Where do i get plans for m8a?

[jerusalem]

I have desided to build new 2 way speaker and after some searching
M8a seems to be the one.I actually made before one diy speaker,
but it was a disappointment, too cheap parts i think...

Why ;x( m8? seems to fulfill many reasons: smooth ,airy and dynamical sound for modest prise.
From all the versions of m8a i think Mkiv might be the best one,
because it has to be bookshelf for a small student apartment.

So i have to ask someone to send here, or mail me the plans for
m8a mkiv.Help most appresiated etcetera... and yes english is not my
original language so patience with my incomprehencible droodles.


jarkko.kinnunen0@saunalahti.fi

[ThomasW]

This link will get you started.

Link not available

Here's a link to Andrew's website where he talks about the pair he built then upgraded

https://web.archive.org/web/20050920114555/http://www.mts.net/~glendap/DIY.htm

Here are some threads about them

https://www.htguide.com/forum/showthread.php?t=3299&highlight=slow+work+takes+ti me

https://www.htguide.com/forum/showthread.php?t=3284

[JonMarsh]

BTW, you could drop in an RS28A tweeter in place of the Vifa XT25, if it's available where you live, and this would be an upgrade comparable to the modified MkIV with SS98000 tweeter.

Regards,

Jon

[Jonasz]

Well, to my knowledge the RS28 aren't available here in Scandinavia but even if you import them from the US they're a LOT cheaper than the SS9800 and 1,5 the price of XT25. Go for the RS28! :P

Jonas

[jerusalem]

Well if RS28 is as smooth/smoother than vifa, why not?
Do i need to make any changes to MKIV crossover?

[DearS]

Well if RS28 is as smooth/smoother than vifa, why not?
Do i need to make any changes to MKIV crossover?

hearing how jon is designing an M8a dipole with the RS28 tweeter, this is a question that interest me also. for the MT to dipole upgrade.

[jerusalem]

I have made some plans about box for speakers, and i think this (refer picture) would be fun to make and look at.

Backside would be little less tilted than frontside,so If i calculated that it maintains its inner size same as "normal" boxshape, would this kind of desing
be acoustically bad?

[Jonasz]

I strongly believe you should keep the baffle straight. The M8 is designed this way and I'm pretty shure things would go wrong if you tilted the baffle. Regarding the RS28 I think just minor changes would be needed if any, I'm sure Jon or Thomas will fill you in on that!

Jonas

[FrancoB]

Jonasz,

You can buy them from http://www.boxen-baustelle.de in Germany.

Cheers,

Franco

[ThomasW]

would this kind of desing be acoustically bad?

The crossover is optimized for a straight front baffle. If you use an angled front you need to redesign the crossover.

[JonMarsh]

Thomas has got that one right...

The crossover phase relationships through the crossover region were carefully tuned so that with a flat panel there's a very wide vertical window in the crossover region, one which extends upwards even higher than typical- the first evident notch in anti-phase behavior is when you go below the woofer/tweeter axis, towards the floor, which can be rationlized that it helps reduce floor bounce effects . There's a strong null notch on axis if the drivers are wired backwards from the correct phase. They're optimized for both sitting and standing listening, as that is my preference (I stand while working in the kitchen or other places, so it's important to me that the response be quite flat even on a 15-25 degree upwards axis for stand mounted speakers).

The Vifa XT and RS28A have very similar impedance curves (the Vifa uses copper in the VC gap to control inductive rise also), absolute impedance, and FR from 700 Hz up to 12 kHz. But the RS28a has more radiating area, and better linear distortion and nonlinear distortio behavior, especially the latter below 3 kHz.

You could just drop it in, but a better approach would be to use the zobel networks as developed for the RS28a version of the Modula crossover (posted on this forum), substituting the different Q LCR and RC networks.

Regards,

Jon

[Lex]

Where does the flux capacitor fit into this equation Jon?



Doug

[ThomasW]

Where does the flux capacitor fit into this equation Jon?

Do to the ever increasing pressure to lower costs, environmental concerns, as well as significant cuts in our government funding, ultra-exotic components are only used in our high-end 3-way systems...... :wink:

[TacoD]

Where does the flux capacitor fit into this equation Jon?



Doug

Hmm, good question, do not reverse the polarity .

[JonMarsh]

Due to the new European standards, both ROHS and WEE (the latter requiring provision for planned life cycle take back from the consumer and disposal) we will NOT be exporting Flux capacitors from AudioWorx to the European Union any longer.

Sorry guys.... it's just too much beauracracy and red tape. That, plus we haven't been able to figure out a way to make them without using Cardas Quad Eutectic solder, and that's now a Romper Room No-No in Europe (due to lead content in the solder). :naughty:

Sorry guys....

[Jonasz]

FrancoB: Thanks, I've missed that shop. I'm happy to say that the pricedifferences compared to US is not ridicilous (as they usually are :evil: ) by any means! :P

Jonas

[Lex]

Way to run with the flux capacitor thing.

so, what do they solder over there with now Jon, 2 sticks to make fire and a stick of bubble yum for adhesion?

[JonMarsh]

Well, it seems that bad if you're used to good quad eutectic solder...

The SMD assembly processes now have to do 260C instead of 230C. Not nice to your components, you know.

Now, I guess they use various tin/silver/copper or tin/silver formulations. Stuff's a bit weird, glad I don't have to work with that myself. Then, there's the whole tin whiskers thing, a few different approaches to dealing with that, but the really effective ones involve more expensive plating processes.

Glad I have several pounds of the Cardas on hand... :B

[Marzen]

Well, it seems that bad if you're used to good quad eutectic solder...

The SMD assembly processes now have to do 260C instead of 230C. Not nice to your components, you know.

Could be worse...try juggling new Pb free ramps on a 4 zone oven with 0.603 parts AND 1st time BGA use AND new CE/TUV req's for ESD safety?!?
:E Talk about your horse pills!

[JonMarsh]

Yeah, I feel for you... this whole ROHS thing certainly has the industry in a dither... and it's far from wrapped up and done. Many of the countries are still issuing/modifying/updating their interpretation of the regs- and it's starting ot happen over here, but every state is taking a different approach to that and to electronics waste disposal. It's a regulatory compliance nightmare.

[FrancoB]

Jonasz,

You're welcome. I ordered a pair of RS28 from him. He's a pleasure to deal with. And you're right, the price difference is not that big.

I'm in the process of building a twoway with the C95 from Accuton. I replaced my MB Quart MCD25 with the RS28. No comparison.

Thanks to MarkK and Jon for letting us in on this gem.