Bottleneck's crossover experiment

bottleneck

bottleneck

talks a load of rubbish
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yeah, thanks to Rob, he was helping me with crossovers.

unbelievable really - we just stuffed a simple first order on the bass, 1st order bandpass on the mid, 2nd order high pass on the tweet, and bang, measured it +-5db in room measured response all the way from about 30hz to 18khz.

Im happy now, I can flog a couple of amps and my active crossover.

It's an interesting difference (between active and passive in my system) - but I'm sticking with passive, prefereing the quietness, lack of hiss, neutrality over the very enjoyable bass wallop you get with active bass.

Maybe one day I'll build an active bass crossover and go passive on the mid and tweet. I think that would be a great compromise.

Still, happy for now.

PS
Have I just thread-derailed a thread about thread derailment?

oh, the irony.
 
http://www.hificollective.co.uk/kits/glasshousehome.html

300bsep_side_tjc.gif
 
The speakers are working well given we had an afternoon to get the crossover up and running. Just needs a slightly higher value inductor on the bass section (and higher spec - lower dcr) and it should be settled.

The SPL capability of those drivers is truly frightening - you certainly wouldn't want to accidentally put full volume in from the pre!

Once the network is built and boxed (its hanging off the back of the speaker at the moment) it might be work experimenting with different slopes and orders.
 
yes, its a lot of fun!

with such a simple crossover, Im going to splash out on the inductors and get some really great ones.

kind of thinking of either of these -

1)
Air core foils -
.55 dc resistance, £26.
very, very low vibration (therefore distortion) - about the best there is.
but slightly higher dc resistance. only .55 though..
http://www.hificollective.co.uk/components/mundorf_foilcoils.html



or

feron-core inductors
£20.38, very low dc resistance (0.09), but vibrates more and therefore this is translated to distortion more - see graph in link number one above.

http://www.hificollective.co.uk/components/mundorf_feroncore.html

That really is the only thing that I will probably change. It is '' there or thereabouts'' within a whisker I think at the first attempt.

will try and get some pictures up.


Nando...
I put a link above the picture of the amp.

Sadly, I believe the last of these kits has now been sold. There may be 1 left, but I dont think so.. (for anyone reading).

Its roughly £800 plus shipping plus valves (plus build cost if you dont do it yourself).

great amp, with audionote transformers in it.
 
Hi Chris,

I'd still go with the feron-core for two reasons:

Half an ohm reduction in dc resistance is well worth having, certainly if you drive from a SS amp, though less so if using tubes.

The vibration theory is just that - I cant see any context whatsoever for that graph on the site. How was the test conducted at Mudorf?
I'm sure you can induce vibration effects into an inductor if you strap it to a jack-hammer, but we need to see the effect under real-world conditions.
In the case of this speaker, the crossover is housed externally so the point re vibration really can be ignored IMO.

Lastly, you can saturate ferrite cores and yes distortion will rise, but in this speaker system with the huge sensitivity, that isn't an issue.
 
just used the drive units figures from the internet, and punched it all into various internet crossover programs.

horns sound good on 1st and second order crossovers (its been my experience on listening to date, especially simple 1st order), so it is quite rudimentary really.
 
just make certain you don't saturate the ferro cores .....or make certain there big enough to cope with signal your going to stuff through the inductors ...

for myself I preffer air cores after comparing the two side by side several years ago ...

the air cores allowed the music room to breath if that make any sense...
 
Hi Zanash

Good to see you again.

Did you try Ferrite cores on the bass?

Most people I speak to prefer some kind of ferrite inductor on bass cones, due to the low dc resistance.
 
mescalito - what amplifier do you use?

how about a picture?

I personally think the copper top of the 300b valve amp looks lovely. Certainly nicer in the flesh (IMHO) than my audio synthesis desire or EL84 amp

amp6.JPG
 
bottleneck said:
Hi Zanash

Good to see you again.

Did you try Ferrite cores on the bass?

Most people I speak to prefer some kind of ferrite inductor on bass cones, due to the low dc resistance.
Click to expand...

Air core on the bass if ok if the inductor is of truly gargantuan proportions, otherwise resistance is too high and you kill electrical damping. The effects could certainly be perceived as allowing the sound to breathe, but its doing that by removing the electrical brake on the bass driver. You get bigger, more expansive bass at the expense of accuracy, particularly transient accuracy and and ability to clearly hear into a complex bass mix.

Don'r worry about saturation. The system is hovering around 100dbw sensitivity on the end of a 9w valve amp - it aint gonna saturate! :)
 

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