Harrison Labs In-line Crossover Review (RCA)

[Doodski]

So is it fair to say in simpler terms that the resistor value essentially acts as a valve that controls the charge/discharge rate of the capacitor

Yes, that's happening.

With 1 Tau = the resistance (in Ohms) multiplied by the capacitance (in Farad) = 1 tau (in seconds)
So to reduce one or the other results in reduced time or a smaller Tau quantity (in seconds).

without it (The resister) the cap would essentially be at full charge consistently and would no longer serve to shunt off the high frequencies? Be kind please, was not taught this in med school…

In order for the cap to perform it must have a changing voltage across it's terminals. If there is DC then there will be nothing happening other than charging to 5 Tau really fast.

 

[aerochrome2]

Purely anecdotally, since this is room dependent, high passing my mains with the 100hz hp FMOD really flattened a couple of peaks and nulls I had sub 150hz.

(I actually just ordered the XLR version today since I changed amps and now only have XLR inputs on my amp.)

 

[Oski1928]

I’ve looked into these before but was skeptical that they would in some way degrade the signal. I don’t know much about this stuff so I’m looking for help. I’m running a 2.0 setup and my speakers extend to about 34hz in my room. I’d like to get rid of what’s below that for both the speakers and the amp (which I think will be beneficial especially when watching movies). The only option I see that kind of makes sense is the high pass filter at 50hz 12db/octave. My concern is that this will eliminate too much of the bass below 50hz that my speakers do play. Is this a correct assumption? I would be connecting these in between my streamer and my integrated amp, will this be okay as well?

I’ll also add that I’ve seen a lot about how the impedance of the amp matters and I don’t know much about that either, so would this be okay for my amp? According to the specs the input impedance for the line in on the amp is: 220 mV/13 kΩ/kohms.

 

[EJ3]

In my opinion it might be enough with a 12 dB/oct low pass filter if you use two subwoofers very close to each ( inverted) main loudspeaker, in stereo . No need to always try to get 24 or 36 dB/oct crossovers lowpass filtering. It depends on many things.

One example: The REL subs always uses 12 dB/oct (inverted phase) LP and thats one of the reasons they integrate well with unfiltered closed box main loudspeakers, because they drop off naturally with 12 dB/oct below box resonance.

Using only one subwoofer, ( which is bad for sound ) theres often a need for a steep filter, 36 dB/oct LP, or even more.
And then you also need a steep high pass crossover.

what about sub woofers that are aimed at the floor? (mine are)

 

[AL B BACH]

My concern is that this will eliminate too much of the bass below 50hz that my speakers do play. Is this a correct assumption?

They make 30Hz and 20Hz versions you could try out. Available from Amazon or Parts Express.

https://www.amazon.com/Harrison-Labs-Inline-Subsonic-Crossover/dp/B00S8XXYHC/ref=pd_lpo_3?pd_rd_w=KYono&content-id=amzn1.sym.116f529c-aa4d-4763-b2b6-4d614ec7dc00&pf_rd_p=116f529c-aa4d-4763-b2b6-4d614ec7dc00&pf_rd_r=JNSETMHBBZVBD192TVBT&pd_rd_wg=ZYNqF&pd_rd_r=6baaff74-badb-4046-a5e0-d6eff9c704f6&pd_rd_i=B00S8XXYHC&psc=1

 

[DonH56]

I’ve looked into these before but was skeptical that they would in some way degrade the signal. I don’t know much about this stuff so I’m looking for help. I’m running a 2.0 setup and my speakers extend to about 34hz in my room. I’d like to get rid of what’s below that for both the speakers and the amp (which I think will be beneficial especially when watching movies). The only option I see that kind of makes sense is the high pass filter at 50hz 12db/octave. My concern is that this will eliminate too much of the bass below 50hz that my speakers do play. Is this a correct assumption? I would be connecting these in between my streamer and my integrated amp, will this be okay as well?

They should not degrade in any meaningful way. They are passive filters so any added noise or distortion is negligible.

