Tone Tubby alnico hemp drivers

Magnetar · « **Reply #180 on:** 10 Oct 2008, 08:24 pm »

Quote from: Rudolf on 10 Oct 2008, 08:17 pm

Erling,

I had to read through that thread twice, before I got it. You really shouldn´t blame M. for not answering your question. Certainly no ignorance involved. One never knows in which way the man at the other end of the line has been interrupted or distracted after seeing your posting. And the next time he comes back to the screen even more questions and comments have popped up. I´m sure Magnetar will be pleased to comment.

Rudolf

Actually I didn't want to insult him that's why I ignored the question. The answer is obvious. It has to do with several matters. I assumed someone asking that question would 1) not understand the answer or 2) argue with no true experience or facts - In either case I would appear to insult him - so I ignored it

Graham Maynard · « **Reply #181 on:** 11 Oct 2008, 06:36 am »

Hi Jeffac,

I take each individual driver wire back to the 'crossover' board, and then only a couple of feet of thick wire between that and the amplifier.

Even with foam diffusers in front of the B200 there was still a little 'edginess' (ferrite magnet?) to its output, and this could be smoothed by fitting a 35 to 100uH choke in series with it.

I use horizontal foam pieces when I have the protruding acoustic centre cone dustcap, but vertical fingers when running with an original dust cap, because the lower one partially covers the dustcap to better reduce *axial* beaming whilst still improving the horizontal radiation pattern;-

these being just clear of the surface of the cone at maximum output.

Cheers ....... Graham.

PS. I wonder if you have tried positioning wings or U pieces behind/ beside the woofers, or even besider the lower driver alone ? To me they ruin bass due to differential pressure generation modifying the woofer's otherwise open transduction capabilities.

scorpion · « **Reply #182 on:** 11 Oct 2008, 03:23 pm »

All settled with Magnetar.

/Erling

mcgsxr · « **Reply #183 on:** 11 Oct 2008, 04:21 pm »

Let's all play nice please, this is a great forum filled with generous people who want to share their experiences, and help each other learn.

That all said, there will be differing opinions, based on the subjective nature of our pursuits, and the objective approach some take.

I would appreciate it if we can continue to have a great atmosphere around here, and ensure that we are all being nice, even while disagreeing.

If you have an issue, please move to PM, or PM me.

Thanks, as you were!

painkiller · « **Reply #184 on:** 12 Oct 2008, 07:27 pm »

Over to something more positive...

It seems I've just bought a couple of Saba Greencone Alnico tweeters from Germany at a nice price. aa That could be interesting. Hope I'll receive them in a week or so. I'll be giving my impressions as soon as I have hooked them up. The holes in my baffles should fit perfectly. A little suspicious about their uneven response though. But at least they should be a better match than my dome tweeters, and they're dipole.

How long will I need to break in the drivers do you think?

jeffac · « **Reply #185 on:** 12 Oct 2008, 10:21 pm »

I'll take bets on a millisecond

and looking forward to hearing how they match with your big Tone Tubby's.

cheers.. jeffac

painkiller · « **Reply #186 on:** 18 Oct 2008, 02:43 pm »

Got the drivers yesterday. They were in mint condition, and I must say they look really nice. They seem like a perfect match for the Tone Tubbys. SPL appears to be spot on. I tried to cross them with a 4,7uF cap, but that seems too big, so I'll be playing around with different cap values this evening. So far it's a big

from me. I'll be looking forward to an intense listening session tonight.

Thanks for the tip jeffac! I believe you might have saved me a lot of money and grief.

jeffac · « **Reply #187 on:** 18 Oct 2008, 09:17 pm »

That was fast, must have paid express post

and nice to hear they match the TTs in SPL ... I thought they might. With the paralleled B200 and Saba mid, it sounds much better integrated second order passed which I could try because I had a spare 0.4 mH choke. Might be worth adding to the test list.

cheers.. jeffac

painkiller · « **Reply #188 on:** 20 Oct 2008, 06:58 am »

Thanks for the choke tip. I had som 470uH ones around. It works way better than just a cap. I guess around 3,9uF would be the perfect cap value. Have to play around a bit more before I'm done. Now it sounds really well integrated. Don't need the rolled up towels any more, and there's no beaming.

The saba tweeter is actually very good. Playing sine sweeps the response doesn't fluctuate much between 5000 and 15000 Hz. But beyond 15kHz it drops off rapidly. So I'm thinking in the lines of a nice efficient ribbon tweeter with extension up to 40kHz.

jeffac · « **Reply #189 on:** 20 Oct 2008, 11:45 am »

Hi painkiller,

Those Saba's look like new and glad to hear that they're working better with the second order filter.

Wires connected in anti-parallel?

I've been meaning to try a cap around 4 uF too, just happened to have some big 4.7 uF oil Obbligatos spare but will try that value soon.

Nice you could measure some the 'real world' frequency response of the Saba tweeter and the fact that it dies post 15 kHz is very interesting as I just happen to have some Aurum Cantus G2Si ribbons. I'd originally thought of firing these backwards with the B200 to help with spacial information and 3D imaging. However, as the Saba is now providing a lot of HF rearwards for this, with a small value cap, these ribbons might be worth a shot firing forwards. More homework on how best to go about this but thanks for the idea.

