Topic: A way to maximize your speakers

[rascal101]

Yes. One way to maximize the potential of our speakers is by input signal "manipulation". This is very similar to crossover selection.

Just wanted to share the modification I did with my low cost Intex PC speakers. Please take note that this modification can also be applied to your audiophile and car speakers  

What about the circuit?
We just want to add a snubber circuit (on top of the coupling capacitor, which is the back to back electrolytic cap) to reduce peak voltage and control voltage decay. In other words, a way to damp some periodic signal. If you want to learn further please search online on passive rc snubber circuits.

Why?
To offset the non-linearity of your transistor, tube or gain device (specially when it is driven at the edges or extremes of its bias or gate) and to reduce or minimize the "switching" time of other devices as well eg capacitors from one state to another. And most of all, to "see" how such cheap speakers will sound with a better and "cleaner" input.

THE SUBJECT SPEAKERS

These are your typically low cost, "no need" to upgrade, "put them on the side" or "giveaway" (if you already have money) speakers. So, it is a "good" way to practice before we head on to "bigger" subjects  

Front



Back
- There are four screws for each speaker



"Opened" speakers
- Please take note that the transformer of the leftmost speaker is in parallel with the unshielded voice coil magnet. We will need to shield the voice coil magnet.



The components
- These parts are practically available in all electronics parts stores
- Resistors: you should use higher wattage resistor eg 10W if your speakers are 30W or higher
- Electrolytic capacitors: you can use 220uF/63V or 330uF/63V or higher voltage rated
electrolytic capacitors instead of 270uF (if not available)
- Not exactly top of the line but this isn't really about whether it is or not but rather to see how the snubber works. You can upgrade the parts later  



Connecting the components


Note: It is the + polarity of the electrolytic capacitors that is connected or wired together.



Wiring the components to the speakers

Left Speaker


Right speaker



Shielding the leftmost speaker
- Just used aluminum foil  





After screwing the speakers and connecting to the PC, I can only say that the sound is ... ... I am not really a fan of SHOUTcast Radio but I am starting to appreciate it ...

You can play around the snubber resistor and capacitor values to see its effects. The above values were selected based on my calculations  

Thanks for viewing  

[rascal101]

The technique discussed here isn't novel or unique as it is standard practice in feedback loop (compensation), power supply electronics (reduction of pri and sec voltages) etc however, should you use it as described here please give credit where credit is due specially if you want to use it for business - no problem if for personal use. Also, if you've already been practicing this for some time now, go ahead with your practice - don't mind me  

[bass_nut]

TFS brother Mel !!! 

now where did i put that soldering gun ? 

Cheers !!!

[rascal101]

Thanks Brother Fer 

[joey]

will try this later... dami ko nakatambak speaker dito office.... saan na kaya yung mga yun....

[odyopayl]

Nice one Mel!
Let me try it!

[Pandidoy]

Hehe ok yan sir Mel

[audiojunkie]

Nice! any specific brand or type of speaker?

thanks!

[rascal101]

No particular brand of speakers. Any one will do.

BTW, it is usually the tweeter that comes with the coupling capacitor. Usually, polypropelene capacitors are used. You can tap your passive rc snubber at both ends. If your tweeter still sounds "bright", increase the snubber resistor for example from 3.9ohms to 6.8ohms or higher. If you hear that notes are still somewhat extended lower the snubber capacitor for example from 220nF to 150nF.

You will observe that lower values on the snubber resistor will result in "brighter" sound while higher values results in "duller" sound due to the decrease and increase, respectively of voltage across the snubber circuit. Further, you will also observe that increasing the snubber capacitor results in notes being extended while a decrease results in notes being cut early (little or no extension). This is due to the increase and decrease of the RC time constant, respectively.

Play around with the values to get a feel of your speakers 

[audiojunkie]

Thanks! for the explainations... time get parts and play around...     

[Schrodinger's cat]

Very nice and clear tutorial sir! helpful for us non-electronics guys.
Will try this on my klipsch pc speakers 

[rascal101]

Thanks Guys  

Please advise the results of your experiments so that we can come up with standardized values for the snubber resistor and capacitor.

There is still one more simple "trick" based on some previous experiments on speakers but I'll just discuss that later  

[boomjam]

This is very good advice to us who can't seem to get the right sound we want!  In other words, may SARS! . . . heh heh heh.  Thanks Mel for the technique.

[rascal101]

Nice to hear from you Jim   BTW, how are your coax speakers?

[monreq]

I tested this modification in my rear spkr Targa 2 way Xseries. It has only 1 Bennic Cap..so I just parallel d in series 5w 5kohms resistor+203kohms 50v mylar with  polyropylne/metal caps in parallel. I dnt hav an external amp so i rely on my Pioneer H.U. My tone controls r set to  flat and EQ.is Natural mode. I playd bak an old RnB disc, d rear speakers kicks bass and sings lyk having an external amp. HF and MidFREQ.r clean and more natural. LF is define. My only problem is d vibration of LF inside my car. It's like setting a subz to 45hz xover freq., i think.
Anyway, the modification is cheap but good quality. I never believe it, until i try it.
Thanks Melanio este Melencio pala.

[rascal101]

Melanio hindi Melencio   Binuo mo pa. Thanks Bro 

Monreq (Targa X series)
Snubber resistor: 5ohms 5W
Snubber capacitor: 203K - 20nF "K" (10% tolerance)

[jeff29jeff2002]

This is a good input... thanks sir rascal...I'll try it soon on my pc sub too.

