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Post by MartinT on Jul 12, 2015 21:10:10 GMT
Pretty much - 10 ohms should be around room temperature. Yes, NTC means resistance reduces as temperature increases.
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Post by speedysteve on Jul 13, 2015 23:00:28 GMT
Cool:) Pun intended. Will give it a try.
Can always add a few ohms to get the start res to what I want...
Sometime I will get my infra red temp gun out and see what happens to the Inuke with and without air flow as I use it.
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Post by MartinT on Jul 14, 2015 3:48:37 GMT
Run a hair dryer over the thermistor and watch the fan speed.
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Post by speedysteve on Jul 20, 2015 21:32:54 GMT
Been thinking about thermistors some more and reading a bit more about INukes from those who drive em hard - reckon its difficult to know where to put the thermistor as you want it sited exactly on the component that is going to get hot first and its always reactive / likely to be late in on the action... If there was a great sink it would be easy, but then fan cooling would not be needed  Too big a resistance and the fan won't start soon enough as it needs a fair bit more current to start it than run it fast enough to have reasonable air flow. Therefore I'm sticking with my current solution of enough fan speed for constant cooling air flow wherever it may be needed, but not enough to disrupt my listening with fan noise;)
Could just put it in as the resistor as have currently and near where I think may get hot and then if it does the fan would ramp up faster... |
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Post by John on Jul 21, 2015 4:27:33 GMT
I think what you doing is Okay as the amp is not really being pushed
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Post by MartinT on Jul 21, 2015 6:28:06 GMT
It might take a few trials but you could run a resistor in parallel with the thermistor to just get it going, or one in series if the idle fan speed is already too fast.
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Post by speedysteve on Jul 27, 2015 20:12:08 GMT
Right now I'm trying out a pair of 400Hz tractrix horns on the Vitavox S2's. Sound bit different to the 550's...  |
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Post by speedysteve on Jul 28, 2015 20:37:14 GMT
Next up will be a pair of Le Cleac'h profile horns on the S2's... Will be interesting to put that one to bed!
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Post by speedysteve on Sept 14, 2015 18:56:27 GMT
I tried a pair of Le Cleac'h horns on the upper mid Vitavox S2 channel.
They are similar in cutoff frequency to my smaller tractrix.
TBH they did not do any better than my tractrix horns in real world listening.
I prefer the larger 400Hz tractrix.
I've learned that lower freq horns sound better on the S2s. Probably due to the fact that their throat and progression angle more closely resembles the internal angle of the S2. Equals better wave front progression from driver to horn I guess..
400Hz Le Cleac'h would be to big to use in my system. Multi way Le Cleac'h are not a practical proposition simply due their physical size.
Unless you have massively high ceilings and can sit a long way from them - to get cohesiveness.
I had a fellow hifi enthusiast here for a listen.
He was taken aback by the integration achieved by the system... Wouldn't want to upset any of that.
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Post by John on Sept 14, 2015 19:02:35 GMT
Yes your system attacks and certainly blends well together A kind of musical event
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Post by MartinT on Sept 14, 2015 21:55:09 GMT
Agreed, Steve, it was only when we were listening to a single horn at a time that we could clearly hear what each one was doing. As a system, they integrate fantastically well and are very cohesive. Are you happy with the Behringer on bass duties?
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Post by speedysteve on Sept 15, 2015 19:41:50 GMT
Yes. It is just great.
I have a 12" mid bass driver itch that I need to scratch sometimes too!
A bit of Hornresp modelling shows that if I extend the throat of my existing exponential horns a few birch ply rings they would work very nicely with the smaller drivers. That's pretty much where they started out...
I am not really dissatisfied at all with what I have. The JBL2220s are fantastic. Just like to tinker...
