The Minimus 7 solution

[rongon]

Well, I put the drivers in the M7 cabinets with some poly batting and took a quick listen. The verdict? Well, they're OK. No bass, that's for sure. They are very efficient. They also go surprisingly high in frequency for a 4-incher. I think they have potential, but need to have some of the upper mid 'fierceness' damped down. They sound more 'intense' than I like (not relaxed enough).

I'm thinking the frame may need some damping. Tapping on it creates a ringing that can't be good. I should probably dampen the M7 cabinet too. I'm sure it rings some.

I used to use Roma Plastilina modeling clay on cabinet walls and speaker driver frames. Maybe there's something better, maybe easier to use. Any suggestions?

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[planet10]

Both A6m & FR88 will need new baffles. The A6 brings some cosmetic issues (bezel wider than box)

Measured the box at 1.7 litre.

dave

[IG81]

If working with one of the vented M7 version and using a subwoofer for the low-end, I'd just suggest to completely plug the vent to create a sealed box, or try to fill it with enough resistive material to go aperiodic (see that the BR double-hump disapears and yields a single peak on the system Z_curve).

As for being serious about converting an M7 enclosure for fullrange use, one could precisely cut a wood/bamboo baffle that will fit into the front recess of the grille-less enclosure. It would also be nice to adress possible ringing of the thin metal walls; ductseal or something similar might help, but will reduce Vb; possibly another reason to go aperiodic if that make the Q too high. I think a subwoofer will most often be needed, unless a fantastic driver is discovered!

IG

[rongon]

Has anyone experimented with damping the driver's metal frame? Or is any ringing from that of so little consequence that it can be ignored until ready for the very final tweaking?

I put an L-pad on the W4-930SF/M7, Rseries of 3 ohms, Rparallel of 7 ohms, in the neighborhood of -5dB attenuation. Wired them in parallel with my Tannoys, and using them as "reflective" speakers (firing up, reflecting off the back wall, sort of a sound diffusion effect). It sounds OK, more dynamic than the Tannoys alone.

I'll experiment with dampening them to make them sound more polite. They're a bit too raucous for me at this point. But the W4-930SF is a drop-in fit for the Minimus 7 cab.

[planet10]

Originally Posted by rongon

Has anyone experimented with damping the driver's metal frame?

Always. Ductseal.

dave

[rhapsodee]

Originally Posted by rongon

Has anyone experimented with damping the driver's metal frame? Or is any ringing from that of so little consequence that it can be ignored until ready for the very final tweaking?

I put an L-pad on the W4-930SF/M7, Rseries of 3 ohms, Rparallel of 7 ohms, in the neighborhood of -5dB attenuation. Wired them in parallel with my Tannoys, and using them as "reflective" speakers (firing up, reflecting off the back wall, sort of a sound diffusion effect). It sounds OK, more dynamic than the Tannoys alone.

I'll experiment with dampening them to make them sound more polite. They're a bit too raucous for me at this point. But the W4-930SF is a drop-in fit for the Minimus 7 cab.

You might want to look into a zobel network for the TB to tame the rising response, that could be making it sound harsh.

Alternatively, try eNABLE to control the cone breakup modes, that also contributes to harshness at multiples of cone breakup frequencies.

[rongon]

You might want to look into a zobel network for the TB to tame the rising response, that could be making it sound harsh.

Yup, tried that. It did help, just not enough.

try EnABL to control the cone breakup modes,

What is EnABL?


-=|=-

[rongon]

OK, eNABL (Planet 10) looks like it would be worth a try. I'll need to read up on that...

Also, there's a big spike in the response centered at about 7kHz. I think a compensation circuit needs to be put in for that. Of course, that will decrease the efficiency of this full-range, decreasing its usefulness. No wonder the driver is that inexpensive. No free lunch.

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[rhapsodee]

Originally Posted by rongon

OK, eNABL (Planet 10) looks like it would be worth a try. I'll need to read up on that...

Also, there's a big spike in the response centered at about 7kHz. I think a compensation circuit needs to be put in for that. Of course, that will decrease the efficiency of this full-range, decreasing its usefulness. No wonder the driver is that inexpensive. No free lunch.

--

I'm tempted to buy the same TB woofers for my Minimus 7. Do you have a graph of the response showing the 7k Hz peak? It looks very smooth on the graph published in Madisound / PE.

If you don't mind sharing details of the Zobel network that you are using?

Qualitatively, does the TB woofer full range sound better / worse than the original Minimus 7 woofer + tweeter with the original ragged response?

Thanks!

[portreathbeach]

You could try the Tang Band website... Tangband Speakers

They have all the info on their speakers on there.

I used there 3 inch full range speakers, but I need a sub to go with them now.