"speakers wot I made" Tenson

Discussion in 'DIY Discussion' started by pat36a, Apr 4, 2008.

  1. pat36a

    pat36a

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    Can anyone provide further details with regard to the following post which was found on the "world Designs" forum. I have been considering some Arros, so the thought of making something "better" has caught my interest.


    VantheMan27th August 2007, 08:01 PM
    Just a quickie to say thanks to all those who bore with my pathetic questions regarding rebating drivers and the nitty gritty of external crossovers etc. etc.
    I have just finished the MK1 version of my boxes based on the Seas coaxials and I am very, very impressed. I had no previous experience and I went for the design by a Guy on the zerogain forum (thread called "speakers wot I made) called Tenson because it was so simple even to this simpleton. Basically they are a great improvement over my 5 year old Totem Arros which have served me very well but since I upgraded from Sugden A21a to the A21SE they had seemed a little puny. These new boxes ,admittedly much larger, actually move the air in my room while, if anything, improving on the pin point stereo image, detail and sparkle that my arros had always displayed.
    Mk1 version ??? yes, I'm going to make some new boxes, slightly shorter but respecting the baffle step and port size arrangement and Tenson is working on the final version of his crossover.
    I now see that by making your own boxes and thanks to some clever people willing to share their knowledge and experience, you can not only save a lot of cash but also extract a certain gut feeling of "je ne sais quoi" that comes from actually having made something that really works.
    Thanks again to one and all.
    Chris
     
    pat36a, Apr 4, 2008
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  2. pat36a

    Telkman Nurturing Malevolence

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    Telkman, Apr 4, 2008
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  3. pat36a

    pat36a

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    Thanks for the quick response.

    I'm tempted, so very tempted!

    My DIY skills are OK, but not really done any speaker building or serious circuit work before - so might need a little help along the way.

    The first of many questions:

    Why put the tweeter at the back?

    Where would I source the driver and tweeter?

    What do you use as wire/cable between the xover components?
     
    pat36a, Apr 4, 2008
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  4. pat36a

    zanash

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    ok ......here goes

    tweeter on the back reflects off the rear wall adding a time lag compared with the woofer.

    dispersion off the rear wall gives a bigger treble footprint and may add ambiance ?

    the reflected treble is 180 deg out of phase ....

    thats all I can think of straight away

    drivers ..try wilmslow audio

    what internal wire ?.......thats a good question ....try a single core from 15amp twin and earth [use one of the insulated cores!]

    I'm certain tenson can answer you better pm him
     
    zanash, Apr 4, 2008
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  5. pat36a

    Tenson Moderator

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    Hi Pat,

    That speaker design went through many stages before finally arriving at what I have now (being used by a friend in his home studio).

    I should probably edit that original thread so not to mislead people with the designs I found were not so good.

    As you will see if you read all the way through, I went for a few different crossover versions getting more complex along the way. My main issue was that the lower midrange seemed to lack a bit of definition (though I am used to really top quality speakers) and I kept trying to re-jiggle things to resolve that perception.

    I found that in the end what was needed was a sealed (i.e. not ported) cabinet. I suspect this helped because the sealed air acts as a cushion and gives the driver a resistance to work against. Having moved the design over to a sealed box, the crossover went right back to basics of just one component for the woofer and one for the tweeter, and it works really very nicely. They sound a lot better (IMO) than the Ascendo C5 which is a similar design, only ported, and costs about £1.5K :)

    The trade-off of a closed box design is less bass extension (though it rolls-off earlier, it does it slower). For my friend I changed the design to a standmount, but there is no reason you can not make a floorstanding design of the same width and use the same components, resulting in the same sound just with deeper bass. The design was 17cm wide, which meant it was really as narrow as it could get. You could get away with about 3-4cm extra width if you wanted to, and make them as tall and deep as you like. A 30 liter internal volume seems pretty suitable for in-room bass to 40Hz.

    Here is the final xover design and in-room measured response.

    [​IMG]

    Here is the speaker that my friend is now using happily (and it does sound rather good!) :)

    [​IMG]
    [​IMG]
    Yes, there was a bit of smog that day.

