crd97086 Posted May 8, 2011 Share Posted May 8, 2011 Hello. Last weekend I posted pictures and initial impressions about the new Vittoras I had just received from Volti Audio. I thought you might like a look at the marvelous crossovers that Volti Audio uses and the incredible versatility they give you with these types of horn loudspeaker systems. I wish all manufacturers would give you this ability to tailor the sound more to your own personal taste, with engineering standards of course. For the midbass there are 3 settings. Below is the setting for the most midbass. Link to comment Share on other sites More sharing options...
crd97086 Posted May 8, 2011 Author Share Posted May 8, 2011 This setting is for the 'medium' midbass setting. Link to comment Share on other sites More sharing options...
crd97086 Posted May 8, 2011 Author Share Posted May 8, 2011 And this setting is for the least midbass. Link to comment Share on other sites More sharing options...
crd97086 Posted May 8, 2011 Author Share Posted May 8, 2011 On the higher frequency board, the midrange has 28 gradations that go from 0 dB down to -21dB. This is simply wonderful. I immediately discovered that fully open was way too much. I then tried Volti Audio's suggestion and lowered it to the setting for -9 dB. That drastically improved the depth and overall quality of the soundstage. Today I tried the lowest setting, -21 dB, but that was just plain too much. Below is a photo of the high frequency driver so you can picture how easy this is to do. Link to comment Share on other sites More sharing options...
crd97086 Posted May 8, 2011 Author Share Posted May 8, 2011 The tweeter can be run as set by Volti Audio, or you are able to raise the tweeter output by 3dB with the simple removal of 2 resistors from the underside of the high frequency board. Link to comment Share on other sites More sharing options...
crd97086 Posted May 8, 2011 Author Share Posted May 8, 2011 I have the tweeter running at the higher setting. I thought some might be interested hearing about what is out there. Below is one last photo of the entire crossover which came with my Vittoras, they are the 'split' style. Link to comment Share on other sites More sharing options...
Guest " " Posted May 8, 2011 Share Posted May 8, 2011 I like the brass screws...... Link to comment Share on other sites More sharing options...
muel Posted May 9, 2011 Share Posted May 9, 2011 I like the brass screws...... hmm... I predict comments from JB that will have something to do with brass monkeys. Thanks for the pictures! If you haven't seen the pictures and youtube video of the Volti Audio shop you are in for a treat! Link to comment Share on other sites More sharing options...
DizRotus Posted May 9, 2011 Share Posted May 9, 2011 Here's a link to the YouTube video. It's worth your time to view it. Greg's shop is extremely impressive. http://www.youtube.com/watch?v=hcyA0K2Df3I Link to comment Share on other sites More sharing options...
Guest " " Posted May 9, 2011 Share Posted May 9, 2011 hmm... I predict comments from JB that will have something to do with brass monkeys. We try to be careful when we respond to threads that refer to Gregs work. Greg is an artist and questions about technical issues like "when adjusting the tap choices...how is the relationship between impedance and capacitance managed? Moving to 4X from 2X would half the required capacitance value in order to maintain the correct crossover frequency and we only see one capacitor?, moving to 8x from 4X would halve it again" are often the start of misunderstandings, in as much asking a stone figure artist if he knows what type of blades where used to mine the rock being used in the art work. Often the folks that start these threads, can't answer these technical questions either. Link to comment Share on other sites More sharing options...
Blvdre Posted May 9, 2011 Share Posted May 9, 2011 SF, is that swamping resistor I see? Maybe gleaned from ALK's constant impedance design? Link to comment Share on other sites More sharing options...
Guest " " Posted May 9, 2011 Share Posted May 9, 2011 SF, is that swamping resistor I see? Maybe gleaned from ALK's constant impedance design? Even with a 10 ohm swamping resistor, you still need capacitor tweaks otherwise the crossover frequency shifts. if you assume tap 3 is targeted for 8.4 ohms at 400hz, moving to tap 4 results in 7.3 ohms and 485hz and moving to tape 2 results in 9.2 ohms and 390hz. Tap 3 picked to minimize the shift effect. Link to comment Share on other sites More sharing options...
mark1101 Posted May 9, 2011 Share Posted May 9, 2011 Stacking inductors like that can cause interference. Link to comment Share on other sites More sharing options...
crd97086 Posted May 9, 2011 Author Share Posted May 9, 2011 Have you heard it? Link to comment Share on other sites More sharing options...
greg928gts Posted May 9, 2011 Share Posted May 9, 2011 SF, is that swamping resistor I see? Maybe gleaned from ALK's constant impedance design? Yes, I got the idea for using a swamping resistor on the autotransformer from ALK. Of course you do know that ALK got the idea from someone else, don't you? It's all good. This is how things are designed and built. ALK has made his crossover designs available to the public for years. Eventually it becomes common knowledge. I appreciate ALK's efforts and thank him for his contributions to the crossover designs of our speakers. I personally have benefitted from his designs for many years. Greg Link to comment Share on other sites More sharing options...
