Just got a pair of FR125s - Page 2

consort_ee_um · 17th October 2006, 09:21 AM

In general it is better to flatten the peaks rather than fill in the troughs, although purists might want to do both, so here is the notch filter -
To make a 5dB notch centred on 6.5kHz make C1 2.2nF C2 820pF R1 5.6k and R2 47k
Since the self powered op-amp is not yet with us (I claim the patent BTW) I admit I forgot the power supplies to the op-amps say +/- 12 or 15V

Cyburgs · 17th October 2006, 11:35 AM

@type & @Landroval:

You are right, 5 liters will be boomy. On the other side 10+ liters is already quite big for a nice bookshelf speaker.
In order to keep it small I experimented with a highpass-capacitor to keep the bass response on a linear level.
The result is a speaker called "Cyburgs-Monitor" (uuuh.... smart name) with 6,5 liters and a quite linear bass response down to about 50 Hz.

A notch filter is added make the mids more linear.
Have a look here, this thread is unfortunately in German, if anyone is interested I will make an English translation. In the first post you will see pictures, then a plan and the frequency response.

Cyburgs monitor in hifi-forum.de

nice greetings, Berndt

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17th October 2006, 09:21 AM	#11
consort_ee_um diyAudio Member Join Date: May 2004 Location: Hertfordshire	In general it is better to flatten the peaks rather than fill in the troughs, although purists might want to do both, so here is the notch filter - To make a 5dB notch centred on 6.5kHz make C1 2.2nF C2 820pF R1 5.6k and R2 47k Since the self powered op-amp is not yet with us (I claim the patent BTW) I admit I forgot the power supplies to the op-amps say +/- 12 or 15V

17th October 2006, 11:35 AM	#12
Cyburgs diyAudio Member Join Date: Mar 2004 Location: Austria	@type & @Landroval: You are right, 5 liters will be boomy. On the other side 10+ liters is already quite big for a nice bookshelf speaker. In order to keep it small I experimented with a highpass-capacitor to keep the bass response on a linear level. The result is a speaker called "Cyburgs-Monitor" (uuuh.... smart name) with 6,5 liters and a quite linear bass response down to about 50 Hz. A notch filter is added make the mids more linear. Have a look here, this thread is unfortunately in German, if anyone is interested I will make an English translation. In the first post you will see pictures, then a plan and the frequency response. Cyburgs monitor in hifi-forum.de nice greetings, Berndt

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