Cable with one direction

[Bob from Florida]

But you still get ground loops from the twisted pair ground. And the shield is still conected to both grounds thru the twisted pair. And the best cable for unbalanced is still coax, which that is not.

That's not how you get ground loops. If your unbalanced "ground" wire is connected to chassis ground which is in turn connected to a power cord ground wire in 2 or more pieces of gear that all have grounded power cords - then you have potential for ground loops due to the power cord grounds. Double insulated gear without earth grounded power cords perform best with unbalanced connections between gear.

 

[Chrispy]

I traded a few things with a friend this weekend. He had cables that seemed to be well shielded so I took them. I thought it wouldn't hurt to have better shielded RCA cables than what I have now. I have no problem with my cables picking up noise, but you know, HiFi neurosis can crept in. Best to be on the safe side just in case and so on.

To the topic of the thread! On the cable it says: High End PLUS High Resolution Interconnect Cable UPOCC
May be as it is with it but after where it says UPOCC there are three arrows, see picture. I'm guessing that these arrows are supposed to show how to connect the cables from the signal source to the amplifier to get the best sound?
I thought that was a bit funny. I never cease to be amazed by this weird Hifi world. For quirky in cubic, you should of course check out what is considered "High End". There are, as you know, big gold mines of weirdness.
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I don't know the brand of the cable.

Right now I only have those blue cables, so suggestions for good, sensible RCA connectors are welcome. RCA connectors that are easy to work with, i.e. are well constructed that make it easy to solder cables to them, please let me know.

Just what are you connecting particularly? Maybe you have something in need of a specific "directional" cable but....

 

[antcollinet]

That's not how you get ground loops. If your unbalanced "ground" wire is connected to chassis ground which is in turn connected to a power cord ground wire in 2 or more pieces of gear that all have grounded power cords - then you have potential for ground loops due to the power cord grounds. Double insulated gear without earth grounded power cords perform best with unbalanced connections between gear.

Even so - there is no difference for ground loops between twisted pair with a sheild connected only at one and, and a coax cable.

In both cases pin is connected to pin, and ring to ring in the RCA interconnect. If there is potential for ground loops between the two devices, disconnecting the shield at one end but with the ring still connected by one connector of the twisted pair doesn't alter that.

And you can still get ground loops even with double insulated devices. Loop via mains is one form, but it is also possible to create a loop purely via interconnect. Also by connecting to another device further down the chain which is grounded.

 

[MaxwellsEq]

In an alternating current, the electrons move in one direction then back again. I wonder if my house mains wiring has most of the original electrons still in it. Good thing electric companies don't make us pay for electrons delivered.

 

[Bob from Florida]

And you can still get ground loops even with double insulated devices. Loop via mains is one form, but it is also possible to create a loop purely via interconnect. Also by connecting to another device further down the chain which is grounded.

Really, a ground loop without a loop? You have to have at least 2 grounded devices for the loop to form. Unless you are adding mains frequency coupling to the interconnect via electromagnetic means due to interconnect relative position to a radiating source. But that is not a "ground loop". Here is a link for pro's and con's of twisted pair and coax. https://www.geeksforgeeks.org/difference-between-coaxial-cable-and-twisted-pair-cable/
For audio bandwidth and typical interconnect distances both types work fine.

 

[Bob from Florida]

In an alternating current, the electrons move in one direction then back again. I wonder if my house mains wiring has most of the original electrons still in it. Good thing electric companies don't make us pay for electrons delivered.

Exactly, and ultimately was the reason Tesla won the battle of AC vs DC power distribution with Edison.

 

[Berwhale]

Exactly, and ultimately was the reason Tesla won the battle of AC vs DC power distribution with Edison.

But with Edison's scheme we would have had a steady stream of shiny new electrons to feed our gear with! Instead, we end up constantly recycling the same set of dirty electrons - they only move 60th/50th of a millimetre before changing direction - it's no wonder my system sounds muddy

 

[antcollinet]

Really, a ground loop without a loop?

Ground doesn't have to be mains ground. It can be analogue signal ground.

Imagine two ungrounded (mains ground) devices. One is a recording device (say an audio interface connected to a laptop). The other is an integrated amplifier with record output.

You have RCA from the ouput of the interface into the Amp. You have RCA back from the record output of the amp back to the interface. You might have other devices feeding the amp. You now have a ground loop in the analogue interconnect - ie the (analogue audio ground) from the interface, to the amp via one set of RCA and back from the amp to the inteface via the other RCA pair. Any magnetic field that passes through that loop will induce currents in that loop.

And as you rightly point out, put a device with a powerful mains transformer in the vicinity of that loop and. you can very easily induce audible mains frequency hum in that loop. (do not ask me how I know this)

Similar loops can be created between an AVR and TV/other connected devices for example between the HDMI lead, and any audio path back to the AVR, such as another device connected to both the TV and AVR. In fact any system that doesn't have a linear one way single interconnect system from source to amp.

 

[DanielT]

Both of these drivers look fairly well-behaved and actually are of almost the same sensitivity. All hell breaks loose in the woofer above 5.5 kHz though, so you will definitely need at least one rather broad notch for that one. (Low Q is good for you, it means you need a relatively low inductance only, so small series resistance.) The area around 10 kHz is particularly critical.