    That cabinet was 17 x 28 x 25cm WHD, and made with 18mm MDF. All walls of the cabinet were lined with 50mm rockwool (careful attention paid to surrounding the driver on all sides to reduce reflections). The driver cutouts were, outer cutout 17.6cm, internal cutout 15cm.

    To answer your original questions, the tweeter on the back was to work in conjunction with the one built in to the center of the woofer. It was to be lower in level and simply add some 'air' to the sound via diffused reflections off the back wall. The floorstanding Ascendo C7 does this, which is why I thought I would try it. After about 15mins of playing with it I junked the idea. It works best using just the coaxial woofer and tweeter unit, or the balance gets a bit messed around.

    For internal wire I used 2 core stranded mains cable (the orange stuff from B&Q). I don't like twin and earth (the stuff for in-wall wiring in the house) as it is too thick and heavy and breaks off at the solder joints if you try and move things too much. In fact for the Xover components I connected them directly to the woofer and tweeter terminals since there is only one part for each, and the wire from the back of the speaker terminals then connected to those. Basically do what you like, it makes little difference as long as the damn thing is connected up. Zanash would disagree, being the cable loving man he is! :D

    I got my drivers from Solen, as I have a trade account. If you are in the UK talk to Peter at www.seas.co.uk and he will no doubt be able to sort you out, as he is the Seas UK distributor I think. You should also be able to get the xover parts from the seas website.

    I think that answers all :)
     
    Last edited by a moderator: Apr 4, 2008
    Tenson, Apr 4, 2008
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  6. pat36a

    zanash

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    ah .....nearly right ...didn't realise it was a dual cone
     
    zanash, Apr 5, 2008
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  7. pat36a

    pat36a

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    Thanks guys.

    Seems like a good project to get my teeth into - hope I can motivate myself enough to get started.
     
    pat36a, Apr 6, 2008
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  8. pat36a

    Telkman Nurturing Malevolence

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    Keep us up to date with your progress, Pat! :)
     
    Telkman, Apr 6, 2008
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  9. pat36a

    Chris

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    Did someone mention my name ?

    Well, I am the fumbling first-time DIY novice you mention, who had a punt at Tenson's design to replace my Arros. That was last summer and after being impressed by my first and far from finished effort I was about to embark on making the definitive boxes for same when I read about the Peter Comeau designed sealed box WD20s on World Design. These used the same coaxials in a sealed box design along with matching Seas bass drivers to reinforce the bass response. Well, I have always fancied sealed boxes so I sent off for the extra drivers and components and as this design involved a sandwich particle board/MDF skinned box and my wife being an interior designer and therefore with contacts in the trade, I had the idea of getting the outer skins professionally veneered and finished to hide my pathetic carpentry skills as vented on the partcile board inners. Great idea I said , but criminally slow ( Manana as we say in Spain, I am still waiting) so last month, tired of waiting I went ahead and butchered the Tenson design boxes (similar internal volume but 18mm MDF throughout) on which I hadn't glued the final side down, took out all the baffle step stuff, stuffing etc., stuck in the second driver and sealed the port after placing 3 internal braces, the centre one being "aperiodically vented" as in the WD20 design. All this is very makeshift I stress but I am very pleased with the results so far. The bass has tightened up as was to be expected but the pin-point stereo of the coaxials is really special and they really do just seem to disappear. I hope that when the definitive boxes are finally assembled - Peter Comeau does say they won't sound right if made out of MDF only - they will sound even better.
     
    Chris, Apr 10, 2008
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  10. pat36a

    Tenson Moderator

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    It makes some sense to have the dedicated bass driver since the coaxial doesn't go very deep without porting, but it obviously does add complication.

    On which note, I wouldn't advise many people to copy my standmount design above, since it basically has no bass. This was intentional for my friends very small room, but for most people I'd go straight for the floorstanding sealed enclosure. It will have reasonably well extended, very high quality bass, and will sound very good indeed in the mid and treble, especially for an oh-so-simple design. If you are a first time DIYer its a no-brainer, as they say. Far better than the single full range driver speakers that are otherwise quite common for first builds.
     
    Tenson, Apr 10, 2008
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  11. pat36a

    Chris

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    Couldn't agree more with Simon (Hi and thanks again for being so patient) about it being a no-brainer for novices. Even I managed to get a result.
     
    Chris, Apr 11, 2008
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