I’ll also add that I’ve seen a lot about how the impedance of the amp matters and I don’t know much about that either, so would this be okay for my amp? According to the specs the input impedance for the line in on the amp is: 220 mV/13 kΩ/kohms.

There is info on the Harrison Labs website: https://www.hlabs.com/products/crossovers/index.htm -- key specs listed below.

There is some dependence upon driving and load impedance but the exact frequencies are rarely too critical.

HTH - Don

From the website:

SPECIFICATIONS
GOLD OVER MACHINED BRASS
RCA JACKS 0.4” O.D. X 2” LONG

20 VOLTS RMS MAXIMUM
STD. DRIVING IMPEDANCE 600Ω

MAXIMUM DRIVING IMPEDANCE 10,000Ω (10KΩ)

NOISE AND DISTORTION TOO LOW TO MEASURE

ACCURACY ± 1% @ 22KΩ LOAD

The color ring indicates Hlabs standard crossover frequency (-3db point)
There is an 8%(LP) / 25%(HP) frequency increase at 10K ohms and 8%(LP) / 15%(HP) frequency decrease at 47K ohm load. Otherwise all color design values of crossover frequencies are standardized at 22k ohms. Keep in mind that exact crossover frequencies are seldom noticed or necessary.

20hz black bands (25hz @ 10K / 17hz @ 47K)
30hz 2 black bands (37hz @ 10K / 26hz @ 47K)
50hz brown band (54hz @ 10K / 46hz @ 47K) (62hz @ 10K / 43hz @ 47K)
70hz purple band (76hz @ 10K / 65hz @ 47K) (87hz @ 10K / 60hz @ 47K)
100hz has no band (108hz @ 10K / 92hz @ 47K) (125hz @ 10K / 85hz @ 47K)
150hz 2 blue bands (162hz @ 10K / 138hz @ 47K) (187hz @ 10K / 128hz @ 47K)
200hz blue band (216hz @ 10K / 184hz @ 47K) (250hz @ 10K / 170hz @ 47K)
300hz 2 white bands (375hz @ 10K / 255hz @ 47K)
500hz white band (540hz @ 10K / 460hz @ 47K) (625hz @ 10K / 425hz @ 47K)
1000hz light blue band (1080hz @ 10K / 920hz @ 47K) (1250hz @ 10K / 850hz @ 47K)
2500hz light green band (2700hz @ 10K / 2300hz @ 47K) (3125hz @ 10K / 2125hz @ 47K)
3500hz gray band (3780hz @ 10K / 3220hz @ 47K) (4375hz @ 10K / 2975hz @ 47K)
6500hz orange band (7020hz @ 10K / 5980hz @ 47K) (8125hz @ 10K / 5525hz @ 47K)

 

[RWL2023]

Is there any FMOD that will work in reverse, adapted to 3.5mm jacks for a microphone (that has plug-in power, if that's relevant)? I've got an on-camera microphone that I want to put a HPF on, something like 60-80Hz. I've contacted the manufacturer for the impedance rating, as for some reason it isn't published.

 

[DonH56]

Is there any FMOD that will work in reverse, adapted to 3.5mm jacks for a microphone (that has plug-in power, if that's relevant)? I've got an on-camera microphone that I want to put a HPF on, something like 60-80Hz. I've contacted the manufacturer for the impedance rating, as for some reason it isn't published.

Impedance is definitely a concern, but a HPF usually includes a series capacitor that will block DC (phantom power) from the mic so this probably would not work.

 

[newaudioguy]

When it says "20 VOLTS RMS MAXIMUM" what is that in wattage?

 

[DonH56]

When it says "20 VOLTS RMS MAXIMUM" what is that in wattage?

These are line (low) level filter components so power is not usually a concern and is not specified AFAIK. The voltage rating is probably related to the capacitors used in the filters. The actual power through the filter depends upon the driving and load impedances, since that determines the maximum current through the filter, and the unknown (or at least unspecified) internal resistance.

These are not for speaker use.

 

[fpitas]

What DonH56 said. These are for line-level signals.