I wouldn't see a problem with pushing the crossover to 2.0 kHz, the tweeter can definitely take it, especially in combination with this relatively weak midwoofer. I've seen speaker measurements indicating tweeters outclassing their woofers so many times I've lost count. If you want to add some extra passive highpass filtering like a series capacitor to better address the area <1 kHz, I would want to linearize the impedance (flatten out the resonance hump) first. The good thing about an active crossover is that it isn't affected by varying driver impedance.

Of course you can use a normal excursion 5" woofer to 100 Hz. Yes, this one is ideally crossed over at 200 Hz for best level handling, but in practice more typical sub crossovers of 100-150 Hz should be just fine.

Do note that you will have a timing alignment problem simply due to geometry if you put both on a flat baffle. The woofer's effective sound origin is going to be further back than the tweeter's. Making the baffle slanted would be one way to address this issue. If that should turn the affair into a woodworking nightmare, angle the entire speaker up as required and optimize it like that, I can't imagine you need more than 5-10°. That's where a digital crossover could just dial in a bit of delay for the tweeter instead.

On a related note, make sure the woofer and tweeter are properly inset into the baffle and come out flush. (You can do some modelling with an epoxy / wood pulp mix or something along those lines if required.) Also, the "suitable" c-c distance is likely to be the minimum feasible one, given how wide the tweeter's mounting ring is to begin with. (When both are just touching each other, c-c is 75 + 50 mm = 12.5 cm. Sound wavelength even at 2 kHz is only about 17 cm, and ideally you'd want to be under half that, i.e. 8.5 cm.) Some manufacturers of nearfields even trim off something, or some like Dynaudio go the cheap route of mounting the woofer on top of the baffle so they can overlap (see e.g. LYD 5 or BM5 MkIII)... the downside being that the tweeter "sees" a step from the outer ring (followed by the surround), which creates diffraction and disturbs dispersion. There's a reason why all the best speaker designs have super smooth-looking baffles. You can try to "hide" the woofer by modelling something around it à la Neumann and others. A lot of nearfields also have the woofers slightly inset into the baffle, even cheap ones... have a look at the things you find on Thomann or something. Even a lot of the cheap 3"-4" class wannabe monitor sets with their crappy single-capacitor crossovers have super advanced baffle designs.

Interesting aspects you bring up. I will think about them when I sketch my design.

What you point out is what I was thinking about, i.e. the bass woofer break up above 5.5 kHz and how it can be filed down. Notch filter can absolutely be a solution, if not a 24 dB filter is not enough to get it inaudible.

The baffle will have substantially rounded corners, flush mounted drivers. Possibly the speaker it will be with a waveguided tweeter just as McFly did with the same SB drivers that I have:

Revel M105 Copy DIY build

After seeing the success of Directiva, But knowing the price, I wanted a nice small pair of passive bookshelf speakers for use in the second living room. I didn't need massive SPLs (if you need more SPLs the Directiva is much better - however that build is DSP XO + Multi Channel amplified). The...

audiosciencereview.com

Kimmosto (creator of VituixCad) , about c-c distance said something interesting. Page 1,#2:

Minimum c-c is 1.0 x wave length and maximum about 1.4 x wave length at XO frequency assuming that design is conventional uni-directional box (not open baffle) with phase matching (acoustical 4th order) slopes. Good and quite flexible initial/design value for c-c is 1.2 x wave length at XO, giving smooth combination of power and early reflections i.e. balanced sound without significant power dip at XO due to bump in DI and dip in vertical early reflections. In other words, this concept aims lobe nulls to directions which are the least significant for power response and vertical early reflections - and listener sitting in sweet spot of course.

Some help with lobing

I think I understand the concept but can't figure out the solution. "Lobing occurs with any two drivers producing the same frequency range in parallel (identical signal) where the distance between the drivers is greater than 1/4 wavelength of any frequency they are reproducing." So if I am...

audiosciencereview.com

I'll get back to my speaker project in another thread once I get it going.

 

[DanielT]

Just what are you connecting particularly? Maybe you have something in need of a specific "directional" cable but....

In my #6 you see what I intend to connect.

 

[Chrispy]

In my #6 you see what I intend to connect.

Why is the crossover not before the subs? The intended gear doesn't really tell me a lot about the why, tho.

 

[jsrtheta]

Never seen Belden, Mogami of Canaree cables directional and those three brands as are used by 99% of recording studios!

I have a number of Canare interconnects, and they are all marked directional.

 

[Chrispy]

I have a number of Canare interconnects, and they are all marked directional.

Difference between a specific pre-built connector and bare cable?

 

[Descartes]

I have a number of Canare interconnects, and they are all marked directional.

Interesting all my Canare cables do not have any directions on them!!
I get them from Markertek who primarily sells to pro audio and studios.

 

[DanielT]

Why is the crossover not before the subs? The intended gear doesn't really tell me a lot about the why, tho.

That's because the speakers I'm going to build don't have a crossover, so my active crossover is needed for them.

Together with my two subwoofers, which have a built-in LP-HP filter, it then becomes a three-way solution.

 

[DanielT]

My project is going at a snail's pace. If you can even classify it as a project. It's just a matter of soldering some cables to RCA connectors. It's done in a few minutes BUT I had to have some RCA connectors.

I managed to come across a number of used WBT RCA connectors at a really good price. Good construction for soldering small cables onto them AND as a bonus you can screw that casing yourself as hard as you think is good. So it therefore squeezes as much into the RCA female as is just right, not too much or too little. It was a nice feature with those RCA connectors.