BiAmp using Dx amplifiers are now ready

[destroyer X]

Of course, you can use other amplifiers... just think about into the ones are great for bass and for voices and treble.

The idea is simple, passive filters and volume control in the place of a pré amplifier..beeing passive you will not have complications, nor supply and reduced distortions (as each stage distorts).

The signal "filtered" goes to a bass amplifier, that has, as a main difference, a huge input condenser...also the gain is adjusted into the second differential transistor, the one at the feedback line...you have a resistance in series with an electrolitic condenser to ground...that resistance controls the gain... reducing it you will increase amplifier gain and sensitivity as a consequence.... of course increasing it you will decrease the sensitivity..and this is needed to match your speakers/power and volume to allow you to have a mid potentiometer position reference of correct adjustment.... so..you start there and then you tweak to compensate the music style you will be playing.

The bass amplifier, when receiving only basses, works better, distort less and sounds excelent... the supply variations may be felt by the midrange and treble amplifier...this way i suggest you to use two supplies..one for bass and auxiliary channel and other to the midrange and treble unit.

Observe that you have stereo...the bass is captured in one channel only.... you may include a "blend" resistance with a LC filter to connect those two channels together if your bass is present in one channel only.... this must be developed/created....i had not that problem here.... so...not needing i have not made that..the way sound is is perfect to me...just perfect!

But a very hard work is needed....try and error basis...to not waste your time calculating as home acoustic, the speaker enclosure acoustic, the speaker drivers..all that stuff will confuse you a lot..better to adjust to the final customer..and this guy is YOU!... and your ears.

Capacitors values, some resistances in series may adjust your own drivers.

In my case, midrange was the big trouble..the low mids... where you have the drums and some percursive instruments...i decided not to bother and i use to align or misalign the low midrange drivers pointing it to my ears or not...this is the adjustment i have decided to make...also observe the midrange i am using is outside enclosure..so..it results low efficiency as we have cancellations of phase because the speaker is not mounted as a dipole with a panel in the frontal face to avoid cancelations....you may have too much mids and may need to include series resistances with your midrange driver.

It is delicious to find the correct ballance..it is magical, because all musics plays fine when you reach the ballance..you can switch from musical style without touch the adjustment..only the CD output level is adjusted once "calibrated".

I strong suggest you to try...you will want to kiss Destroyer x...please!...a thank you is enougth...i love girls!

ahahahahahh!

regards,

Carlos

[destroyer X]

development...into a try and error basics..using ears as instruments to evaluate.

attached you have a pdf schematic.

The "perfect", or final recording was not made yet.... soon i will make something to show you quality.... and this depends on the digital camera..we have always losses...digital camera recording is not so good as a live reproduction.

http://www.youtube.com/watch?v=ACrjCMvMlXY

http://www.youtube.com/watch?v=cPqXEd1U6DM

http://www.youtube.com/watch?v=rljMY96z13M

http://www.youtube.com/watch?v=q5NVcpmoVaQ

http://www.youtube.com/watch?v=Ew7Sr1IA6h8

http://www.youtube.com/watch?v=Aybx2UVWtQ4

regards,

Carlos

[destroyer X]

It is a 20 watt LG speaker, 6 ohms impedance...was "captured" from a Philco sound system.

It is beautifull to voices and to percursive instruments, to drums and so on.

this one is not assembled into a speaker enclosure..it is free air...the adjustment is made pointing or deviating it from my ears.

My system is used together the computer, because this is the main use i have for audio.

Into my living room, satelite reception and television is plugged into a home theater.

regards,

Carlos

[destroyer X]

to publish things made by my brain, or simulators, or sketches, or ideas.

Those things i publish are tested, were assembled and listened into real life and you may have the 100 percent guarantee that will work perfectly and will sound fine!

I am a Do It Yourself man.... a real one...i use to hold the soldering iron..not a
theorical guy, or someone that goes creating into computer simulators...join the sub group of DIY forum...the real dyers.... i am proud i am one from them, a small group inside our forum...the ones build real things.

Also i use to prove what i say...i use to show pictures and videos as documents.... ensuring you the real thing, not the "imagination" thing.

regards,

Carlos

[PeteMcK]

for stereo, you'd need to replicate the mid/horn/tweeter for both channels;
Usually for systems with mono Bass, the LF signal is derived from both channels with a simple resitive mixer.
'you will want to kiss Destroyer x' - thanks, but no thanks ;-)
'very hard work is needed....try and error basis...' - a little science will mean a lot less work....
an additional way to reduce distortions is to use higher order crossovers...

[destroyer X]

Also..there are many variables to input into the formulas... acoustics, the particular speaker, that one, the enclosure, the home acoustics, my ears, my musical preference...and there's no formula to such kind of things.

Here some specifications...i am having fun adjusting my way.

Do your way PeteMcK...but do something, and publish here, as you are a very old (older than me) forum member, and you may have published several things...let us know...post links please... we will enjoy to read your ideas about.. the introduction of that "little science"

regards,

Carlos

.................................................. .................................................. ..............................

Interesting folks..the try and error listening tests made, result capacitor values not so different compared to the factory suggested values... this means human ears plus brain works...of course some help from audio generator (sinus), voltimeter and scope were present into the adjustments.

[destroyer X]

to save time.

here you see when i was watching the high frequencies crossover...not exactly high frequencies as start at 150 Hertz....one speaker reproduces 150 hertz with some losses...also that loss, the dB loss we can know using simulators.

regards,

Carlos

[wintermute]

I must say Carlos, you are fast! It is only a few days since you posted in the loudspeakers forum, and already you have built, tweaked, and have something to your liking! I only hope when I start my crossovers that I can be even 1/10th as fast, Somehow I think I will take a lot longer.

Tony.

[destroyer X]

I use to produce awfull spider things, point to point.... terrible!

Now i am adjusting to listen distant, into the living room, and without compromise too much my computer room audio.

It is hard to adjust that way...hard work for sure.... see the picture..but please, do not show folks.... a shame on me!...hehehe

It is not the final product..the mess is while adjusting, not to use soldering iron for a while...when adjusted, and finished and tested.... several days listening, then i will assemble into a board..clean and nice.

Attached the crossover modifications to "compromise" things..to my room acoustics, my ears, my speaker drivers, my musical taste too.

This crossover is to provide from 150 (with losses in this frequency) to 20K... and i am listening fine the frequency sweep in this range.

regards,

Carlos

[Bigun]

very nice Carlos, and as you say, this is a great way for us to have a reason to build extra amplifiers and play with things, experiment and not get stuck in our computer screens.