New speaker design by NOOB

[thor.zmt]

Be suspicious of any discussion which contains no numbers. Parallel resonance effects between capacitors are absolutely something you need to check when designing power distribution for digital circuits which have current draw into the hundreds of MHz range. Not so much for midrange to tweeter crossovers.

There are other factors. Allow me to wax lyrically.

Let's assume a generic electrolytic capacitor (ok, use two back to back) of 220uF each as passive Highpass in a subwoofer. ESR is ~ 0.5R each, so 1R in total.

Our Midbass + HF 2-way speaker is connected after this.

First, below the formation voltage across this capacitor set, they act as series connected capacitors. Above one capacitor will become in effect a bad diode. That's a lot of distortion.

Now, we take a 22uF MKP "bypass" capacitor with ~ 10mOhm ESR. Above ~700Hz the MKP capacitor impedance will dominate the network and it will attenuate higher order harmonics generated by the nonlinearty of the back2back electrolytic capacitor at frequencies where it's impedance dominates.

Now resonances have nothing to do with this, but Kirchoff has everything to do with it.

Randomly paralleling capacitors will on 99.9% of all cases have no results or make things worse in audio.

But acting empirically, an infinite army of monkeys randomly hitting typewriter keys for an infinite amount of time will recreate the collected works of Shakespeare eventually, all in sequence.

Of course, it is better to use a (very) limited number of engineers who know what they do over random monkeys, but engineers do not work for peanuts and few I met know what they are doing. Most believe electrons are a (real) "thing" and most even believe in "ground"... The irony kills me.

Thor

 

[thor.zmt]

I was thinking of when you tack together capacitors to make up a required value and use a very small capacitance in parallel with a very large value, each having their own RC and LC values very different - would this not affect the resultant phase angle?

Of course it will. The lumped models will likely place this into the MHz region.

When I do PCBs for 50MHz clock speed digital systems I worry greatly about this, as even 0402 size capacitors have problems at 50Mhz and that's just the fundamental!!!

For audio up to 100kHz I'm kinda blase about this. It takes a special kind of stoo-peed to get that sort of problem.

Thor

 

[JohnRoberts]

Actually, I got banned, for racism.

Apparently calling Chinese product designed by a Chinese engineer (I am arguably using the term "engineer" in the loosest possible sense) a "Chinese product designed by a Chinese engineer" is not stating a fact, but "underhand racism".

They could not find anything else to ban me for, because, unlike this bunch of audio cargo cult scientists, I get my facts right and indisputable (and I called their BS left, right front and center - on the principle that science exists to be criticised) and did make them look really bad.

So, kindly get your monkey of my back.

Thor

Hard to imagine they would find you abrasive.

Hopefully we are a little more accommodating than that.

JR

 

[thor.zmt]

Hard to imagine they would find you abrasive.

Really? I'm kinda a generic no nonsense guy. I have limited tolerance for BS.

Back as "military specialist" for a contract outfit in west Africa I specialised in comms and in shooting child soul-jahs straight through the tree they where hiding behind using AP ammo.

Short sleeve? Long sleeve? Do we rape your 5 year old daughter or you? I never forget 'dem eyes. I never saw in people that were technically alive with eyes as dead ever since. And I tend to hang out rough.

After seeing what the same children had done in some of the village we marched through, sweating like Pigs in our body armour, with natives to carry the heavy stuff, well after that I had zero compunction shooting them.

I'm more worried about my Karma when I shoot pigeons that shit on my back porch and my way to my pool. I hate stepping on bird poo going half drowsy for my wakeup swim.

Hopefully we are a little more accommodating than that.

We here are mostly a different generation. We believe in lively debate. And that experience means anything.

I disagree with you a lot, but I hope I do so on facts and without insult.

Mind you, insult me all you want, I'm more worried about AK-47 bullets and terrified about artillery and heavy machine guns.

