Apollo Construction Diary

[Boden]

Guys,

As usual for DIY, extraordinary attention is paid to driver hardware, cone materials and manufacturers. The so called "driver A sounds mucht better than driver B" argument is without any merit. This is invariably an apples vs oranges type discussion.

These statements should be taken with a grain of salt, and can only be established if level and filtered acoustic output of driver a and driver B are identical, otherwise you are actually listening to filter or level caused differences. Even 1.5 dB makes a difference.

Use 2 rather different, say and AT and a SB 6.5" midwoofers with not too exotic SPL characteristics, and somewhat comparable T/S parameters, put them in identical boxes, apply UE and turn both into textbook acoustic output 4th orde LR lowpass drivers.

You wil be uttery surprised how similar they will sound. But then again,this experiment can only be done if both drivers are physically comparable and, qua acoustic output after filtering, identical.

So : direct improvement of driver A over driver B ? It is all very subjective.



Kind Regards,

Eelco

[Helmuth]

I had this experience with tweeters. I bought a very nice ribbon Swans RT-1 and placed them in the monitor with then current visaton DSM25FFL dome. I had one with dome and one with ribbon. If I didn't knew it I would not hear a difference in these drivers. When buying the ribbons I though they would improve the sound much on the more common titanium-dome.

On the other side I hear a difference with every material change in driver , resistor, capacitor or cable. And we are listening to the mix of them it is like cooking to make the right recipe.

There are other who will step over this and say they applying physics and math theory and claiming they know best. What in many ways is much to simple because they do not know where their model fails.

Then the attraction of nice looking expensive drivers with a good technical story witch also attract me. What really would be interesting what will be audible in the comparison of the AT of 300,-Euro to the 50,- Euro monacor. Warning using cheep drivers doesn't help in claiming one build a top performing system.

[Boden]

Helmuth,

When comparing dome tweetres and ribbons you are again comparing apples and pears, because the off ais charactristcs are widely dissmuora. For a proer comparison the physicallay outr and dmensons ( hence my 6.5 midwoofer suggestion) must be comparable.

Over te last 20 year I have measured and tinkered with literally hundreds of drivers. I do not share the view that resistors, caps cause differences. Once levels are carefuly equalized/matched ,virtualy any difference vanishes ...

Kind regards,

Eelco

[Helmuth]

Check the RT1 and the dsm25ffl will not be far of what dispersion is concerned, and I can only say it surprised me to I did hear almost no difference. (It becomes OT now sorry.)

[Boden]

Oops, sorry too quick: read:

off axis characteristics of domes and ribbons are widely dissimilar, especially vertical. For proper comparison the physical lay out and dimensions must be roughly comparable.

I would high encourage the AT vs. Monacor experiment. However, this will only work if you use filter simulation software equipped with an Optimizer.

I will gladly offer help and input. I can assure you, you will be pleasantly surprised about the results of this comparison.

Regards,

Eelco

[ShinOBIWAN]

Originally Posted by Boden

Once levels are carefuly equalized/matched ,virtualy any difference vanishes ...

Kind regards,

Eelco

Thing is you need to go active DSP to effectively sort deviations between two similar drivers and even then there are still differences. This isn't going to be common place and so swapping drivers is more apparent. After all most speakers are passive.

I use a DEQX most of the time and with this tool you can achieve very close tolerances when assessing drivers within a design. My thoughts on what your suggesting are that the overall tonality of sound maybe similar but for me there's no denying changes in apparent details as well as shifts in the stereophonic parameters.

With what I say here I'm talking about a complete design and not just trying to assess a driver in isolation.

[Helmuth]

Originally Posted by ShinOBIWAN

Thing is you need to go active DSP to effectively sort deviations between two similar drivers and even then there are still differences..

What kind of differences will be audible is the question, or would something like the shape of the used baffle be more leading. For what the end result concerns.

[ShinOBIWAN]

Photo of the AT 5":

[Helmuth]

Originally Posted by ShinOBIWAN

Photo of the AT 5":

Weight?

[ShinOBIWAN]

Originally Posted by Helmuth

Weight?

I'd guess around 5kg