Harrison Labs In-line Crossover Review (RCA)

[amirm]

This is a review and measurements of the HLabs in-line RCA 50 Hz crossover. It was kindly sent to me by a member and costs US $27.95.

I understand these are popular with car audio folks. Company sells many variations of this and also a custom version. The sample I received was "New Old Stock" purchased by the member. Can't say I am impressed by the way it has aged given the pitted RCA female plugs. The male side uses those ultra long center pins which could cause problems for some jacks. Definitely old fashioned in this regard.

For some odd reason company claims these are "active crossover but without needing power." Well, if they don't need power then they are passive crossovers. Better said, line level crossovers.

HLabs Crossover Measurement
The only relevant test I could think of for these is a simple frequency response. Input impedance of the analyzer is 100 kHz:

Seems like there is variation in parts used (RC?) causing difference in attenuation. The nominal stated crossover value of 50 Hz is at the standard -3 dB point. Whether this slope matches your application is something only you can decide.

Conclusions
Other than the cheap build and misstated name, the Harrison Labs in-line crossover does it what it says it does.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

 

[PeteL]

For some odd reason company claims these are "active crossover but without needing power." Well, if they don't need power then they are passive crossovers. Better said, line level crossovers.

In my world I just call that a low pass filter.

 

[amirm]

Yeh, that is a more accurate name.

 

[Loathecliff]

I wonder if they do tours of their 'laboratory'

 

[Tangband]

Edit: Looks like a 12 dB/oct lowpass RC filter.
Can be interesting if you have two DIY subs that dont need eq and placed very near each of your main loudspeakers, in stereo. I have a couple of years ago tried something like this with my former DIY subs , and the listeningresult was rather good I thought.

If the main loudspeakers are closed and with no HP filter, they gonna roll off about 12/oct below the box resonance freq, thus making rather good integration with this passive line-crossover.

 

[Vladimir Filevski]

No coil inside, it is a simple RC low-pass filter.

 

[Bamboszek]

Did you performed THD measurements?
I would be interesting as capacitor in filter could be limiting factor.
They probably used some film cap but still.

 

[Tangband]

Did you performed THD measurements?
I would be interesting as capacitor in filter could be limiting factor.
They probably used some film cap but still.

The filter gonna measure like 140 dB SINAD, because its passive. No noise and probably very low distortion.

 

[muslhead]

Perfect timing. Was going to pick up a pair to use with my sub which only has lfe input and my amp which does not have sub out to see if it worked
Thanks Amir

 

[tifune]

I use some of these in the absence of a digital crossover. Having only ever used digital crossovers, the slope options struck me as unusual but maybe that's normal for passive crossovers? they have a "tutorial" on their site about how to combine their attenuators & corssovers to compensate but these are a little pricey for what they do, so you rapidly approach the cost of a cheap digital crossover if you need to buy 2+ and an attenuator for a more "modern" slope.

As an aside, I emailed their support for 1-2 clarifications and they were friendly enough but signed the email with a few youtube URLs and description: [BTW, here's a few links revealing COVID as a hoax and how *you can fight back!*] I forget exact wording, but that was definitely the gist. I thought that was a bit forward, but hey it's their operation. Power to the people, freedom of speech, etc etc (I guess?) - similar material still on their site, it seems.

 

[DHT 845]

Nice solution in bi-apmling especially with powerful preamp with possible 2 simultaneous outputs like topping Pre90.

 

[tifune]

Nice solution in bi-apmling especially with powerful preamp with possible 2 simultaneous outputs like topping Pre90.

Wouldn't that result in different gain since the outputs run at different voltages?

 

[solderdude]

Whether this slope matches your application is something only you can decide.

They also sell a 50 Hz (12dB/oct) high pass. That should work well providing both speakers extend beyond 50Hz.
These are also available in many other frequencies and in XLR versions.
Here is a related thread

 

[Bamboszek]

The filter gonna measure like 140 dB SINAD, because its passive. No noise and probably very low distortion.

That is not true. To reach 140 dB THD+N you need very careful selection of passive components.
Class II ceramic capacitors THD could be very bad, there is some difference between plastic film types too (PET vs PP etc.). Generally C0G ceramics are most linear.
Thick film or carbon compositions resistors tend to be noisy and distort too.
If it's passive it still can introduce noise. Actually resistors are main noise source in audio electronics due thermal (Johnson–Nyquist) noise. Modern opamps are less noisy than 100 ohms resistor.

So THD vs freq and THD vs voltage graphs could be interesting to see, even for passive filter.

 

[solderdude]

Besides... 1kHz is already 40dB attenuated so the noise floor of the test equipment will also be 40dB closer as the stimulus (1kHz) is attenuated.
Opposite 1kHz the harmonics only seem to be attenuated 20dB or so.
A true low pass would drop below -60dB so it looks like the used capacitors have some (intentional ?) series resistance ?
Perhaps it is closer to an extreme low-shelf than low-pass.

 

[Tangband]

That is not true. To reach 140 dB THD+N you need very careful selection of passive components.
Class II ceramic capacitors THD could be very bad, there is some difference between plastic film types too (PET vs PP etc.). Generally C0G ceramics are most linear.
Thick film or carbon compositions resistors tend to be noisy and distort too.
If it's passive it still can introduce noise. Actually resistors are main noise source in audio electronics due thermal (Johnson–Nyquist) noise. Modern opamps are less noisy than 100 ohms resistor.

So THD vs freq and THD vs voltage graphs could be interesting to see, even for passive filter.

Agree, it would be nice to see THD and noise on this unit.

 

[Madjalapeno]

Ooh, this needs a tear-down.

(Thanks for the finding weird and wonderful new things to test.)

 

[Apesbrain]

I would never knowingly purchase anything made by Harrison Labs:

 

[hollis]

…this slope…

What happens if you stack two of them? Do you get 24dB/oct?

 

[FrantzM]

Hi

It's official. Zach's Snyder, he of zombie movies' fame, is going to make a movie about @amirm . Title of the movie: He Never Sleeps.