http://www.tlc-direct.co.uk/Products/UVCO2.html) ;)
Sorry, I missed this - Sounds like a plan :thumbsup:
I have 4 x 12W 4.7R MOX resistors you're more than welcome to but they would need paralleling to achieve 2.35R which might be too much. PM me if interested.
First 2.2uF cap fitted in one of the AV21's. More later... ;)
http://i1019.photobucket.com/albums/af316/Sgtgrash/Hifi%20Stuff/0ec5e4ae-d6b8-4e3e-9237-913e5aa6a6fa.jpg (http://s1019.photobucket.com/user/Sgtgrash/media/Hifi%20Stuff/0ec5e4ae-d6b8-4e3e-9237-913e5aa6a6fa.jpg.html)
argh the suspense is killing me :more:
brian2957
09-08-2014, 14:41
:popcorn:
Life intervened as is its wont. I may do the other one this evening but more likely to be tomorrow now. The one I have done sounds pretty good however I shall have a clearer picture once work on both is complete. Do film capacitors bed in over time btw?
Now done and sounding fab. Initially I thought I wouldn't need to replace the resistors on the crossovers but not so sure now after a little more listening time. I'll see how things pan out over the next couple of days...
http://i1019.photobucket.com/albums/af316/Sgtgrash/Hifi%20Stuff/0ec5e4ae-d6b8-4e3e-9237-913e5aa6a6fa.jpg
I wasn't happy with the cap on top of the board (above) as it looks untidy, so I've moved them both to the back of the board where they can't foul anything and look a whole lot neater :)
I had these little buggers open again today for more surgery. Into each speaker went a Mundorf 1r resistor and an Elna cap of some description (James, help me out here!!! :lol:). All solder joints on the crossover boards have been re-soldered with silver solder and the speakers have now been up and running for around an hour and a half and they sound amazing. Next up will be a complete rewire with some Van Damme 1.5mm cable but not today as my back is buggered, hence why there are no photos, sorry chaps...
spotify:album:3eiqFPI86vrdpzHuKM9KTP
The album above is playing currently and wow, there is such presence in this recording using the AV21's. I know I keep banging on about this but it is worth restating that these tiny speakers cost me just £19.99 from Argos... :stalks:
brian2957
06-09-2014, 17:44
Aye we like the photies matey :lol: . Sounds like you're on the right track Dave . You have PM mate.
istari_knight
06-09-2014, 18:01
(James, help me out here!!! :lol:)
:)
Dave upgraded the stock ceramic wirewound resistors [look like white coffins] to audiophile approved Mundorf M-Resist [metal oxide.]
http://www.hificollective.co.uk/images2/mresist_mr5_350.gif
He also "upgraded" the stock Chinese no-name bipolar 'lytics to some basic films but didn't like the resultant sound so has now fitted some Elna RBD bipolar 'lytics.
http://www.hificollective.co.uk/images/elna_rbd_300.gif
He also has some Mundorf E-Caps which I guess might be rolled in at some point... Or not if the Elna's keep doing the business ;)
http://www.hificollective.co.uk/images2/mundorfac350.jpg
Thanks James, I'm in so much pain now that it is affecting my concentration. This is not an expensive upgrade considering the considerable improvement in SQ, there is such presence apparent now. I've just put on Talk Talk's the Colour Of Spring and honestly, I have never heard this album sound so good. There is so much texture to everything, it really is quite staggeringly brilliant. I want to run with this now to see where it will lead as I think there is more to come, watch this space...
Well, I won't be rewiring the 21's tweeters easily. Having removed them yesterday (which was a complete faff btw) the extent of the budget 'lavished' on their design and manufacture was starkly revealed. Plastic faceplates (nothing new here and what I expected tbh) but it is to the rear of the driver where things aren't so hot. Thin metal strips held by cheap plastic supports moulded into the tweeter housing feed the coil, the cable end is fitted with the cheapest looking spade connectors I have ever clapped eyes on. Upon trying to remove the cables the entire housing deformed alarmingly. If I go near it with a soldering iron I worry that the entire shebang will end up as a puddle of molten plastic on the bench. I'm too much of a wuss to go anywhere near the bass/mids just now for fear of discovering even more horrors... :lol:
walpurgis
08-09-2014, 22:29
If you're going near plastic whilst soldering, the idea is to use a properly hot iron with solder on it and a quick dab with the iron once the wire is in place. Use Blutak on the insulation to hold the wire where you need it. Some good soldering flux applied to the join area first should help with a quick job.
If you're going near plastic whilst soldering, the idea is to use a properly hot iron with solder on it and a quick dab with the iron once the wire is in place. Use Blutak on the insulation to hold the wire where you need it. Some good soldering flux applied to the join area first should help with a quick job.
Cheers for the tip Geoff although to be honest I'm considering leaving the tweeter cables well alone and just upgrading those to the bass/mids with 1.5mm Van Damme... ;)
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