"Boutique" opamps from chinese vendors. Anyone tested?

[abbey road d enfer]

No. In the analog realm we map (for arguments sake) the range of +2.8V to -2.8V into 65k values. Digital silence is 0x0000, but negative maximum is 0x8000 and positive maximum is 0x7FFF. 16-bit samples are represented as 2's-complement signed integers, ranging from -32768 to 32767.

So the ratio between positive or negative max and digital silence is infinite, great news.
You don't answer what is the ratio between the highest possible amplitude (65535) and the smallest defined number (+ or - 1LSB). I maintain it's 65635.

Well, again. We can make highly directional speakers, which can be placed near boundaries and have a radiation pattern that stabilises the virtual sound source locations from our two channel signal across a wide lateral listening window and allows an acceptable vertical listening window.

And how do you build these hypothetical "highly directional speakers"? Don't mention ultrasonic speakers.
Many of your answers rely on fantasized concepts which may never see the light of day.

They are vastly inferior in this application to crossovers that use elliptical filters and have a 10th order higher slope in the actual crossover region

Higher slope in the x-over region is the usual band-aid for challenged speakers that have too narrow bandwidth.

and they have been repeatedly tested in blind listening tests as inferior in subjective terms to the classic 3rd order butterworth.

I have assisted and sometimes conducted tests where the common LR24 was clearly deemed superior to a 3rd-order B'worth.

 

[abbey road d enfer]

Also, a cable with a lump on it that contains electronic components is still a cable, right?

No, it's an electronic apparatus. If it has to be added, it means the system has some intrinsic limitation, that may be acceptable or not. With said apparatus, it may be capable of behaving better than without. But without may be acceptable for many. It's all a matter of performance vs. cost.

How about a cable with a Low DCR differential and common mode lowpass at 10kHz, a DC Blocker (to stop toroidal transformers from vibrating) and a earth loop breaker.

Again the hypothetical fantasy.

 

[sahib]

..........................
It often can be massively improved just by using a low impedance earth connection mains cable. I like steel armoured multicore control cables for robotics and industrial use, we get a shield, many cores of which we can connect many paralleled for super low impedance on the earth path......

How low?

For wall sockets the standard cable used is 2.5mm2.

Distance from the domestic distribution box to a wall socket can be as long as 20m (in fact our living rom is way farther than that). So, this is about 0.15 Ohms.

The earth connection resistance from the domestic fuse box to the main distribution box at the building entrance can easily be a few ohms but let's take the whole thing as 1.15 ohms from the building entrance to the wall socket.

Take an average of 2.5m for a mains cord with a standard 1mm2 cable. Ignoring the IEC and plug contact resistances this is about 0.05 Ohms.

Let's go over board and make the earth wire 4mm2. this is 0.01 Ohms.

Now, are you suggesting that reducing the earth path resistance from 1.2 ohms to 1.16 ohms will make the already faint hum disappear?

Otherwise I enjoy your posts.

 

[Newmarket]

man... i didnt want to start a war. I justed wanted to know if people used one of these components and if they were worht the couple of dollars more...

Don't worry We (well I at least) love a good veer to a degree. It can lead to some interesting places. Some contributors can "dig in" a bit. And others with "issues" might get straightforward rude. But they usually get short thrift from the mods.

 

[abbey road d enfer]

man... i didnt want to start a war. I justed wanted to know if people used one of these components and if they were worht the couple of dollars more...

Not a war, merely a skirmish. And you're not guilty. Someone else is.

 

[thor.zmt]

So the ratio between positive or negative max and digital silence is infinite, great news.

Ye, but the smallest signal that can be represented is 0x0001 or 0xF001. The result is called quantitisation noise.

You don't answer what is the ratio between the highest possible amplitude (65535) and the smallest defined number (+ or - 1LSB). I maintain it's 65635.

You are wrong. The difference between 0x0001 and 0x8000 is what can be represented. And that is 32767. It is that basic. You will find it in any basic text on digital signals and DSP, BUT (strangely not audio, as if basic laws of physics do not apply to audio).

And how do you build these hypothetical "highly directional speakers"?

Using any suitable solution. Using waveguides, arrays of drivers, whatever solution takes your fancy and delivers the required result.