Thor

 

[abbey road d enfer]

There has been a lot of discussion regarding the effects of parallel capacitors in crossovers to improve performance, including drawbacks of using different values in parallel. Example:

https://www.tnt-audio.com/clinica/caps_parallel_e.html

You should realize this is perfect BS standing on no objective measurements, invented to justify the existence of an audiophool magazine.

I’m not sure Kirchoffs loop rule applies so well to circuits with crossover inductors and voice coil inductors moving in a magnetic field - maybe Faraday might be a better choice:

This guy does not explain why applying Kirchoff is "wrong". The beauty of Kirchoff's laws is they apply to any circuit, either in permanent or transitory regime.
Faraday is irrelevant here. If the circuit was extremely large, we may have to involve Maxwell.

I find it amazing that this guy - how did he become a professor is beyond me - manages to confuse things.
Claiming that Kirchoff is wrong when Faraday is correct is utterly shocking when it turns out both give the same result.

 

[abbey road d enfer]

I was thinking of when you tack together capacitors to make up a required value and use a very small capacitance in parallel with a very large value, each having their own RC and LC values very different - would this not affect the resultant phase angle?

You seem to consider that phase angle is an intrinsic value of a capacitor and that connecting different capacitors result in conflicting phase issues. This is not so. Of course the phase angles in the different capacitors of a parallel arrangement can be different, and then what?
Typically, in a passive x-over, the "phase angle" in capacitors is very different than that in inductors or resistors. Does it result in fighting? No, on the contrary, they work together.

 

[Disco Volante]

Whooa, another thread gone way into the bushes...

Adam, as regards distortion: get a miniDSP mic, REW, and a soundcard to generate your sweep (don't trust the internal soundcard in whatever laptop you may own...). You will probably find that distortion is dependent on many factors...
Building speakers is fiddly, timeconsuming, iterative, irritating, mindboggling and lots of fun.

You don't need expensive drivers, as others have already stated. You need measuring gear.

Happy tinkering
V!

 

[MidnightArrakis]

I don't know how you're doing it, but the text on your posts is quite a bit larger than anyone else's - comes across as a bit 'shouty'.

[the text on your posts is quite a bit larger than anyone else's] -- The default text size under the "tT" symbol is -- 15 --, but I prefer to use the size -- 18 -- for those of us here on this forum who are older and may have a problem focusing and reading a smaller text size. Even though I have and use a 34" monitor for all of my CAD-design engineering work, reading small text is still difficult. If you don't like my text size, then don't read my postings!!! Besides.....I thought all of you younger generation people were all for "EQUITY", "INCLUSION" and "DIVERSITY" in life and everything that you do!!!

[comes across as a bit 'shouty'] -- Well.....I suppose you can interpret a larger text size as being "shouty", but if I wanted to "shout" something out..........I'LL LET YOU KNOW, OK???

/

 

[Adam Frandsen]

Decided to finalize the initial build of my original post, and it ended up looking like this, I will make another with cheaper drivers and then decide which one to actually build:

---

**Final Speaker Build: Crossover Network and Enclosure**

**Crossover network for Bass Driver and Mid Woofer:**

1st crossover point at 193Hz (Impedance for both drivers: 4.5 ohms):

1st stage (Q = 0.541):
- Capacitor C1: 270 nF, minimum 100V
- Inductor L1: 2 mH, minimum 250W

2nd stage (Q = 1.306):
- Capacitor C2: 110 nF, minimum 100V
- Inductor L2: 2 mH, minimum 250W

**Impedance Compensation Network for Bass Driver:**

- Inductor L3: 1.5 mH, minimum 250W
- Capacitor C3: 470 nF, minimum 100V
- Inductor L4: 0.8 mH, minimum 250W
- Capacitor C4: 1 μF, minimum 100V
- Inductor L5: 1.2 mH, minimum 250W
- Capacitor C5: 680 nF, minimum 100V

**Frequency Equalization Circuit (Shelving Equalizer) for Bass Driver:**

- Resistor R1: 5.6 Ohms, minimum 250W
- Capacitor C6: 33 μF, minimum 100V

**Crossover network for Mid Woofer and Mid Tweeter:**

1st crossover point at 1070Hz (Impedance for Mid Woofer: 5 ohms, Mid Tweeter: 4.5 ohms):

