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Author Topic: Another CII modification..  (Read 31914 times)
Stefan I
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Posts: 141



« on: September 11, 2009, 08:49:58 PM »

Well, i have now listened enough to my CII,s to get an idea of what to do in first place, the worst is harsh sounding tweeters and some lack of definition in higher frequencys, the dip in the upper midrange is also noticed but it isn't the biggest problem.
My plan is to remove all innercables like i did in the C/V,s to put in Silspeak 440, they are quiet more opensounding than the original monster cable wich i experience suffer from some kind of nasality, in the same time i will change all bipolar capacitors to polypropylen except those on the bassdriver where it will be new bipolars, i also found new tweeters wich have almost exactly the same sensitivity as the original and the frequencycurve looks very good, hopefully i not need to adjust the level with some external resistors in the signalpath, i was so satisfied with the Seas tweeters i put in the C/V:s so i will go for Seas again, but this time i will try an aluminium dome, partly based om my listening experience where i want to add some more definition in the upper frequency and to compensate a little bit for the Silspeak 440 wich is also on the dark side with much body compared to the Monster, we'll see if it turns out the way i want.
A funny thing i recognised is that i haven't some tweeter adjustments on my CII:s like Vesa II has, furthermore i don't have bipolars at all for my tweeters wich is also different from Vesas.

Link to tweeters:

 http://www.seas.no/index.php?option=com_content&task=view&id=90&Itemid=114


 


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« Last Edit: September 12, 2009, 10:02:15 AM by Stefan I » Logged
vesaII
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Posts: 84


« Reply #1 on: September 12, 2009, 08:20:42 PM »

Hello Stefan

Have you checked impedance of your Seas? If it is same as original around 3000-3500Hz then your swap work ok electrically.

Funny how different your CO is.

This sure is one nice tweeter which measures and also looks like original Vifa d26tg-06 http://scan-speak.dk/datasheet/pdf/d2606-920000.pdf

/Vesa
« Last Edit: September 14, 2009, 07:38:55 PM by vesaII » Logged
Stefan I
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Posts: 141



« Reply #2 on: September 14, 2009, 09:43:47 PM »

One speaker is finished and listened to, i have made mono comparisons to the original one and that is not funny..
The modified behaves much more neutral and transparent and also separates instrument and actors in a much better way, the new Seas tweeter is also a lot different, it's now very easy to follow frequencyvariations in the top, the old Vifa was like mixing all frequencys in one, and sound very monotonous. Despite the new tweeter is good i will yet compare it to a Seas textildome wich i found had aproximately the same spec as the metal one, then i decide, but the Vifa it will never be again..

Crossover picture, Monster is only left for the rear tweeter, everything else is changed, even between the filtercomponents, to me those Monstercables sounds very coloured, VesaII i highly recommend you try some other stuff here.

Your Scanspeak is also very interesting!


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« Last Edit: September 14, 2009, 09:54:47 PM by Stefan I » Logged
Stefan I
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Posts: 141



« Reply #3 on: September 15, 2009, 11:18:12 PM »

Tweeter is now decided, my thoughts were right and the metaldome was the best here, the textildome was too soft on this speaker and together with my other modifications, i am satisfied and it's time to go further. Midrange is (like also Vesa said) a problem, it lacks resolution and some 3D soundstage is not to think about with this Vifa. This problem i think will be the most delicate and also the most difficult, finding a unit with good integration against both tweeter and bass, this can take some time.. Undecided
« Last Edit: September 15, 2009, 11:20:01 PM by Stefan I » Logged
vesaII
Getting there
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Posts: 84


« Reply #4 on: September 16, 2009, 06:04:09 PM »

Looks good, but it might take same time to burn in.

And yes mid is most difficult. You can change tweeter and have immediate improvement. But whe you put in new mid or woofer, then you need to alter CO and that is not easy one. Expecially with Snell: it really have strange values on parts...

My problem now with mid is too low efficiency and i also like to have more definition. This migh be next try: http://www.audax-speaker.de/index.php?module=shop_articles&index%5Bshop_articles%5D%5Baction%5D=details&index%5Bshop_articles%5D%5Bcategory%5D=4&index%5Bshop_articles%5D%5Bdata%5D%5Bshop_articles_id%5D=19&lang=en

Now link works. Sorry..

It has very similar frequency response as original Vifa, a bit less peaky only.

/V
« Last Edit: September 24, 2009, 04:42:40 PM by vesaII » Logged
Stefan I
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Posts: 141



« Reply #5 on: September 23, 2009, 06:41:17 PM »

Unfortunately your link doesn't work! Embarrassed  Those days i have put in some new midrange units, Seas again.                      

http://www.seas.no/index.php?option=com_content&task=view&id=102&Itemid=124

The sound reminding a bit of Vifa but without that dip around 1 Khz, it is quite more open up there..
After further listening  i am not 100% sure that the tweeters are the right ones, i will also try those Scanspeak wich seems to be an improved version of the original.  New Bassdrivers next, but i will play them like this for a while first.  I am also a bit curious of trying an active crossover, we'll see..