One example how it COULD be done is B&O Beolab 90:

Bang & Olufsen BeoLab 90 loudspeaker

An alternative would be for example one of my custom projects that combined a sealed 12" Woofer in a concrete pipe pointing upwards and a dipole 12" placed perpendicular with independent DSP and Amplifiers to create a controlled directivity LF system and a Manger Schallwandler Wideband driver which with a suitable acoustic rear device delivers a cardioid response down to 300Hz and which by it's nature delivers constant and comparably narrow directivity at higher frequencies.

Many of your answers rely on fantasized concepts which may never see the light of day.

Really? Which ones?

Higher slope in the x-over region is the usual band-aid for challenged speakers that have too narrow bandwidth.

So you mean LR4 is a band aid for challenged speakers that have too narrow bandwidth?

Compared to first order crossovers?

I have assisted and sometimes conducted tests where the common LR24 was clearly deemed superior to a 3rd-order B'worth.

Where these tests conducted under conditions where you used two identical wideband drivers that would normally be used without crossovers where used as sound sources (to make sure you are literally comparing the crossover) or alternatively was the crossover output summed (without drivers) and then reproduced by a single wideband driver?

If not you are testing a multitude of variables and not just a single one.
In this case any preference rating applies to the complete system, not the actual specific crossover topology.

Thor

 

[thor.zmt]

Also, a cable with a lump on it that contains electronic components is still a cable, right?

No, it's an electronic apparatus.

So a cable with resistance, inductance and capacitance is an "electronic apparatus" , BUT ONLY if these elements are added and NOT if these elements are inherent to the cable?
How does one differ fundamentally from the other?

If it has to be added, it means the system has some intrinsic limitation,

Ahh, we have reached the point to accept that we are dealing with a system.

And you suggest that all well designed systems lack any intrinsic limitations and that any systems with intrinsic limitations are poor (or cost constrained) designs?

How about a cable with a Low DCR differential and common mode lowpass at 10kHz, a DC Blocker (to stop toroidal transformers from vibrating) and a earth loop breaker.

Again the hypothetical fantasy.

Nope. I designed this and actually got into pre-production stage.

Where S&M promptly decided to "disintegrate" my rather budget priced 99 USD cable with active SMPS noise suppression, Earth Loop breaker and DC Blocker and sell it as three separate products totalling 1,200 USD and making an awful mess when combined. These are for sale now, but I cannot possibly recommend the products with good conscience.

Performance improvements could be quantified using a variety of objective measurements, such as using an accelerometer on mains transformers to quantify the effect of blocking DC, using a 5GHz Analyser with generator, LISM and signal injection module to quantify the amount of RF suppression and literally the use of a USB DAC as source and the earth loop from the AP2 to quantify the effect of breaking the earth loop.

Cable naturally based on armoured, shielded industrial control cable with ferrite loaded filler.

All very real. If not for S&M playing silly buggers, I'd actually be recommend this mains cable as "all 'round tonic" for mains related issues without resorting to killing snakes and extracting their oil.

A review of the "active SMPS & RF noise killer" tech in a stand alone plugin device is here:



Very audible changes are evident that can be heard even in a youtube video. I do not recommend the product (it is overpriced) or the company (it operates by selling IP that was obtained through deception and is used without due and fair compensation).

Thor

 

[thor.zmt]

How low?

For wall sockets the standard cable used is 2.5mm2.

Distance from the domestic distribution box to a wall socket can be as long as 20m (in fact our living rom is way farther than that). So, this is about 0.15 Ohms.

This USUALLY is not relevant in our context, it is external to the network formed by audio devices, mains cables and and other interconnection cables.

Take an average of 2.5m for a mains cord with a standard 1mm2 cable. Ignoring the IEC and plug contact resistances this is about 0.05 Ohms.

The resistance for a 6.6ft with 1mm@ is 34mOhm, the contact resistance of IEC and Mains plug is usually substantially higher. Special grade (not audio, but medical/industrial) sockets, plugs and IEC's can lower this a lot.

The inductance is ~ 6.6uH.

Impedance will depend on frequency.

Now, are you suggesting that reducing the earth path resistance from 1.2 ohms to 1.16 ohms will make the already faint hum disappear?

No. Because the path you mention does not participate in our earth loop network.
It is again this argument that the 20 to the distribution box (or the km to substation and 100's km to the power station) would swamp out any difference in the short mains cable, but that misses the root causes of the problems we are dealing with.

Let me illustrate:



And we are in 2023 not just dealing with hum. SMPS in "burst mode" at low load create interesting audible noise pattern if allowed to enter the audio path and demodulated from the supersonic switching frequency.