1st stage (Q = 0.541):
- Capacitor C7: 33 nF, minimum 100V
- Inductor L6: 0.4 mH, minimum 250W

2nd stage (Q = 1.306):
- Capacitor C8: 27 nF, minimum 100V
- Inductor L7: 0.85 mH, minimum 250W

**L-pad Attenuator for Mid Tweeter:**

- Resistor R2: 1.5 Ohms, minimum 250W
- Resistor R3: 47 Ohms, minimum 250W

**Crossover network for Mid Tweeter and Tweeter:**

1st crossover point at 7500Hz (Impedance for Mid Tweeter: 4 ohms, Tweeter: 3.5 ohms):

1st stage (Q = 0.541):
- Capacitor C9: 6.3 nF, minimum 100V
- Inductor L8: 0.046 mH (achieved by a parallel combination of 0.1mH and 0.05mH, then adding a series combination of 0.01mH and 0.003mH), minimum 250W

2nd stage (Q = 1.306):
- Capacitor C10: 3.4 nF, minimum 100V
- Inductor L9: 0.033mH (achieved by a parallel combination of 0.1mH and 0.05mH), minimum 250W

**L-pad Attenuator for Tweeter:**

- Resistor R4: 1.8 Ohms, minimum 250W
- Resistor R5: 33 Ohms, minimum 250W

**Cabinet and Driver Placement:**

- Cabinet External Dimensions: 140cm (H) x 50cm (W) x 60cm (D)
- Cabinet Internal Dimensions: 136cm (H) x 46cm (W) x 56cm (D)
- Mid-woofer Enclosure Internal Dimensions: 42.5cm (H) x 40cm (W) x 10cm (D)
- Material: 50mm MDF

**Driver Placement:**

- Mid-woofer: Located 5cm from the left side and 20cm from the top of the baffle (center-to-center)
- Mid-tweeter: Located 5cm from the left side and 30cm from the top of the baffle (center-to-center)
- Tweeter: Located 25cm from the left side and 55cm from the top of the baffle (center-to-center)
- Bass Driver: Located 25cm from the left side and 110cm from the top of the baffle (center-to-center)

**Stand:**

- Height: Approximately 11cm, to elevate the speaker such that the tweeter is at the listening height of 121cm from the ground

**Ports:**

- Bass Port: Located at the back of the cabinet with a diameter of 10cm and length of 12.8cm, tuned to 20Hz
- Mid-woofer: No port as it's a sealed enclosure

 

[abbey road d enfer]

Decided to finalize the initial build of my original post, and it ended up looking like this, I will make another with cheaper drivers and then decide which one to actually build:

---

**Final Speaker Build: Crossover Network and Enclosure**

**Crossover network for Bass Driver and Mid Woofer:**

What does it mean?
Is it the low-pass on the woofer or the highpass on the lowmid?

1st crossover point at 193Hz (Impedance for both drivers: 4.5 ohms):

1st stage (Q = 0.541):
- Capacitor C1: 270 nF, minimum 100V
- Inductor L1: 2 mH, minimum 250W

2nd stage (Q = 1.306):
- Capacitor C2: 110 nF, minimum 100V
- Inductor L2: 2 mH, minimum 250W

Assuming you mean uF instead of nF, the response is not at all what you think. It gives a high-pass with a very sharp 12dB peak at 190Hz. I don't think you want that.
Now, assuming again that the inductors are in series and the capacitors are shunt, it gives a 4th-order lowpass at 390Hz. Again I don't think it's what you want.
Anyway, cascading two CL or LC filters results in a 4th-order response.

I won't dissect the other sections because they are fraught with the same issues. A high-pass filter must be complemented with a low-pass on the adjacent speaker, which you have not done.

You would make it much easier for us to help you if you joined a schematic, even a hand-drawn one.
A picture is worth a thousand words.

