The All Purpose Advice Thread

Not a label I've even heard of before, not encouraging in the slightest, haha. Thanks @zonto, tracked it down on Amazon. Much obliged!

 

I'm curious how cannons would sound. Will have to look into this more. My favorite genre is what some would call "concept music" - Pink Floyd, Alan Parsons, Marillion sort of stuff. And one of my fave albums is Roger Waters solo Amused to Death (it could just be another Pink Floyd album really).

There are a lot of sounds that are not really music, just sounds of life. And there is a track where people are in the streets and then a missile flies in and explodes. I've never measured it - I should - but I think that is the highest SPL my system ever hits out of anything I listen to. Makes the house shake lol.

 

I'm rather fond of atypical instruments myself. Saw this one enjoyable piece where a typewriter solo was featured a little bit ago— seemed like fun for fun's sake, almost, which I'm not personally against.

The recording I've been listening to is a Telarc release over on YouTube (shush I know the quality bites, that's why I'm asking ). I looked into it and it seems they used digital recorders for the cannon fire, which likely explains the obscene clipping. The whole song is a great listen IMO, but cannon barrage starts around 14:30 in if you're pressed for time:

I have heard actual cannons firing at a distance before, and I will say that I'm only too glad for the volume normalising wizardry here— orchestras can get loud, but that's something else entirely. I'll definitely have earplugs and pockets full of cotton along if I were to watch a live performance of this up close.

 

I'm looking into purchasing a pair of custom sleeves from Sensaphonics for a Shure UIEM, just have questions about durability.

I'd appreciate any feedback on durability from owners of the custom silicone products by Sensaphonics. I consider CIEMs to be non-consumable items, but in the past, the silicone tips on my old Etymotic er-6i UIEMs would start to loose their shape after a few months, necessitating replacement. Conversely, I've never had a problem with acrylic CIEM products from Unique Melody and Noble.

This was originally posted in the IEM equipment thread but a mod suggested reposting here. Idk, I'm new to SBAF.

 

I downloaded the HDTracks Mercury Living Presence . Really good recording especially considering it was 1955. I wonder what those engineers could do now, IF......... DR wasn’t the standard it is now. The cannons are so great. They played this version from the Big T’s original manuscript with the specified “special effects”. As close to the way he wanted to have it played as anyone has played it.

It never was played this way in his time. Budget cutbacks, and tax cuts. Worth the $ for me.

 

@Ringingears Ooh nice! So might be worth going HDTracks over CD? Surprisingly might cost more given how much used copies are online, but I'm probably willing to spend extra on tracks I really like if it's not insane, haha.

 

@Lyer25 sent a PM.

 

The label is Mercury Records, and had a major role in the history of classical and jazz recording.
https://en.wikipedia.org/wiki/Mercury_Records
The Mercury Living Presence series is very well known in classical music recordings. Its catalog includes some of the most highly regarded classical music recordings for both performance and sound, and popular with audiophiles. The Mercury Living Presence 1812 Overture by Antal Dorati is well known and became a best seller when it was released. Scroll down this page for some notes about this 1812 Overture recording:
http://www.speakerscornerrecords.com/news/details/4/mercury-living-presence-the-history

The best known newer recording of the 1812 is probably the one by Erich Kunzel and the Cincinnati Pops on Telarc Records. It became a showpiece among audiophiles, especially for its LP release which on many record players caused the stylus to jump the groove during the cannon shots.

 

I've got a question concerning XLR cables and their "capacitance" (pF).

I am not familiar with these technical issues, but read the following (translation from german):

source: https://www.amazona.de/test-cordial-xlr-mikrofonkabel/5/

I am asking because I am about to buy XLR cables for connecting Yggdrasil and Freya + for a distance of ca. 10 meters (33 feet).

My questions:

1. Has anyone experience with this issue?
2. From which cable length is this to be considered?

Thanks in advance

 

I readily admit ignorance of the history of loads of audio and recording companies, haha. I did do some quick googling after the fact, but it really is great that old, storied names like Mercury persist. Appreciate the link! Extra pasttime reading is always welcome.

Could just be because I've not heard a proper copy of the Telarc release, but that's the one I catch clipping during cannon fire on. Might be my crud rig, which I'll be a long while rejiggering.

 

Calculated it for you. In order to have a -0.3dB attenuation at 17500Hz, with Yggdrasil's 75 ohm outpt impedance, the max capacitance you can have in your cable is around 23 nF.

Here is your formula, pluck it into google

(sqrt(1/0.966051-1))/(2*pi)/17500/75

0.966051 is the -0,3 db, you can use this http://www.sengpielaudio.com/calculator-gainloss.htm - the first calculator, voltage loss in db to get this number.

17500 is the frequency "cutoff", 75 is the output impedance.

so something like

(sqrt(1/(Voltage Ratio Loss)-1))/(2*pi)/frequency/(output impedance)

 

Thanks a lot! I don't understand everything, but since 23 nF is a lot more than 55 or 95 pF that the cables have that I consider, it seems I should be safe.