Otherwise I enjoy your posts.

Glad to provide entertainment.

Thor

 

[thor.zmt]

about the only thing left to add here is if you can hear it you should be able to measure it.

Absolutely. There should be some way of quantifying using objective technical means what is being heard.

However there is no reliable guarantee or evidence that if all you measure is frequency response, SNR and THD you have reliably covered all audible fidelity impairments or that improving this set of common measured objective parameters beyond sensible limits result in reliable improvements in perceived sound quality.

If it measures right and sounds like shit, you measured the wrong thing.

Yup, however there is a strong undercurrent among the more objectivist minded in audio that "audio is a mature technology" and that "anything that matter is measured" and the corollary "because it is measured it always matters" which mitigates strongly against any risk of ever devising new expanded measurements that would finally show a reliable correlation with perceived sound quality.

Thor

 

[abbey road d enfer]

You are wrong. The difference between 0x0001 and 0x8000 is what can be represented. And that is 32767. It is that basic. You will find it in any basic text on digital signals and DSP, BUT (strangely not audio, as if basic laws of physics do not apply to audio).

You are mistaken. What the ear perceives is the difference between the highest and the lowest pressure, around a reference which is the athmospheric pressure. The pressure "swing" is 64k, and the minimum valid swing is 1. Do the math. Whether the scale is from -32k to +32k or from 1 to 64k, or whatever reference is chosen doesn't change this.

Using any suitable solution. Using waveguides, arrays of drivers, whatever solution takes your fancy and delivers the required result.

Again, speculative. Where have you seen a speaker that's significantly directional at primary room modes and suitable for domestic use?

One example how it COULD be done is B&O Beolab 90:

Bang & Olufsen BeoLab 90 loudspeaker

At 130+ kg and $100+k, it hardly qualifies as a speaker "that can be easily placed in normal living environments".
An interesting technical tour de force, but it does not dispense it of an integrated room correction package.

An alternative would be for example one of my custom projects that combined a sealed 12" Woofer in a concrete pipe pointing upwards and a dipole 12" placed perpendicular with independent DSP and Amplifiers to create a controlled directivity LF system

How will you prevent soundwaves to bounce on walls, ceiling and floor? That is the main reason why acoustic treatment is applied.
Do we have a chance to actually hear such a system? You claim having made, designed or projected many extraordinary things, but some kind of tangible proof would bring some credibility.

Really? Which ones?

See my other posts.

So you mean LR4 is a band aid for challenged speakers that have too narrow bandwidth?

Any x-over is a band aid for speakers that cannot properly reproduce the whole audio range, which, I think, is the case of all loudspeakers I know. Don't mention Supravox.

Where these tests conducted under conditions where you used two identical wideband drivers that would normally be used without crossovers where used as sound sources (to make sure you are literally comparing the crossover) or alternatively was the crossover output summed (without drivers) and then reproduced by a single wideband driver?

I don't really understand what you suggest, but the thing is that digital x-overs allow almost instant comparison of several types of x-over transfer functions, the rest of the system staying the same (3-way+subs), which is the essence of scientific experimentation, change only one parameter at a time.
We had a large choice of B'worth, Bessel, Linkwitz-Riley, we even tried the Hardman types (elliptic) and the Linear Phase (meh).
We also tested the LR8, which didn't give significant advantages over the LR4.
Now, it has long since demonstrated (again by Lipshitz & Vanderkooy) that between a B'worth and an LR, the difference is just one or two biquads away, so, considering all systems need some kind of EQ, it is quite possible that a B'worth4 and an LR4, with adapted EQ would result in the very same response. But a B'worth 3 will not compare to an LR4.

 

[Newmarket]

You are mistaken. What the ear perceives is the difference between the highest and the lowest pressure, around a reference which is the athmospheric pressure. The pressure "swing" is 64k, and the minimum valid swing is 1. Do the math. Whether the scale is from -32k to +32k or from 1 to 64k, or whatever reference is chosen doesn't change this.

I've actually forgotten what you are (both) trying to define here. Sounds like you are discussing different things ? Signal Amplitude ? Dynamic Range ?

At 130+ kg and $100+k, it hardly qualifies as a speaker "that can be easily placed in normal living environments".

There is that

How will you prevent soundwaves to bounce on walls, ceiling and floor? That is the main reason why acoustic treatment is applied.