 

[RoadrunnerOZ]

You seem to consider that phase angle is an intrinsic value of a capacitor and that connecting different capacitors result in conflicting phase issues. This is not so. Of course the phase angles in the different capacitors of a parallel arrangement can be different, and then what?
Typically, in a passive x-over, the "phase angle" in capacitors is very different than that in inductors or resistors. Does it result in fighting? No, on the contrary, they work together.

I’m thinking that when you have two capacitors in parallel one with high esr low inductance and another with low esr high inductance the resultant phase angle at the junction would be different to that of a single capacitor with lower esr and higher inductance than the combined.

 

[abbey road d enfer]

I’m thinking that when you have two capacitors in parallel one with high esr low inductance and another with low esr high inductance the resultant phase angle at the junction would be different to that of a single capacitor with lower esr and higher inductance than the combined.

Of course the resultant impedance of two or more capacitors in parallels is different than that of a single capacitor, just like the impedance of an electrolytic cap is different than that of a film cap, but the differences for audio frequencies are generally negligible.
And don't forget that the current going through a capacitor depend as much on the capacitor than on the rest of the circuit.

 

[thor.zmt]

Decided to finalize the initial build of my original post

Please run everything through vituixcad, before spending money. If you build what you wrote up the results will not be very good, you would be much better buying the current budget favourite Sony bookshelf speakers and a pair of decent subwoofer with the money you intend to spend.

You could then try to modify the Sony speakers, I always recommend lining the interior with ceramic tiles (cheapest blowout ones from your local home improvement emporium) to add weight and stiffen the walls. Or use 12mm stone slabs as "Applique" reinforcement. Using stone cladding on the outside has the added benefit of a massive visual upgrade over imitation veneer vinyl wrap.

Use Basotect foam as fill. This I commonly recommend for many of the affordable active monitors.

Modify the active subwoofers in a similar way.

There are also crossover modifications offered on line for the small Sony's.





Spending your money this way will result in giving you an immediately working system with the possibility to improve it over time to be excellent.

With the skills you learn you may decide to tackle a big project later or decide that it is way too big to pull off well and let it be.

Thor

 

[RoadrunnerOZ]

Of course the resultant impedance of two or more capacitors in parallels is different than that of a single capacitor, just like the impedance of an electrolytic cap is different than that of a film cap, but the differences for audio frequencies are generally negligible.
And don't forget that the current going through a capacitor depend as much on the capacitor than on the rest of the circuit.

I always think it’s an interesting topic as there are many divided schools of thought. I’m just wondering what the net pass through is for two unlike caps compared to a single cap of the same sum value. Does the frequency range get extended. Is there high frequency distortion due to the difference in the caps - I know this occurs in very high frequency stuff but how much does it affect audio. Frequencies of up to 60KHz can have an effect when you look at the harmonic step down. All in all probably too little a difference to actually hear.
It’s probably a bit like going to the n’th degree with reducing cable capacitance in 500mm cables in a hifi by spending $2K on a coupling cable - the difference would probably be in the 100ths of a picofarad.

 

[abbey road d enfer]

These idiots could not see a 3-way x-over if it bit their ass.
Whatever they say, it's a 3-way system.
The second one, in particular, makes a number of assumptions that show he does not really master the basics of electronic circuits.
He just plays with his simulation software and extrapolates.

 

[abbey road d enfer]

I always think it’s an interesting topic as there are many divided schools of thought. I’m just wondering what the net pass through is for two unlike caps compared to a single cap of the same sum value. Does the frequency range get extended. Is there high frequency distortion due to the difference in the caps

It doesn't work like that. Capacitors do not have an intrinsic sound or an intrinsic frequency response.
They react with other components of the circuit.
So yes, two capacitors in parallels react with each other, but not in a conflicting way, rather in a complementary way.

- I know this occurs in very high frequency stuff but how much does it affect audio. Frequencies of up to 60KHz can have an effect when you look at the harmonic step down. All in all probably too little a difference to actually hear.

