Solen caps in NHT SuperZero make trumpet sound harsh and ear-hurting

[Kreshna]

About two weeks ago (September 15, to be exact) I replaced the crossover capacitors of my NHT SuperZero with Solen caps. I noticed the overall sound became less grainy and more fluid, especially cymbals and hi-hats. My wife is not an audiophile, so she doesn't understand audiophile jargons like "grain", but she told me that the sound becomes cleaner.

However, I also noticed that trumpet becomes very harsh and ear-hurting.

I once drove B&W DM302, difficult load speakers, with Sansui A-40, which is underpowered for the job. The sound becomes harsh and ear-hurting due to the distortion. But this time, it is not the same kind of harshness.

First, trumpet is the only instrument that sound harsh. Other instruments like Herbie Mann's flutes and Louis Armstrong's vocals sound nice and lifelike.

And then, while trumpet sounds really harsh and ear-hurting, it also sounds very clean and lifelike. I cannot hear any distortion accompanying the harshness. Trumpet sounds very alive, very real, probably due to the lack of distortion. But it also sounds very harsh that it hurts my ears. Louis Armstrong's songs become heavenly and hellish at the same time. Armstrong's vocals sound really nice, clean, and fluid, but when the trumpet comes then I'm ready to close my ears.

Trumpet also sounded harsh before recap, but not as ear-hurting as now.

I wonder, do capacitors need to break-in? I've been very busy, so I've only listened averagely an hour per day. So the speakers have only been used about 15 hours since recap. Perhaps it would take 100 hours of burn-in until trumpet sounds nice?

 

[stickman]

The Solen caps tend to have lower series resistance than most film caps and are very good at passing high frequency transient signals unmolested compared to say Dayton brand caps which have a more typical response. This can often cause certain treble frequencies and instruments to sound more prominent than with other caps which can make them sound harsh or strident.

In your case I would expect it is how the trumpets have been recorded that is more likely the cause of the perceived harshness more than the Solen caps as passing signals through in a more accurate manner quickly reveals shortcomings in the source material or electronics being used to drive the speakers. Trumpets produce their fair share of harmonics which if reproduced more accurately in the upper frequencies can make them sound harsh due to nature of the instrument itself. Trumpets by their very nature can easily sound harsh (I played trombone through high school often sitting next to the trumpet section) so I don't expect that your Solen caps will break-in in a manner that will materially change the perceived sound of trumpets as I'd guess they are providing a more accurate rendition of what the recorded signal actually sounds like as unpleasant as that may be! (lol).

 

[Blue Shadow]

Caps can take time to break in. I have read that Solens might be brighter than other caps. This can manifest itself as harshness or if not harsh, fatiguing. Sure would be nice to know what to use when. There are cap reviews out there and obey must read them with knowledge of there expected use. Let em play a while and let us know if there is a change.

 

[Kreshna]

In your case I would expect it is how the trumpets have been recorded that is more likely the cause of the perceived harshness more than the Solen caps as passing signals through in a more accurate manner quickly reveals shortcomings in the source material or electronics being used to drive the speakers. Trumpets produce their fair share of harmonics which if reproduced more accurately in the upper frequencies can make them sound harsh due to nature of the instrument itself. Trumpets by their very nature can easily sound harsh (I played trombone through high school often sitting next to the trumpet section) so I don't expect that your Solen caps will break-in in a manner that will materially change the perceived sound of trumpets as I'd guess they are providing a more accurate rendition of what the recorded signal actually sounds like as unpleasant as that may be! (lol).

I see!

I need to get used to it then.

For some reason I don't understand, my wife loves the sound of the SuperZeros so much despite she's not an audiophile, and she is apparently more resistant to the trumpet's harshness than I am. What she cannot stand, by the way, is the sound of B&W DM302, which is veiled and lacking clarity according the her.

The Solen caps tend to have lower series resistance than most film caps and are very good at passing high frequency transient signals unmolested compared to say Dayton brand caps which have a more typical response. This can often cause certain treble frequencies and instruments to sound more prominent than with other caps which can make them sound harsh or strident.

I found an interesting article here. The author has recorded the spectrum of various musical instruments, and he found trumpet has very strong harmonics between 1.6 kHz to 2 kHz, as shown on the picture above (not mine, it's his).

Trumpet has very strong harmonics from 1600 Hz to 2000 Hz, as shown by the grey bar. The said harmonics is even stronger than its fundamental frequencies.