Keen to hear what cap value you settle on and more on sonic impressions then.

cheers.. jeffac

painkiller · « **Reply #190 on:** 23 Oct 2008, 06:01 am »

Well, I've been switching a lot back and forth lately. Switching cap values, polarity, inductor, T-bass and so on. I've landed on 4,3uF 1st order, and added a couple of neodymium magnets to the Saba tweeter for increased output. The SuperBoy rolls off very slowly and actually has useful output up to 10kHz.

So first order filter was the only sane option.

I'm still not quite sure about the Saba tweeter. It seems to have a steadily rising response from 8kHz and up to 16kHz, which gives a broad dip in the frequency range. And theres absolutely no output at 17kHz.

I wish I had some measurements to back it up, but my measuring mic is not working properly. I've been playing with the tone generator in CoolEdit though, and I have perfect hearing to beyond 20kHz.

painkiller · « **Reply #191 on:** 25 Oct 2008, 12:41 pm »

Jeez, these drivers are really giving me a headache.

They are too freakin' loud. I've finally managed to get some kind of normal frequency response without EQ, but far from the way I had imagined in the beginning.

I now have both 15" drivers coupled to the T-bass circuit to get useful bass response. The Alpha 15A are definitely not as efficient as stated in their datasheet and need a lot of help. To dampen the midrange even more I had to add a 10R series resistor. This brings the midrange down to the level of the Saba tweeter and Eminence bass.

This would have been sooo much easier with the 10" driver at 94dB SPL, instead of 99dB.

painkiller · « **Reply #192 on:** 17 Nov 2008, 01:49 pm »

15" Superboy sans dust cap:

DIY Superboy/Saba coaxial driver, with Maynard's (mandatory) foam finger tweak:

Polarbear · « **Reply #193 on:** 17 Nov 2008, 05:34 pm »

Kool

How does it sound?

Cheers
Bjørn

painkiller · « **Reply #194 on:** 18 Nov 2008, 07:14 am »

Well, it's definitely a very revealing combination. Good recordings sound absolutely wonderful, and poor recordings sound really awful. Dynamics and transient response is up there with the big horn systems. Very good imaging and of course that mesmerizing ambient OB feel. Very lifelike presentation, especially at loud levels. There's only output up to 17kHz, so it sounds a bit muffled to me and my perfectly healthy ears though.

The tweeter and 15" integrate seamlessly with a 1st order high pass at around 10kHz. It's quite frightening how good such a simple system sounds. I guess any sane audio engineer would chop my head off for this. 15" driver playing at 10kHz.

jeffac · « **Reply #195 on:** 18 Nov 2008, 07:31 am »

Hi Painkiller,

Nice work, bit scary cutting out dust caps I imagine, which I found with doing the same with my B200s. Have you had to cover the back of the Saba tweeter with anything, felt for example, to block energy from the TT impacting on the back of its cone? Just wondering whether this might be an issue contributing to the 'muffled" comment. Up there for creativity though and sounds like they're sounding really nice.

cheers .. jeffac

painkiller · « **Reply #196 on:** 18 Nov 2008, 08:08 am »

It was totally on impulse, so I didn't have the time to get scared.

Just took a kitchen knife and cut out the dustcaps in two minutes. It was surprisingly easy. I just had to see what they looked like inside.

I didn't cover the back of the sabas with anything, although I probably should have. Might be a tweak worth trying out. The frequency response seems fairly straight, but there could be some distortion I don't know of.

jeffac · « **Reply #197 on:** 19 Nov 2008, 11:33 am »

Being attached to the voice coil former and trying to be neat to fit phase plugs, the B200 dustcapectomy required the nerve racking scalpel treatment, and a quite Sunday morning free of distractions.

A question regarding the quite linear FR you've now got and the fact that I followed your lead and went with a 10 mH low DSR choke for GM's T-bass circuit for my paralleled Alpha 15As. What series resistor and cap values have you settled on? I'm currently using 0.47 ohm with 880 uf in caps, low bass is boosted nicely but there seems to be a bit of a hole in the upper bass. Just wondering whether you might be using something a bit lower in cap value. Mind it could simply be phase nulls due to overlapping with the B200 and Saba mid as the Alphas are low passed quite high, at ~1k using a 0.56 mH choke.

cheers.. jeffac

painkiller · « **Reply #198 on:** 19 Nov 2008, 04:49 pm »

I landed somewhat randomly on 0,5R and 580uF. I use 6,8mH P-core for the T-bass and an unknown value for low pass.

It's passed quite high, but nowhere near 1kHz. No hole in the upper bass response, just a general sensitivity mismatch, so I still need EQ below 200Hz. I hope that an additional 18" driver will aid this. I might want to replace the Alpha 15A with a lower Q driver also, to get a bit dryer bass. I'm not very impressed with the Alphas.

ttan98 · « **Reply #199 on:** 19 Nov 2008, 08:40 pm »

Quote from: painkiller on 19 Nov 2008, 04:49 pm

I landed somewhat randomly on 0,5R and 580uF. I use 6,8mH P-core for the T-bass and an unknown value for low pass. It's passed quite high, but nowhere near 1kHz. No hole in the upper bass response, just a general sensitivity mismatch, so I still need EQ below 200Hz. I hope that an additional 18" driver will aid this. I might want to replace the Alpha 15A with a lower Q driver also, to get a bit dryer bass. I'm not very impressed with the Alphas.

Probably why Hawthorn's Augie has Qts less than 1, in fact Qts=0.9.