Serial Xover considerations

[Elgen]

I have ordered Smalls article on serial crossovers att AES and wonder what to consider when constructing such device?

I'm attracted to the fasrespons but fear of the complications when designing it. It not so straightforward as a parallel one.

[rabbitz]

Have a look at Andy (the wise one) Graddon's site for information on series crossovers.......also has a speadsheet that calculates starting values.

http://users.tpg.com.au/users/gradds...ross-overs.htm

[Andy G]

"The Wise One" ??? are you sure you are referring to me ???


Elgen.... lots of reading.... but if you still have questions when finished, I'll try to help !!

Have fun !! and Enjoy the music !!!

[Elgen]

I have studied the articles and made a drawing of a possible threeway linked serial network with a parallel circuit for a backthrow tweeter.
I haven't made any calculations so far but with some support and further studies I will soon do that.
I once owned the Small article from 1971 but lost it before I had the chance to get into the subject, and I admit that I also was to bored and lazy to take the time. But this time I will do it seriously.
For my speakers and if the budget allows I will use Thiel & Partners elements:

C12/6 25 mm Tweeter 2.2 - 40 kHz / 89 dB
For backthrow tweeter, with constant impedance pot to adjust the ambience from the speaker.

C13/6 25 mm Tweeter 2.5 - 40 kHz / 92 dB
Frontloaded.

2x C44/8 50 mm High Midrange 1.0 - 15 kHz / 89 dB
Two of them to increase sensitivity.
They have a wide bandwith and very flat frekvencyrespons witch are ideal for serial networks acording to the articles.

C220/T6 8" Bass - 2,5 kHz / 90 dB
They have good sensitivity and give deep bass.

This will give a loudspeaker with low coloration, high bandwith, high sensitivity, good phase and transientrespons.
And hopefully better soundstage than my Cerwin-Vega V-15F that I currently use!

[sobazz]

Andy, since you are the wise one you should be able to give me a hint on this - the 2-way crossover.

What is the cross frequency of that filter? The slope is a pretty awkward 9db, or?

[Andy G]

.. as I tried to say earlier..... I am not "the wise one" , I'm a collector of info, and an experimentalist !!

OK !

the LC Audio, as far as i can figure is around 2500Hz, at somewhere near 9dB. I've tried it, and found it very difficult to tweak, and also difficult to alter the x-o point. which for me, made it not very usable ! Even when i used drivers that should have been about right for that x-o, I was always able to get a normal series to sound way better.. IMO

[Andy G]

.. those drivers look as though they could be made to work, I hope you have modelling software to get some idea of what is actually going on.

I would try the "linked" version of the 3-way, and just use a simple parallel on the rear tweeter (although I don't think its really necessary....rear tweeters to my way of thinking will just confuse the sound.. which I guess is what ambience is !!!)

I would be interested to see what x-o point you use.... the drivers seem to indicate the lower x-o point will be somewhere around 1k-1.5k, I hope that doesn't cause a problem through the fundamental vocal range.

A 3-way as your first "series x-o" is a very brave move....GOOD LUCK !!

[rabbitz]

Originally posted by Andy Graddon
.. as I tried to say earlier..... I am not "the wise one" , I'm a collector of info, and an experimentalist !!

Alright Andy...... I'll call you the "caretaker of series crossovers".

When I see series xo's used by others, it's always thanks to AndyG. Without your stuff we'd be RS as it's very hard to find good useful info on series xo's........ and thank god for your spreadsheet.

Keep collecting.....

[sreten]

Originally posted by Elgen
I have studied the articles and made a drawing of a possible threeway linked serial network with a parallel circuit for a backthrow tweeter.
I haven't made any calculations so far but with some support and further studies I will soon do that.
I once owned the Small article from 1971 but lost it before I had the chance to get into the subject, and I admit that I also was to bored and lazy to take the time. But this time I will do it seriously.
For my speakers and if the budget allows I will use Thiel & Partners elements:

C12/6 25 mm Tweeter 2.2 - 40 kHz / 89 dB
For backthrow tweeter, with constant impedance pot to adjust the ambience from the speaker.

C13/6 25 mm Tweeter 2.5 - 40 kHz / 92 dB
Frontloaded.

2x C44/8 50 mm High Midrange 1.0 - 15 kHz / 89 dB
Two of them to increase sensitivity.
They have a wide bandwith and very flat frekvencyrespons witch are ideal for serial networks acording to the articles.

C220/T6 8" Bass - 2,5 kHz / 90 dB
They have good sensitivity and give deep bass.

This will give a loudspeaker with low coloration, high bandwith, high sensitivity, good phase and transientrespons.
And hopefully better soundstage than my Cerwin-Vega V-15F that I currently use!

You are not considering Baffle Step Compensation.

If 89db is one midrange sensistivity, you only need one.

With some BSC midrange sensitivity required will be 85/86 dB.

Your other choice is to use two bass units in parallel, with two
mids and one tweeter. Midrange sensitivity will be 6dB higher.

sreten.