+1. This was what I meant wrt room acoustic environment. Rather than loudspeaker dispersal characteristics.
Okay, to a degree you can steer the direct sound to avoid floors, ceilings. But nothing in the speaker is going to stop the soundwave going past my head and reflecting off a hard wall behind my sofa in a small living room

 

[abbey road d enfer]

So a cable with resistance, inductance and capacitance is an "electronic apparatus" , BUT ONLY if these elements are added and NOT if these elements are inherent to the cable?
How does one differ fundamentally from the other?

There are some parts of a mains cord that are fundamentally indispensable, namely conductors, insulation and connectors. Anything that's added to it makes it an apparatus, even the mundane ferrite choke. Not mentioning the decorative BS Monster wants us to believe has some functional value.

Ahh, we have reached the point to accept that we are dealing with a system.

That was my position right from the beginning.

And you suggest that all well designed systems lack any intrinsic limitations and that any systems with intrinsic limitations are poor (or cost constrained) designs?

Not at all. I suggest you re-read my posts. I wrote all systems are flawed, or something of that essence. How we accept to live with these flaws or fix them is a compromise.

A review of the "active SMPS & RF noise killer" tech in a stand alone plugin device is here:

Very audible changes are evident that can be heard even in a youtube video.

I agree that the improvement is obvious, but, although it could probably be integrated in a mains cord, it wouldn't be just a mains cord, but an appartus.

 

[thor.zmt]

You are mistaken. What the ear perceives is the difference between the highest and the lowest pressure, around a reference which is the athmospheric pressure. The pressure "swing" is 64k, and the minimum valid swing is 1. Do the math. Whether the scale is from -32k to +32k or from 1 to 64k, or whatever reference is chosen doesn't change this.

That is not how we measure SNR.

But if you insist, please encode a -96dB sinewave at 1kHz into 16Bit PCM, no DC offset, no dither.

Then after having failed, encode the smallest signal that you can actually represent.

Case closed.

Again, speculative. Where have you seen a speaker that's significantly directional at primary room modes and suitable for domestic use?

MEG RL901k.

Kii III

Shivaudio Cardioid Studio Monitor (From Romania)

Quad ESL

Dutch & Dutch 8C

At 130+ kg and $100+k, it hardly qualifies as a speaker "that can be easily placed in normal living environments".

It is a technology demonstrator.

Plus, if you call that expensive and not suited for normal living environments I would consider that your poverty is severe. It would look swell in my living area.

An 18 Channel DSP and 18-Channel stereo digital input Amplifier system (20W PCh) can be realised for around 70 USD BOM. That is for a stereo pair.

Drivers in (say) 3" for mid/hi and 5" for LF are inexpensive in volume, especially if we mold the case with the frame molded in and add magnets and voice-coil/diaphragm to this.

Yes, nobody has seen it desirable to develop such a system, but is not due to feasibility or even market potential, but down to the fact that 99% of anything consumer that is sold these days is OEM/ODM in china with no actual development being done, but everyone copying everything.

How will you prevent soundwaves to bounce on walls, ceiling and floor? That is the main reason why acoustic treatment is applied.

We need to consider what we require to allow the listener to hear the recording, not the room. We do not need to boost direct sound a lot compared to the room reverbrant field for it to dominate what is heard.

Floor, ceiling and early reflections from sidewalls can be dealt with using correct directivity. We can reduce the reflected sound from these substantially in SPL, promoting direct sound.

The wall behind the listener will reflect sound it receives, as this will be comparably directional, the majority of the sound will be reflected towards the sidewall, from where it is reflected toward the front wall between the speakers from where in turn it is reflected towards the correct sidewall, from where it will reach the listener substantially attenuated, diffused and delayed. As a result it doesn't audibly interfere with the direct sound.

Do we have a chance to actually hear such a system?

Absolutely.

If you would actually keep up with the state of the art, you would know several such systems that are easily auditioned.

You claim having made, designed or projected many extraordinary things, but some kind of tangible proof would bring some credibility.

Many of the more interesting items ended up as prototypes and were not put into production. Others were custom one offs. I do not intend to provide advertising for products I designed here.

Something interesting that is quite unusual and should interest you is this:

iFi Aurora Review: This Modern Art Piece Is Also A Killer Wireless Audio System





It can be auditioned last I looked at Harrods among others.

Note I do not endorse the product or the company, but it is something I have designed that made it into mass production.

Any x-over is a band aid for speakers that cannot properly reproduce the whole audio range,

Do you have any of them at hand?

