mMar-Kel70 vs Mar-Kel70

[Bigun]

I now have a pair of new EL-70's on the shelf


I also have some Onken style boxes (a.k.a. derived from planet10 Fonken) which are very close to the mMar-Kel70 enclosures - mine are 6l with ports that are the same length but larger in area (I can reduce the area accordingly). Seems an easy path forward.

But I have enough of these boxes that I can combine them (with some surgery) to make a pair of larger boxes which have a volume just a couple of litres more than the bigger Mar-kel70.

Question: how would you contrast these two designs in terms of sound ?

[planet10]

Base volume of mMar-Kel is 4.7 litre, the Mar-Kel70 is 13 litre.

mMar-Kel sounds good but has a character in the mid-bass, upper bass that intimates, "i'm being held back by the small volume".

dave

[Bigun]

Dave,

Thanks for the rapid response !

Let me ask - do you think this character is related to the restricted volume ? - I'll have 6 litres on tap which gives me more room in this case if re-use the existing boxes.

OR do you think this character is related to the room around the driver ? - I'll have 15.1cm of width between side walls where the driver sits, the mMar-kel70 has 14.3cm. I combine some boxes to get a larger volume this wouldn't change ?

[planet10]

Sounds more like a volume issue. You get the feeling that the driver is being held back (and listening to the fullSize miniOnken, it is)

The millisize got to the width they are because of early reflections on the inside (took us 3 prototypes to get the shape right.

dave

[Bigun]

Good to know.

How important is recessing the driver into the front baffle - as there's already a hole cut out and the FE127 was not recessed it will be difficult to route a recess as the centre of the circle is in mid-air ?

[planet10]

With the fat bezel of the EL70, i'd say it is very important to get it flush, whether that be a rebate or building up around the driver.

dave

[Bigun]

I suspected as much - I can see now from the drawings for the mMar-kel70. Well that's going to be a bit of extra work to figure out. In the meantime I want to know whether these drivers make a sound

I did enough surgery to the driver magnet brace to allow me to install the drivers and connect the boxes up to my tube amp. The tuning is way off, I still need to reduce the area of the ports. And the tube amp is wired up for an 8Ohm load not a 4Ohm load. But it allows me to put some noise into the drivers.

I can already tell that a) there is waaay more bass than the FE127. b) the shrill of the 7kHz peak from the 127E is not present, c) the box tuning is off and d) the drivers need time to break-in.

The mounting screw holes don't line up with the old drivers. Fortunately the old holes don't go all the way through. If I like them the boxes will escape the bonfire and I'll probably take some time to refinish them - the veneer has not survived the test of time and needs to be removed. I'm tempted to spray paint the boxes.

Too early to say more.

[Rullknufs]

Originally Posted by planet10

With the fat bezel of the EL70, i'd say it is very important to get it flush, whether that be a rebate or building up around the driver.

dave

Do you think i should do that with my Mar-Kel70? Is it worth the job?

[planet10]

Yes, when you rebuild them proper

The 12mm chipboard probably wouldn't survive

dave

[Rullknufs]

Originally Posted by planet10

Yes, when you rebuild them proper

The 12mm chipboard probably wouldn't survive

dave

I'm not sure if i will rebuild them proper. Maybe if my dad has lots of spare time in his semester i may ask him if we should have a go at it.

I was more thinking about finding something that is 6mm thick and mount it on the outside of the baffle. And then sand it into a custom shape or something. Might end up quite cool if i do it like egg-shaped and a hole in it for the driver. What do you think? Wouldn't that be good for baffle diffraction stuff?