 

[Ron Texas]

These are particularly useful as high pass filters on the mains when subwoofers are used. Usually the sub has it's own low pass filter. 12 dB/Octave @ 100Hz will do the job in many systems. This will allow increased dynamic range especially with bookshelf speakers.

 

[fpitas]

My only problem using these, and it's not inherently their fault, is that there is no adjustment for phase or delay.

 

[newaudioguy]

Ah you are correct this should connect between source and power amp. I might get the <100hz lpf to use from my A300 to a CVR802 sub poweramp that lacks any filters or equipment.

 

[dlaloum]

My only problem using these, and it's not inherently their fault, is that there is no adjustment for phase or delay.

They are minimum phase - if you adjust your frequency response / EQ using Minimum phase filters, the end result will be neutral frequency AND phase.

 

[fpitas]

They are minimum phase - if you adjust your frequency response / EQ using Minimum phase filters, the end result will be neutral frequency AND phase.

Sure, if everything else conveniently lines up in phase. It seldom will.

 

[dlaloum]

Sure, if everything thing else conveniently lines up in phase. It seldom will.

As long as the things that are altering phase are minimum phase (most natural phenomena are!) - then phase and frequency are symmetrical - get one neutral and the other will be too.

 

[fpitas]

As long as the things that are altering phase are minimum phase (most natural phenomena are!) - then phase and frequency are symmetrical - get one neutral and the other will be too.

You mean a sub across the room will be right in phase with the main speakers? I'm very skeptical.

 

[DonH56]

As long as the things that are altering phase are minimum phase (most natural phenomena are!) - then phase and frequency are symmetrical - get one neutral and the other will be too.

What @fpitas said -- the problem is subs tend to be physically away from the mains so you need extra delay someplace... For my first sub, a DIY servo job with active electronics, I incorporated an all-pass filter to adjust the phase to the mains.

 

[EJ3]

What @fpitas said -- the problem is subs tend to be physically away from the mains so you need extra delay someplace... For my first sub, a DIY servo job with active electronics, I incorporated an all-pass filter to adjust the phase to the mains.

For about 10 years I have been using these on my pair of Radio Shack floor firing SUB Cabs, (the larger of the 2 subs that they built, black in color), each fitted with a 12" Pioneer dual 4 Ohm voice coil (circuit set up to be seen as a single 4Ohm circuit) car audio speaker that has a 20Hz-80Hz FR. My mains are 26Hz-20KHz +-2DB (Dahlquist M-905's). They sit on top (so phase is not an issue (the room is not symmetrical so the subs do not see the same thing as far as standing nulls are concerned) of the SUB's. Each sub has one bridged mono NAD 2200 amp and the mains have a NAD 2200 in stereo.

[IMG alt="Text Box: LP1 FOR WOOFER AND SUB-WOOFER AMPLIFIERS #900091
42, 44, 46, 48, 50, 52, 55, 58, 65, 70, 80, 85, 100, 120, 150, 200 HZ LOW PASS

NEW! HP-SUB ADJUSTABLE SUB-SONIC FILTER
20, 25, 30, & 35HZ HIGH PASS FILTER (Blocks Rumble)
HP1 FOR MIDRANGE AND TWEETER AMPLIFIERS #900101
50, 70, 100, 150HZ HIGH PASS CROSS-OVER

2W1 FOR 2 WAY SYSTEMS #900121
50, 70, 100, 150HZ HIGH PASS AND 42, 44, 46, 48, 50, 52, 55, 58, 65, 70, 80, 85, 100, 120, 150, 200 HZ LOW PASS
HIGH AND LOW PASS CAN BE SET TO DIFFERENT FREQUENCIES
"]https://www.hlabs.com/products/crossovers/index_files/image800.png[/IMG]

[IMG alt="Text Box: FOR HOME OR AUTO USE/
REQUIRES NO DC POWER OR POWER WIRING
18 DB/ OCTAVE LOW PASS / 12 DB/ OCTAVE HIGH PASS (subsonic)
ADDS VIRTUALLY NO NOISE OR DISTORTION
"]https://www.hlabs.com/products/crossovers/index_files/image765.png[/IMG]

)