[rascal101]

In case you may be wondering about capacitor values. I have listed below some values and how to read them.

As an example, for a Mylar capacitor with the ff: inscription 224K
- first character: 2
- second character: 2
- third character: 4 -> this denotes the number of zeroes
- fourth character: K

re-writing
2 2 0000 K

Since capacitors are usually pegged at pico or p (1 x 10^-12) farad or pF for short, we can read the above as 220,000pF. If we use nano (1 x 10^-9), we can move the decimal point 3 places to the left and we can re-write it as 220nF. Going further (as salesladies or salespeople mostly know uF or micro farad) if we use micro (1 x 10^-6), we move 3 decimal places to the left and re-write it as 0.22uF.

The K stands for 10% tolerance.

As such, 224K means any of the ff: 220,000pF; 220nF; 0.22uF

Another example, 203K

2 0 000 K

This means 20,000pF or 20nF or 0.02uF. 10% tolerance.

Last example, 154J

1 5 0000 J

This means 150,000pF or 150nF or 0.15uF. 5% tolerance.

I hope this helps 

[rascal101]

To practice and to see the effects of the snubber circuit ...

Recently modified the speakers of a portable component system - JVC PC-W222. This is being used as the sound system on our compounds water station. It was ravaged by Ondoy and was recently repaired. I can now hear good music at our house which is 2 houses away  

JVC PC-W222



Close up of the speaker



Modification to the speaker



Values used:

Back to back 270uF/63V electrolytic in parallel with 1uF/63V Mylar capacitor

Snubber circuit

Snubber resistor: 3.9ohm 5W
Snubber capacitor: 224.7nF
- 220nF "K" grade Mylar capacitor
- 4.7nF polypropelene capacitor (Ero F1710-247)

Next up ... My Dad's Sony HTIB speakers ...

[audiojunkie]

sorry for  this enosenting tanong...

any major major effect sa sound quality after the mods? posible to give brief comparison bet. stock & modded po'.. Thanks!

[rascal101]

I am not much into reviews but the sound quality is better - mas buo iyung tunog. This is just my personal opinion ... If I have to compare, without is like having minor astigmatism (grade of 75 or 100) - you can focus but after about 15 - 30mins your eyes get tired and with is like having corrective lens.

If you have some time and willing to do some work please try it yourself so you can have better feel   For me, it's very difficult to give subjective feedback. Much better to discuss technically  

Anyway with parts cost of less than Php 50.00, I think it's worth spending time and effort.

[rascal101]

You don't have to open your speakers. You can do something like this.

From amplifier speaker terminals

+ spkr terminal  <---------------> snubber circuit -----> + spkr connector

- spkr terminal  <-----------------------------------------> - spkr connector

Please take note that the <----------> are speaker cables

This way the snubber circuit is external and you can compare with or without it much more easily.

[pabili]

But sir rascal, I know all standard amplifiers today has output snubbers already in the speaker path!

Or are you just saying adding more snubbers will further clean the signal?

[rascal101]

I think you may be referring to feedback compensation on the amplifiers which is a standard circuit. The component values for feedback compensation are different from snubber circuits. For amplifiers, usually it is just a choke at the output.

[rascal101]

Also, it may be possible that one snubber circuit is not enough to reduce and damp high frequency signal to required. So, another snubber circuit added to the speaker helps. If you look at the snubber resistor values used here it is usually less than the ones used on some power amps which is akin to slight peak voltage reduction or making things "just right".

Further, I'm sure you'll agree that not all people can afford the upgrade bug every now and then. So, a few pesos spent to maximize your system is certainly much more cost effective than hundreds or thousands of pesos 

[bass_nut]

You don't have to open your speakers. You can do something like this.

From amplifier speaker terminals

+ spkr terminal  <---------------> snubber circuit -----> + spkr connector

- spkr terminal  <-----------------------------------------> - spkr connector

Please take note that the <----------> are speaker cables

This way the snubber circuit is external and you can compare with or without it much more easily.

at my very amateurish level, it was like differential calculus converted to easier algebra !!! indeed, your simplified ways very helpful for me.

many thanks kapatid Mel !!! 

[rascal101]

My problem sometimes is when I write these modifications is I try to make it a report to be submitted to a Professor. So, I fail to grasp who the real audience is. Hopefully, I can improve 

[JojoD818]

Did I get it right that this is what your saying will maximize your speakers?

[JojoD818]

But sir rascal, I know all standard amplifiers today has output snubbers already in the speaker path!

Or are you just saying adding more snubbers will further clean the signal?

That's a Boucherot cell/Zobel network on the output, though it is also a form of a snubber circuit. It is there for a different purpose, not to clean the signal.

I think you may be referring to feedback compensation on the amplifiers which is a standard circuit. The component values for feedback compensation are different from snubber circuits. For amplifiers, usually it is just a choke at the output.

Pabili is referring to the Boucherot cell (or Zobel network as it's more popularly called) which is different from the feedback compensation on amps.

[rascal101]

I believe it does.

I didn't say it was about cleaning the signal. I said better and "cleaner" signal. I said "cleaner" because the snubber helps reduce EMI emissions (Sorry but I couldn't help that my mind still rakes with SMPS).

I really didn't study much about these Zobel Networks except I read that it's used for impedance matching. But the RC circuit I'm using here is primarily for leading edge peak voltage reduction and damping. The reason I'm saying that is because you have so much noise from source to amp and you really need a way to reduce these noise without interfering with transient response of your audio system. Further, it really looks like the way we do it on power supply circuits.

You should try it