On the other hand, the original NHT SuperZero (the A450 and the XU; the latter is what I own) has very strong peak at 2000 Hz. Is that the reason why trumpet, despite having such clean and fluid sound, sounds very harsh on my SuperZero XU?

The original NHT SuperZero (the A450 and the XU) has peak at 2000 Hz; is that what makes trumpet sound harsh?

It is interesting to note that trumpet also sounds harsh on B&W DM302, though not as severe as it is on SuperZero. Perhaps because DM302 has second (and slightly higher) peak at 1000 Hz, that makes the entire sound warmer?

Bowers & Wilkins DM302 is also peaked at 2000 Hz, but it has higher peak at 1000 Hz. Perhaps it's what makes the trumpet sound (slightly) less harsh.

What if I use NHT SuperZero 2.1, which is voiced differently than the original NHT SuperZero? Instead of peak at 2 kHz, the SuperZero 2.1 actually has dip at 2 kHz, which may make trumpet sounds less harsh. Also, the curve keeps rising from 9 kHz, up to 20 kHz and perhaps even above it! Does it mean that cymbals and hi-hats will sound airier on the SuperZero 2.1 than on the original? Because airy cymbals and hi-hats is exactly what I'm looking for; it is the reason why it's hard for me to part with JBL titanium dome tweeters.

NHT SuperZero 2.1 has dip at 2000 Hz; will it make trumpet sound less harsh? And will cymbals and hi-hats sound airier on the 2.1?

At last, since you mentioned resistance, how about putting a resistor in series with the Solen cap? Will it tame the trumpet? However:

1. What resistance would be the best? Will 2 ohms better than 1 ohms? Or is it the other way around?
2. NHT SuperZero's crossover has two capacitors: 4.7 uF and 8.2 uF. Which capacitor need to be tamed with resistor? Or perhaps both?

Caps can take time to break in. I have read that Solens might be brighter than other caps. This can manifest itself as harshness or if not harsh, fatiguing. Sure would be nice to know what to use when. There are cap reviews out there and obey must read them with knowledge of there expected use. Let em play a while and let us know if there is a change.

How long for a typical Solen cap to break in? I have probably use the speakers for about 15 hours at most (an hour a day on average, and it's already 2 weeks).

 

[sqlsavior]

However, I also noticed that trumpet becomes very harsh and ear-hurting.

Kinda like sitting in front of the trumpet section?

https://www.bbc.com/news/entertainment-arts-43571144

Congratulations on the high fidelity!

 

[Kreshna]

Kinda like sitting in front of the trumpet section?

https://www.bbc.com/news/entertainment-arts-43571144

Congratulations on the high fidelity!

Ouch!

Yes, it's kinda like that. In fact, it hurts!

 

[guest136]

My 2 cents .bargain solen caps not considerd hi end right,,yes 100 hours run time about right to find out if u can live with them . black solens only cost $3.50 2uf come on man ,i used to buy cheap polys when starting out .now you can get good tweeter caps $6 to 20 dollars..i agree black solens blow away dayton caps and audyn q4..this might sound funny try different kinds of 1ohm resistors for that sound you want ,post a graph of the crossover ..there is about 4 different places you can alter sound with resistors

 

[rothwellaudio]

However, I also noticed that trumpet becomes very harsh and ear-hurting...
First, trumpet is the only instrument that sound harsh. Other instruments like Herbie Mann's flutes and Louis Armstrong's vocals sound nice and lifelike.
Trumpet also sounded harsh before recap, but not as ear-hurting as now.

It is interesting to note that trumpet also sounds harsh on B&W DM302...

How many recordings of trumpets have you been listening to? My guess, same as stickman, is that it's a harsh recording. If your speakers make Chet Baker sound harsh maybe there's something wrong with them.

 

[StimpyWan]

The ClarityCaps I've used took weeks to fully settle in, so I'd give the Solens more time to burn in. This should help reduce the brightness. You could also add a small value film cap as a bypass. 0.1 to 0.01uF in value. I've found that the bypass cap will help tame sibilant caps. And if you consider adding a series resistor, something between 0.3 to 0.5 Ohms, is typical in replicating cap ESR resistance.

 

[Kreshna]

How many recordings of trumpets have you been listening to? My guess, same as stickman, is that it's a harsh recording. If your speakers make Chet Baker sound harsh maybe there's something wrong with them.