But: I can't find any cable length / distance in your calculation. How come? I thought this plays a major role in this scenario?

 

It's really simple, if your cable is 1nF/m then you're good for 22m. Usually they are far less then this. Connectors contribute some too, if you are that worried grab a cheap multimeter and measure the cable yourself. So, yeah. Not that much to worry about really. Cable capacitances are usually in picofarad ranges.

 

Yep. Only really matters in practical lengths of they're after a pot or resistor ladder passive. So don't run that Freya in passive mode.

 

Yep. If running balanced, and Freya in passive mode, you have about 2800 pF max in cable capacitance to meet the former requirements. Lots less, still probably fine for short runs with ok quality cables.

 

No, wait, hmm. I just took the 600 ohm balanced impedance out. Maybe it's more in passive mode. That'd mean even less, possibly introducing problems. Perhaps someone knows exactly the size of the pot inside, in that case the output impedance would be at worst 1/4th of the max size of that pot, if my memory serves me well. Could be a lot more than 600 ohms. Best to go active, then you're fine with whatever.

This talk is ofcourse for downstream of freya. From yggdrasil to freya, as you asked, don't worry about it.

 

Not sure, it's a pcb-mounted relay-switched stepped resistor dealio, and the site only gives the outZ for the active modes, but in any case anything beyond a foot or two is probably too much.

Edit: following @atomicbob and his measurements of the high-pass effect of cables after a goldpoint passive, in those cases I put the devices right next to or on top of each other and then measure with a tailor's tape measure and get the runs done by Gotham down to the cm measure.

 

Would it be better to place the preamp as close as possible to the amp and run a longer cable from the DAC then? And then theres cable length between the amp and transducers to consider too, but considering modern amps have output impedance in the less than 5 range, would that pose a problem?

 

Yes, it's the best way, but... Real life scenario, with solid cables means you can do whatever you want and it'll be fine. Also, adding a buffer after the preamp if it's passive isn't a bad idea if you're gonna run long thin cables, and/or your output impedance is high. For the speaker cables, linkwitz has a good rule of thumb, here: http://www.linkwitzlab.com/Amplifiers-etc/Connections.htm

 

May I ask another n00b question? It's about gain and wattage.

I never really understood what gain was. All I knew was that higher gain means higher volume. This is obviously evident on amps with switchable gain (e.g. many Schiit amps), you flip the switch to high gain and the volume noticeably increases. Of course, increasing the gain also increases the background noise, if there is noise.

But I also know that amps have their wattage ratings. For example, the CTH is rated 1 wpc into 50 ohms. Generally speaking, higher wattage means more power and thus louder volume (i.e. has the potential to make the headphones sound louder). If I were to feed a headphone with 50 ohms and 90 dB/mW sensitivity, the CTH would be able to make it sound loud up to 120 dB (since 1 W = 10^3 mW, and 90 dB * 10^3 = 90 + 10*3 dB = 120 dB). Or is it?

Let's take CTH for example again. According to the specs sheet, it said it has a gain of 8 (=18 dB). I learned that every time gain is multiplied by 2, the dB increases by 6. Therefore gain of 8 = 2^3 = 6*3 dB = 18 dB. Fair enough. But what does this mean for the CTH? The CTH, according to the calculation in the above paragraph, should only go up to 120 dB. But if the gain is 18 dB, does it mean that it could go up beyond that? To 138 dB? What if there is another amp, that has the same power rating as CTH (1 wpc into 50 ohms), but has a gain of 16 (=24 dB)? How loud will that go?

To summarize, let's say that there is a headphone with 50 ohm load impedance and 90 dB/mW sensitivity, and two amps (A and B) which are both rated 1 wpc into 50 ohms but have a fixed gain of 8 and 16 respectively. In this case, how loudly can each amp drive the headphone up to?

1) A: 120 dB / B: 120 dB (in this case, both amps cap out at 120 dB regardless of their difference in gain)
2) A: 138 dB / B: 144 dB (in this case, the amount of dB from gain is added to the sensitivity of the headphone)
3) both answers above are wrong, in which the correct answer is?

I'm asking this because when owning difficult-to-drive headphones like Code-X or HE-6, I always looked for amps with high wattage ratings, but overlooked the gain. When I compared CTH and Liquid Platinum with the Code-X, I expected the LP to be significantly louder because it had a higher wpc (4.21 wpc into 56 ohms versus 1 wpc into 50 ohms), but honestly I couldn't hear much difference in volume. Then I realized that the LP, despite having higher wattage, had lower gain (5(14 dB) vs 8(18 dB)). Which made me wonder, exactly what role does gain play? If both gain and wattage attribute to higher volume, then what is the difference between, say, a amp that does 1 W/20 dB gain and another amp that does 10 W/10 dB gain?