Completely impressed and saddened by DIYaudio

[scott wurcer]

And Windoz only

dave

I guess you'll have to stick with "Pure Vinyl" I am surprised at an Apple only software house.

 

[planet10]

I guess you'll have to stick with "Pure Vinyl" I am surprised at an Apple only software house.

I do have Pure Vinyl on the shopping list... just need to get Leopard on the dedicated music G5 iMac.

On the 2nd, i just can't be bothered using 3rd rate OS software (having to use Excel or occasionally Word is enuff torture for me). Nothing has been mission critical enuff to warant accepting any of the free Windows boxes i get offered all the time.

dave

 

[sumaudioguy]

Even with the best of simulations things can still go worng.

Nothing beats the man with a handful of capacitors tweaking a VAS or quasi lower driver !

For impedance compensation used with passive crossovers the elctrical models only give a starting point so you are sooooo right. Dialing in the series resonator to compensate for driver resonance and the RC for rising Z at high frequency in the lab is the only way to achieve a good match. Have cap decade box and power potentiometers for exactly that purpose.

As a note: I set up the same rig for measuring Z of the driver in test and then set the oscillator to sweep the frequency range of interest. Then start adjusting the LRC and RC until the phase of the input signal and the phase across the driver with compensation networks are in phase over a bandwidth much wider than the driver will be used or as good as possible. Next again measure the Z as described in the earlier post and "discover" what the effective "R" of the composite (driver plus networks) is and use that value for passive crossover design. This works really well. In testing the results come out very close to the theory for the crossover part.

See the patents 4198540 and 3457370 for history.

 

[sumaudioguy]

I do have Pure Vinyl on the shopping list... just need to get Leopard on the dedicated music G5 iMac.

On the 2nd, i just can't be bothered using 3rd rate OS software (having to use Excel or occasionally Word is enuff torture for me). Nothing has been mission critical enuff to warant accepting any of the free Windows boxes i get offered all the time.

dave

Vinyl is cool!

Really do not believe anyone here wishes to argue an OS choice. Personally I do not care what OS it is at all. The only thing important is "Will the OS run the software I wish to use." That is all that truly matters. If you do not wish to run a particular software that is your choice. I run the OS the software ask for.

 

[speakerman]

Response to your original posting "Completely impressed and saddened by DIYaudio"

Hi, Sumaudioguy -

I harkened to your aphorism "People do not care about facts - people only wish to feel good about what they believe."

I recently read a similar statement "People do not love Truth; they only want to make what they love the Truth."

Sad but true.

I am new to the diyaudio website. My main interest currently centers on Transformers, particularly design and physical winding of step-up transformers for use in ESLs (ElectroStatic Loudspeakers). Been learning much and reading about different approaches and ideas.

If you know of any Transformer Design software, please let me know. If any other members reading this thread know of Transformer Design software they can recommend, I welcome hearing from you all.

Best Regards,
Angel

 

[7n7is]

Old sad things.

Old Sad Things - a set on Flickr

Old Sad Things

 

[speakerman19422]

RC circuits are a good way to match frequency response in crossovers by lowering the tweeter's response above resonance. There is to much hype over many designs. When it comes to cone material.voice coil former materials, crossover types and cabinet loading.. Companies have to make a profit and compromise because of liscensing fees. My son's computer speakers have a ring radiator tweeter. Much can be learned by examining some of the old designs that were new break throughs at their time.

 

[sumaudioguy]

An old thing... Recall reading the article about an "early" PA loudspeaker- I think 1932 using 2 straight horns for 80-8000Hz. The mouths of the two horns were aligned while the drivers were offset by many feet. This proved acceptable until one day a tap dancer was used with the PA. The driver offset made the effect of machine gun fire. This resulted in moving the one shorter horn back so the drivers were in alignment. Learned something that day... drivers need to move together in the same direction at the same time.

It is pretty difficult to invent anything in audio anymore. It is more a matter of technique to build a speaker box that does not rattle or an amplifier that is absolutely stable. Not much in "new" is available other than parts get a lot better like caps and transistors. Drivers are much the same as for the last 60 years or more. Different magnets though most still use ceramic 5.

What has changed is the amount of computer simulation that can be helpful or extremely misleading. There is a lot of that on DIY and everywhere in all industry. I read a whole website on design only to learn at the end it was all simulation. The joke was on me. Being one of the first to use design and use simulations it is just the fact the simulations can very easily fall very short of the reality. I work with magnets a lot and the magnet simulations just do not work well at all with wide gaps. Finite element analysis requires each adjacent element to be different. If adjacent elements are the same an effective divide by zero occurs- whatever that means. So those who can bumble along in the laboratories and just keep trying to improve the models and make real equipment and perform real test. Some even write about it but then if it does not support "popular knowledge" that effort is almost always tossed aside. Want to know how atoms and particle waves work? Read "Vector Particle Physics" by Thomas Lockyer. It is all there and clear and concise as can be yet not many care at all as it does not support popular quantum **.

Take care and good luck playing. -SUM

 

[soongsc]

From Godfrey- You have one explanation and here more-

The air trapped between the spider and the top plate is another mechanical resonator. The air trapped between the dust cap and the pole piece is yet another. Both of these get reflected into the electrical circuit. And yet there is more as frequency increases the coupling between the voice coil and the diaphragm or cone changes which changes the reflected impedance up there. Then adjacent winding starts showing its interwinding capacitance (especially true on 4 layer VC) and so another UFO is tossed into the mix. All this is why I abandoned the reflected electrical analysis because it just got SO complex.

The dust cap one on a 2 inch voice coil is like about 400Hz. So vented pole pieces but then the vent has a tuning which changes it again...ouch!


As a note I have never seen the electrical resonance be at a lower frequency than the mechanical one.

These effect sound, and normally can be seen in CSD and sometimes SPL. I once had that kind of cavity resonance around 1KHz.