I don't really understand what you suggest, but the thing is that digital x-overs allow almost instant comparison of several types of x-over transfer functions, the rest of the system staying the same (3-way+subs), which is the essence of scientific experimentation, change only one parameter at a time.

Yes, however you are not just testing the crossover in isolation. You are testing the crossover in conjunction with drivers.

Sum the signal back after the crossover. Any difference will be solely down to the crossover, no other interactions.

Using a high grade planar or electrostatic headphone for listening is recommended. Few speakers exist that are sufficiently full range and phase coherent to allow this test to be valid. Quag ESL may qualify in a well arranged room.

And if you find that LR4 is preferrable to BW3 in a specific system, why not try an EL10 as further option?

We had a large choice of B'worth, Bessel, Linkwitz-Riley, we even tried the Hardman types (elliptic) and the Linear Phase (meh).

Hardman does not seem to offer very steep slopes. In fact, it may be worse than LR4 and definitely worse than BW5.

Try a variation that produces a slope more like this:



In the actual crossover region it is a 60dB/8ve slope.

This is incidentally from a passive 2-Way speaker realised as passive LRC circuit driving real drivers.

The Speaker sold out a 500 Pair run, not bad for something that at the end sold at 20k per pair for a standmount.

HiFi+: LS-77 Review

But a B'worth 3 will not compare to an LR4.

No, you are right. Utterly incomparable

In a direct comparison of the crossover only, in isolation BW3 is least objectionable and the one that has the least audibility, compared to LR2, LR4, LR8, with LR4/8 being classed as seriously objectionable.

BTW, if you want a bit of background what I did and developed before taking a long break and semi-retiring in South East Asia by the beach, following a massive burnout, read here:

The Show Must Go On

Thor

 

[scott2000]

Yup, however there is a strong undercurrent among the more objectivist minded in audio that "audio is a mature technology" and that "anything that matter is measured" and the corollary "because it is measured it always matters" which mitigates strongly against any risk of ever devising new expanded measurements that would finally show a reliable correlation with perceived sound quality.

Thor

but.....but the null test ... are you calling bs?...ns?

 

[thor.zmt]

but.....but the null test ... are you calling bs?...ns?

What null test?

What are you nulling? The air pressure variations at the ear?

Any test should be controlled, first snd foremost for it's ability to demonstrate known phenomenae, secondly for bias not just in a very sense, but globally.

Are the statistics used biased? Does the test REALLY guard against bias by the subject (including placebo/nocebo).

Most of what I have seen promoted as "scientist" listening tests is the rankest and most ridiculous cargo cult "science" possible.

Thor

 

[scott2000]

Most of what I have seen promoted as "scientist" listening tests is the rankest and most ridiculous cargo cult "science" possible.

Thor

"if you don't stand for something, you'll fall for anything"

so landed on our feet...lol

 

[sahib]

This USUALLY is not relevant in our context, it is external to the network formed by audio devices, mains cables and and other interconnection cables.

Really?

Is it not the purpose of the earth to provide low impedance path to external noise currents?

In terms of your diagram, will low impedance (thicker) earth wire not allow the hum/noise currents to circulate between the two devices even easier?

 

[thor.zmt]

I've actually forgotten what you are (both) trying to define here. Sounds like you are discussing different things ? Signal Amplitude ? Dynamic Range ?

Abbey takes objection to my assertion that, once we correctly normalise 16 bit PCM to be actually comparable with analogue systems such as LP (the specific example I used) and magnetic tape, the supposed "96dB" dynamic range of 16 Bit PCM is revealed to be 76dB (theoretically 78dB) and has much less advantage over classic analogue systems than commonly claimed.

Okay, to a degree you can steer the direct sound to avoid floors, ceilings.

And this will the ratio of direct sound vs reflected sound, agreed?

But nothing in the speaker is going to stop the soundwave going past my head and reflecting off a hard wall behind my sofa in a small living room

Correct, the immediate reflection that passes your head will be integrated in the HAAS Window, so we can ignore that.

Let us assume first a hypercardiod pattern, with the acoustic axis oriented to cross notably in front of the listener.

This means a centered listener will actually listen "off axis" and as the listener moves laterally towards a given speaker, this speaker will become actually quieter and the one the listener moves away from will become louder. At least over a reasonably wide window that reaches nearly the lateral distance between speakers.

This is usually achieved with a 60 degree or so dispersion and a 45 degree "toe in" with a standard equilateral triangle placement of speakers and listener.