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Post by speedysteve on Oct 1, 2015 20:49:21 GMT
A little update: I'm a firm fan of the 400Hz Tractrix horn on the Upper mid Vitavox S2 channel... Also I've been thinking for a while now to try a 12" Eminence Kappa in the Mid bass horns. I do enjoy the sound of my wide throat short exponential with the excellent JBL 2220's but I have to try 12" and now is the time... So I will extend the existing horn. A bit of Hornresp shows that the ideal for the Kappa 12 would be  Then I modeled the adapter piece I will make to fit the existing horn and lengthen it to the 110cm mark. I will use segments of 21mm birch ply - same as rest of horns and thanks to Hornresp export I get the cutting guide:)  The Kappa's are on order and the rings will be cut and glued tomorrow! This is how the modded horn will look schematic wise and the modeled acoustic power Looking forward to trying 12" mid bass... |
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Post by MartinT on Oct 2, 2015 6:50:15 GMT
What are you expecting to hear, Steve? Will you lower the crossover point to the tapped horns?
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Post by speedysteve on Oct 2, 2015 8:39:48 GMT
Expecting faster and more tuneful in the upper region esp.
Admittedly the upper region here is low crossing as I do at 300Hz to the mid horn.
300Hz perhaps isn't a lot of work for a good 15" driver either but hey ho it's fun trying.
I'll keep the same lower crossover point at around 90. The tapped horns will go up to 100 no problem.
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Post by speedysteve on Oct 19, 2015 10:12:20 GMT
Well, our pending move had delayed any thoughts of modding the mid bass horns. It looks like I am taking the kit as is - no real problem as I do blow a bit hot and cold as to whether to even bother trying a 12" in the mid bass - but at some time I probably will. Thoughts instead turn to the tapped horns as deeper squatter ones may work better in the new room. I have quite a few options. Try the ones I have in several different positions, sell them and build an pair specifically for the room. Squatter ones model the same but there will be more folds so they could sound a bit different. I could also modify the ones I have sot he exit is in a different place or to be half height / twice the depth - that might also work well. More on this later. In the meantime I have a 400Hz tractrix plug/mould to think about making as that is the priority |
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Post by John on Oct 19, 2015 10:26:18 GMT
Thank s for the update Steve
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Post by MartinT on Oct 19, 2015 16:42:30 GMT
Hope to hear it when it's all setup in the new room, Steve.
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Post by speedysteve on Nov 10, 2015 21:29:46 GMT
Well still not moved yet but very nearly!...
Today I modded the upper mid and tweeter stand arrangements so that the upper mid horns with Vitavox S2's and the Raal Lazy ribbon tweeters are in line with the mid bass mouths (if that makes sense?).
This is because the current arrangement of mounting and stands won't work in the new space. The black metal frame stands will dissapear and the mid horns (highest up) will be in a different position! More on that once we've moved;)
So they are playing into open air not set back in with the mid and mass bass mouths ahead of them.
It's something I've toyed with before and did a half way test a while back.
I had a quick listen (ok but needed time aligning)... It just does not hang together as well until time aligned.
This evening I time aligned all channels so they are all locked on time zero, first peak positive, in relationship to one another.
This is a pleasant operation using Holmimpulse and measuring mic and to adjusting the delays in Najda (DSP X/O Dac etc).
The signal sweeps do drive Marie mad though:)!
The tapped horn subs are of course set at 0.
The rest is about 22ms delayed as the tapped horns are 4.2m long and set behind the rest physically.
Moving the mids and tweeters forward meant an increased delay on those channels to compensate. BTW as Najda is only a 4 way solution (I've not purchased the 5th way expansion board yet!), the tweeters are still physically aligned to the upper mids... One day I will get that expansion board!
Bringing the upper channels into clear air certainly has its benefits. The S2's truly shine. They are great drivers!
I'm hearing some new dynamics and range that was rather sheltered before, subtle but def there to be heard. Of course I knew this, but it's getting around to doing it and when things sound good sometimes you wonder if it is worth it - well this was!
M
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Post by John on Nov 11, 2015 5:02:13 GMT
Yes can always be a bit of surprise what is there
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