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« Last Edit: September 23, 2009, 11:08:10 PM by Stefan I » Logged
vesaII
Getting there
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Posts: 84


« Reply #6 on: September 24, 2009, 04:53:45 PM »

What is your problem with tweeter? Tweeter too loud? First aid could be L-pad. 3-5db

No Audax link works.

/V
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Stefan I
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Posts: 141



« Reply #7 on: September 24, 2009, 06:19:12 PM »

Since last i have tried with the frontgrills on, and then it was better, i was just thinking the same as you, to adjust level instead.
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Stefan I
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Posts: 141



« Reply #8 on: April 07, 2010, 10:23:45 PM »

This is how it looks like today, i have put the crossover outside the box and the bandpass is changed with new crossover points wich have resulted in a more natural upper bass and some more energy in the upper midrange, but this is just the first step, further modifications is now very easy to do, and i am afraid it will be some more before i am fully satisfied, and it will not be laying on an old carton in the end.. Roll Eyes



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Stefan I
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Posts: 141



« Reply #9 on: April 17, 2010, 05:00:46 PM »

12/18 12/18 with midrange working at 200-3000Hz sounded Ok at the beginning, but after a few listeninghours i experienced some shortcomings against original crossover, it appeared to be some distorsion around upper crossoverpoint wich caused unfocused soundstage, acoustic or electrical problem i don't know, i reconstructed the bandpass to a narrow band type and changed the order to 12/18 18/18 and 200-2700Hz, together with level adjustments on midrange and tweeter this looks like a better idea, i have not yet found some areas where i not prefer the new one, accept in the bottom end (wich is still left untouched and the same), so this is good enough so far. Now it's about to make one more with identical values as the other.. Tongue





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« Last Edit: April 17, 2010, 09:33:13 PM by Stefan I » Logged
Pure_Brew
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« Reply #10 on: May 01, 2010, 06:38:46 AM »

How do you know you are getting those slopes?
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Blog: Flux Junk
Stefan I
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Posts: 141



« Reply #11 on: May 01, 2010, 04:50:30 PM »

How do you know you are getting those slopes?

Yes, it is the electrical slopes, i haven't the equipment to measure the acoustic ones yet.
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Pure_Brew
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« Reply #12 on: May 01, 2010, 06:02:25 PM »

ok gotya. It's hard to even produce a solid electrical plan since the resistance dramatically changes with resistance.

I found that with change-and-listen experimentation, I get better results purposely gapping the crosspoint. Obviously this could/would create a bit of a drop-out at those frequencies, but it's much more pleasing to listen to on axis to me then having having big bumps there. Laying things back in the 2-3k region make the sound stage also sound like things are really coming from behind the speakers. Abonormal peaks in the 2-3k region make me feel like I'm being stabbed in the ears.
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Blog: Flux Junk
Stefan I
Full Member
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Posts: 141



« Reply #13 on: May 01, 2010, 06:47:52 PM »

ok gotya. It's hard to even produce a solid electrical plan since the resistance dramatically changes with resistance.

I found that with change-and-listen experimentation, I get better results purposely gapping the crosspoint. Obviously this could/would create a bit of a drop-out at those frequencies, but it's much more pleasing to listen to on axis to me then having having big bumps there. Laying things back in the 2-3k region make the sound stage also sound like things are really coming from behind the speakers. Abonormal peaks in the 2-3k region make me feel like I'm being stabbed in the ears.

Yes, many speakers have that dip around 2-3khz, and i have read something about that it is there for bringing some kind of stereo compensation for the human ear and how it works with frequencys and sound coming from different directions, a linear frequency is not always that wich sound most natural.
And yes, the electrical slopes is calculated with a fixed impedance, i was just going to add that in my last reply but you were faster.. Wink
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Stefan I
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Posts: 141



« Reply #14 on: June 18, 2010, 12:57:22 PM »

This project shows how important it is to listen during some period before drawing definite conclusions, lack of dynamics and onfocused soundstage was evident after a period of listening, it become boring to listen to music. To compare in mono in an initial stage under construction work wasn't so reliable after all, it told little on how the speakers behaved when played together, so back to electrical 12/18 on bandpass and further adjustments on co-points wich seemed to solve those problems (could be the phase), the Crossover construction is now actually much like the original but with different Crossoverpoints and component values to match the spec of the new speaker units. I also found the same Bassdrivers as in Vesas project at a good price, and need to rebuild the lowpass and maybe some work with the acoustics (cabinet) to make them produce a more linear fidelity.

Remember everything is made by ear so far...
« Last Edit: June 18, 2010, 02:40:48 PM by Stefan I » Logged
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