The sound hitting the wall behind the centered listener will actually have most of the sound impacting significantly to the left and right of the listener, before being reflected away from the listener towards the side wall opposite from the speaker.

The sound will naturally reflect with a certain degree of diffusion, which will reduce intensity both by path length and by spreading the sound intensity across a larger area.

From the sidewall, the majority of the sound will be reflected to the wall behind the speakers, from where it will be reflected to the sidewall next to the speaker that originated it, attenuated, diffused and with a significant accumulated delay, usually sufficient to avoid the HAAS Window, and thus avoiding tonal changes, but instead being perceived as low level delay/reverberation.

Is it perfect? No.

Is it a major improvement over any old monkey coffin (never mind B*se 901 or Omni's)? Hell yeah.

Thor

 

[thor.zmt]

There are some parts of a mains cord that are fundamentally indispensable, namely conductors, insulation and connectors. Anything that's added to it makes it an apparatus, even the mundane ferrite choke.

I take a different position. The mains cable, because in a real cable it ALWAYS has R, C, L, G and antennae action, it is " an Apparatus" in our definition, or rather something of which the systemic needs to be evaluated and cannot be automatically assumed to be "zero".

And different construction of cables including items that do not directly alter measurable RLC can have quantifiable effects on some areas of the behaviour of the "non apparatus", that is in fact an apparatus in all relevant definitions of the term, if we posit that for example a RLC Filter is classed as "apparatus".

Not mentioning the decorative BS Monster wants us to believe has some functional value.

Now we get down to the nitty gritty. You take this position because you perceive (rightly or not is beyond this discussion) fome feature of a commercial product that is heavily marketed as BS and it cannot possibly allowed to give any definition that would in any way possibly give any remote validation.

In other words, it doesn't matter to you what's right or wrong, but who (or more precisely that your interpretation is perceived as "right", disregarding even the possibility alternative viewpoints may hold validity. Please read your own signature and then re-evaluate your position in this argument against facts.

I agree that the improvement is obvious, but, although it could probably be integrated in a mains cord, it wouldn't be just a mains cord, but an appartus.

But a mains cable is an RLC filter, so it is an apparatus anyway. Adding a few bux of electronics to make it a more complex apparatus do not change it's status.

Thor

 

[abbey road d enfer]

That is not how we measure SNR.

Signal -to-noise ratio is a figure of merit that sometimes allows comparison, but it actually pertains to a notion of power.
Your reasoning is that teh amplitude is limited to 32k because that's what it appears when dealing with power, but the pressure perception doesn't work with power, it relates to the absolute value of teh pressure swing.

But if you insist, please encode a -96dB sinewave at 1kHz into 16Bit PCM, no DC offset, no dither.

You know well that the numerous imperfections in the system would end in results that are notably poorer than the mathematical expectations.

MEG RL901k.

Kii III

Shivaudio Cardioid Studio Monitor (From Romania)

Quad ESL

You can't be serious...

Plus, if you call that expensive and not suited for normal living environments I would consider that your poverty is severe. It would look swell in my living area.

I noticed you are very proud of your wealth

We need to consider what we require to allow the listener to hear the recording, not the room. We do not need to boost direct sound a lot compared to the room reverbrant field for it to dominate what is heard.

Reverberant field is one thing. Emphasis/attenuation of eigentones is another. Although teh linear-phase portion can be EQ'd, tehre is still something that cannot be solved electronically. Attemps to use active slapback cancellation have never been met with success.

Do you have any of them at hand?

What do you mean? Of course I have (or rather had because I'm not anymore active) many loudspeakers that had limited usable frequency response.
Subwoofers that go up to <100Hz, woofers that go from 50 to 3k, midrance that go from 300 to 5k, and HF drivers that start at 2k.

es, however you are not just testing the crossover in isolation. You are testing the crossover in conjunction with drivers.

What do you mean? How can you test a x-over without speakers? You can measure a x-over, but it won't tell you which one sounds good and which one bad.

Sum the signal back after the crossover. Any difference will be solely down to the crossover, no other interactions.

Using a high grade planar or electrostatic headphone for listening is recommended. Few speakers exist that are sufficiently full range and phase coherent to allow this test to be valid. Quag ESL may qualify in a well arranged room.

You remind me of a customer that goes to a show and asks for listening to a specific pair of loudspeakers. The Salesman says :" I'm sorry sir, this is a silent show, but if you want I can make you listen to them on headphones".