Do you hear anything at 60kHz?

It’s probably a bit like going to the n’th degree with reducing cable capacitance in 500mm cables in a hifi by spending $2K on a coupling cable - the difference would probably be in the 100ths of a picofarad.

Which, whatever snake oil aficionados claim, results in no perceptible difference at all.

 

[thor.zmt]

These idiots could not see a 3-way x-over if it bit their ass.

Well, each tweeter only has a highpass. So technically it 2.5 way, not 3 way. Or even more precisely, a 2 way speaker with a super tweeter that is mostly active above the audible range.

What is actually done is to bring in the super tweeter at a fairly high frequency, to widen the dispersion at very high frequencies. Green is the "super tweeter" crossover red and blue are HF and LF respectively.

Whatever they say, it's a 3-way system.

Why? Because it has three drivers?

The second one, in particular, makes a number of assumptions that show he does not really master the basics of electronic circuits.

That is your view. My point is that there is quite a bit of information on line.

He just plays with his simulation software and extrapolates.

That is what he says he does...

Thor

 

[abbey road d enfer]

Well, each tweeter only has a highpass.

This is not what I see in the schemo at 1mn 10s in the video, neither in the frequency responses. The 1st tweeter has both a high-pass and a low-pass.
So, in my book it makes a true 3-way system.
Now, I don't know these speakers, never seen them, nor heard them, nor measured them, never retro-engineered them, so, if this schemo and these responses are not authentic, what's the point of publishing them in a video?


abbey road d enfer said:

He just plays with his simulation software and extrapolates.

That is what he says he does...

A good reason for not listening/viewing.

 

[JohnRoberts]

I did my own bench testing on parallel caps back in 70s when I discovered phase errors in a RIAA phono preamp in the top octave caused by aluminum electrolytic capacitor's ESL. This top octave phase shift was measurable but not audible (tens of degrees at 20kHz). That capacitor was in the ground leg of a non-inverting RIAA preamp stage, so something like 360 ohms in series with 22uF.

From my bench testing I empirically determined that a parallel film cap needed to be 10% of the total combined value to effectively behave like one large film cap. This is contrary to the popular wisdom that suggests much smaller value film capacitors in parallel with large electrolytic caps could make audible improvements.

Coincidentally I also determined that a 22 uF tantalum capacitor also delivered better top octave phase response than the aluminum electrolytic cap. Since this preamp stage was inside on of my kit products, I did a mailing to a sample of my kit customers where I sent them 22uF tantalum caps to substitute for the aluminum caps in that preamp stage. Most of the customers who responded, claimed that the difference was a positive improvement except for one customer ( a well known sound engineer for a popular band, now RIP ) who informed me that he knows tantalum caps are awful in audio paths, so he declined to try it.

I make no claims that the tantalum sounded better than aluminum in this application, I only know it delivered better measured phase response at 20kHz. FWIW the tantalum cap was several times the size of the aluminum, but it was higher voltage cap. I could have received the positive feedback from my customers due to expectation bias. I could measure but not hear a difference personally.

My design philosophy has always been if you can measure an error, fix it. I have long been able to measure stuff that I couldn't hear.

My sundry future phono preamp designs avoided that topology for that and other reasons.

JR

 

[abbey road d enfer]

I did my own bench testing on parallel caps back in 70s when I discovered phase errors in a RIAA phono preamp in the top octave caused by aluminum electrolytic capacitor's ESL.

The effects of ESR and ESL are pretty well known and predictable, if not quantatively but qualitatively. It is clear that the diferent types of capacitors have largely fiffering parasitics, which makes some less desirable than others.

rom my bench testing I empirically determined that a parallel film cap needed to be 10% of the total combined value to effectively behave like one large film cap. This is contrary to the popular wisdom that suggests much smaller value film capacitors in parallel with large electrolytic caps could make audible improvements.

I say the difference between sagesse populaire (popular wisdom) and sagesse (wisdom) is the same that the difference between soupe populaire (soup kitchen) and soupe (soup).