First Speaker Project - Basic rules?

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Andy Graddon said:


We can't get the TB drivers down here, (D'archer carries a few, but not the 5.5) and the import freight cost is silly !!

If 'Wired' can get "trade" with WES, that is really the only sensible way to proceed, which means using DST driver (Vifa, Peerless, etc)

Ok then, but I still stick to my suggestion of 2.5way with double 5.5"
 
wiredmonkey said:
Well considering I've never built a speaker before I don't think there is any other word but newbie :)

As for the crossover I think I *should* okay - I understand theconcept of rolloff, different types of filters, decibels, components quality, inductance...etc.

I see a lot of posts regarding the difficulty of crossovers. In my possibly arrogant mind I don't see why they should be difficult - what are the main factors I should take into account other than rolloff and crossover point?


Hi,

Crossovers are incredibly easy to get wrong due to incorrect assumptions.

An unknown design, even for someone like myself, I think, will teach me much more

Short answer to that - generally it does not at all.
The research and selection process of a design done properly will
teach you far more. But if you do want to do it properly start here :

http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spkrbldg/

If you are going for a 2-way as stated above a 6.5"/1" combination
if by far the "best bang for buck" - a compact vented floorstander
of ~ 20L can produce satisfactory bass at a satisfactory level.

A 5.25" 2.5way is possible but generally the bass end is somewhat
more restricted in extension due to the driver parameters (being
more optimised for AV and the addition of a subwoofer). It is not
as cost effective due to having two bass / mid units.

If DST drivers are available at a reasonable price then its a no-brainer.

Though what drivers are actually available is not obvious at all ........

Worth some serious time checking out :

http://www.zaphaudio.com/
http://www.rjbaudio.com/projects.html
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://www.humblehomemadehifi.com/
http://htguide.com/forum/forumdisplay.php4?f=39

A good driver combo to look at :
http://www.geocities.com/woove99/Spkrbldg/ER18RNX_2Way.htm

If you want to roll your own a combo worth investigating IMO :
tweeter : Vifa D26NC55 , bass : Vifa MG18 (good midrange bias)

:)/sreten.
 
wiredmonkey

It's admirable that you want to build a speaker design from scratch and is the only way to learn. There's a saying that a person who has never made a mistake has never made anything... just have to learn from them.

For starters get the Loudspeaker Design Cookbook by Vance Dickason as it will give you a lot of information and references. I have a very, very basic design guide (around 2Mb download zip) that walks you through a budget speaker design and build plus some general info so you can get some ideas on what it takes.
http://www.darcheraudio.com.au/rzaudio/LDG.zip

Have a look around at the sites that have been given as they are valuable resources and read and read... then read again.

The 2 main things in design IMO is application and driver choice. Get that right and your on the correct path. Crossovers may just look like numbers and calculations but it's far from it and is the hardest part to get right. That normally only gives you a starting point and then it's tweaking and voicing by ear. Software will help a lot to get closer and Jeff Bagby has some excellent crossover spreadsheets at FRD.
http://www.pvconsultants.com/audio/frdgroup.htm

Someone around here once said to use the lowest order crossover to get the job done and that's always stuck with me... very wise words.

I might as well throw my 2 cents in and for a mid woofer, have a look the Peerless 830875 (Nomex) from WES as it's a great 6.5" driver. Just an awkward driver to rebate but doable. For a tweeter I prefer the SEAS 27TDFC but in the pic below used the Vifa (Peerless) DX26TG05-04 which is available from WES where the SEAS is not. Price can help make a choice for you if you have a WES account. I've used the SEAS/Peerless combo from undersize bookshelves to floorstanders and a great sound.

It's great living close to Andy as I can get to hear his creations and have another set of ears for mine. It's very important to get other opinions when voicing speakers but in the end they have to please your ears.

Good luck with your design and enjoy.
 

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wiredmonkey

On the question of comparison for a commercial speaker of similar or greater price, if the design is right there is no contest as there are no commercial restraints.... only budget considerations.

That little speaker in the above pic was built by a Tech teacher (I don't know him or ever met him) in Melbourne. He went around the Hi Fi stores and listened to speakers up to $2000 and found nothing that he liked nor surpassed what he had. A friend in Melbourne suggested these (he had built a floorstander version) and away he went. He is over the moon with the sound and said it killed anything he listened to up to $2000. He was amazed at what you can get for a modest amount (even better with a WES account) when doing a good DIY design.

The key to this design.... the driver choice and plenty of crossover tweaking plus it was designed for a particular application and not one size fits all.
 
diyAudio Member
Joined 2007
wiredmonkey;
To save you a few dollars you are free to borrow my copies of SDC, and I also have Weems and just this week a classic by Briggs.
Worth spending a week or two reading the basics, also check out the local library, there may be some literature there; if not join up and ask them to purchase particular titles you may be interested in, I've always found our local library very helpful.
There are quite a few speaker builders in this area but ony a few use this forum
 
"An unknown design, even for someone like myself, I think, will teach me much more and give me a much better understanding of considerations I need to take" I agree, (if you think the experts know what they're doing, check out the 'Enable' thread...;) )- just go for it...
 
PeteMcK said:
"An unknown design, even for someone like myself, I think, will teach me much more and give me a much better understanding of considerations I need to take" I agree, (if you think the experts know what they're doing, check out the 'Enable' thread...;) )- just go for it...


Hi,

The EnABL threads are fine example of your signature.
There are the "experts" and the self-appointed "experts".
An "unknown" design is fine. An "unknown" methodology futile.

:)/sreten.
 
This sure makes the sub box we built for my mates prelude at the age of 18 look like a pile of.. yer... ;)

Just waiting on approval for the WES account then I'll be ordering the seas tweeters and the p13 (if they have any left) ... unfortunately I'll be gone for a couple of weeks on a completely unplanned roadtrip of 4wd'ing, fishing and no idea what else - but when I get back I'll be sure to start posting pics. Thanks again for all the advice - I've been reading as much as I can from everything people have offered.

I agree a second set of ears is always helpful, though to be honest, mine aren't trained awfully well yet!

Moondog, thanks heaps for the offers of books :) I had to buy weems because, well, I had to buy some parts for work and that book was in their catalogue and yer, hard to say no! :D
 
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