Guest " " Posted May 9, 2011 Share Posted May 9, 2011 Greg in pursuit of constent impedeance, a shifting crossover frequency is introduced, while never really achiving the constent impedeance claimed. Even with a 10 ohm swamping resistor, you still need capacitor tweaks otherwise the crossover frequency shifts. if you assume tap 3 is targeted for 8.4 ohms at 400hz, moving to tap 4 results in 7.3 ohms and 485hz and moving to tape 2 results in 9.2 ohms and 390hz. Tap 3 picked to minimize the shift effect. A better approach would be to add the correct capacitor for each tap setting inbetween the autoformer and the driver, right off the tap. This will eleminate frequency shitfs. You still a the large cap before the autoformer, which is there to prevent the autoformer from shorting out. The autoformers inductance is so low, that with out the cap, you would loose even more LF. Link to comment Share on other sites More sharing options...
greg928gts Posted May 9, 2011 Share Posted May 9, 2011 Greg in pursuit of constent impedeance, a shifting crossover frequency is introduced, while never really achiving the constent impedeance claimed. Even with a 10 ohm swamping resistor, you still need capacitor tweaks otherwise the crossover frequency shifts. if you assume tap 3 is targeted for 8.4 ohms at 400hz, moving to tap 4 results in 7.3 ohms and 485hz and moving to tape 2 results in 9.2 ohms and 390hz. Tap 3 picked to minimize the shift effect. A better approach would be to add the correct capacitor for each tap setting inbetween the autoformer and the driver, right off the tap. This will eleminate frequency shitfs. You still a the large cap before the autoformer, which is there to prevent the autoformer from shorting out. The autoformers inductance is so low, that with out the cap, you would loose even more LF. If what you are saying is correct, it must be the case with the ALK Universal network as well. Greg Link to comment Share on other sites More sharing options...
Guest " " Posted May 9, 2011 Share Posted May 9, 2011 If what you are saying is correct, it must be the case with the ALK Universal network as well. it is the case....but in Al's case he uses an additional transformer to level adjust the high end. The transformer presents a constant impedance to the amp and as you select the varying db reduction settings, no crossover frequency shifts occurs nor the below indicated impedance variations. To explain the concept of transformers better. In the attached is a schematic of an audio output transformer. A1 and A2 is after the capacitor. The impedance will always be 8 ohms reguardless of the tap setting selected across E1 thru E7. E7 provides a 1.5db reduction. E6 provides a cumulative 3db level reduction (2X). E5 thru E1 follow the standard 4X, 8X, 16X, 32X or -6db, -9db, -12db, -15db. No swamping resistor needed. No frequency shifts. Impedance is constant. This particular transformer is superior to the T2A type transformers. This one has an inductance of 170mh, whereas the T2A type's have an inductance of 30mh. power handling is 300 watts vs the 15 to 25 watt T2A types. Link to comment Share on other sites More sharing options...
greg928gts Posted May 9, 2011 Share Posted May 9, 2011 SF, you're just trying to cause trouble here. Please stop. Al does not use "an additional transformer to level adjust the high end" on the Universal networks as you say. I built ALK Universal networks under license for Al. The wiring and parts I use in my VT networks for the autotransformer on the midrange are exactly the same. ' What is your point in bringing this up? The OP didn't ask for this, he just wanted to say to the group that he's really happy with his very versatile crossovers. Let's top hijacking his thread. If you want to try and discredit Volti Audio, start another thread, and I will thank you for the attention you draw to my company. Greg Link to comment Share on other sites More sharing options...
Guest " " Posted May 9, 2011 Share Posted May 9, 2011 Greg You brought up Al's products....heres the subject transformer...which is the correct way of doing what you are attempting to do...you did raise the question as to the existence of the technical short comings in comparative products that you brought up. You should be careful about doing that if you have issues with specific's. Link to comment Share on other sites More sharing options...
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