Well, @stickman said trumpets by their very nature can easily sound harsh, perhaps because they produce their fair share of harmonics, which if reproduced more accurately in the upper frequencies can make them sound harsh due to nature of the instrument itself.

So I guess real trumpets in real life sound harsh indeed, which is accurately reproduced by the help of Solen caps inside my SuperZero.

In any case, the trumpet in many Louis Armstrong's songs sound really harsh, hellish, and ear-hurting, although other instruments and Armstrong's vocals sound very clean and heavenly. Also, Walkin' by Miles Davis (from the album At Plugged Nickel) hurts my ears. However, the worst offender is African Rhythms by Oneness of Juju. But no, those Youtube videos doesn't do justice, since they sound less clean than my CDs. Strangely, trumpets sound less offensive from "dirtier sounding" sources like Youtube.

 

[StimpyWan]

Hey Kreshna,

Do you remember the cap values in your Zeros? I have several different sets of NHT's, including Super Zeroes. Maybe I'll do a recap, and see how they sound after. I'm not sure how many jazz trumpet recordings I have, but I have some classical pieces with horns, that I could try.

 

[Kreshna]

Hey Kreshna,

Do you remember the cap values in your Zeros? I have several different sets of NHT's, including Super Zeroes. Maybe I'll do a recap, and see how they sound after. I'm not sure how many jazz trumpet recordings I have, but I have some classical pieces with horns, that I could try.

4.7 uF and 8.2 uF. Mine are NHT SuperZero XUs, which belong to the same generation as NHT SuperZero A450 (the original).

 

[Kreshna]

The ClarityCaps I've used took weeks to fully settle in, so I'd give the Solens more time to burn in. This should help reduce the brightness. You could also add a small value film cap as a bypass. 0.1 to 0.01uF in value. I've found that the bypass cap will help tame sibilant caps. And if you consider adding a series resistor, something between 0.3 to 0.5 Ohms, is typical in replicating cap ESR resistance.

Thank you, I'll definitely do it.

How many hours did it take for your ClarityCaps to settle, by the way? I have listened to the recapped SuperZero for two weeks, but only an hour a day averagely.

 

[StimpyWan]

Thank you, I'll definitely do it.

How many hours did it take for your ClarityCaps to settle, by the way? I have listened to the recapped SuperZero for two weeks, but only an hour a day averagely.

The ClarityCaps took several weeks to smooth out, playing 3 to 4 hours a day. But, they were the exact opposite of the Solens. Instead of too peaky, they were too muted. No upper mid air or clarity. That partially went away with burn in. The addition of the bypass cap smoothed them out even more, and brought out detail without adding harshness.

 

[Kreshna]

The ClarityCaps took several weeks to smooth out, playing 3 to 4 hours a day. But, they were the exact opposite of the Solens. Instead of too peaky, they were too muted. No upper mid air or clarity. That partially went away with burn in. The addition of the bypass cap smoothed them out even more, and brought out detail without harshness.

I see.

Anyway, NHT SuperZero's crossover has two caps: one 4.7 uF, and another 8.2 uF. At which capacitor should I put the resistor and the bypass cap? Or both?

 

[guest136]

I doubt its the solens bothering you ,consider ing the tweeter signal passes through a 10watt 3ohm sandcast resistor .Can you discribe if the harshness is from tweeter or woffer or both , The original caps where electrolytic.

 

[StimpyWan]

I see.

Anyway, NHT SuperZero's crossover has two caps: one 4.7 uF, and another 8.2 uF. At which capacitor should I put the resistor and the bypass cap? Or both?

I would think the 4.7uF, is the tweeter high pass cap. Though, without seeing a crossover schematic, that's a guess. But, it wouldn't hurt anything to add a bypass cap to both capacitors. That's what I do. The Parts Express film bypass caps are around a $1.00, so not expensive to try on both.

 

[Kreshna]

I doubt its the solens bothering you ,consider ing the tweeter signal pass through a 10watt sandcast resistor .Can you discribe if the harshness is from tweeter or woffer or both , The original caps where electrolytic.

I cannot tell. NHT SuperZero drivers have such coherency that the sound comes from one source instead of individual drivers. All I know is trumpet sounds harsh and ear-piercing, but also sound clean and lively despite the shrill.

The overall sound became cleaner as well after recap. Hi-hats, cymbals, Louis Armstrong's voice, etcetera.

 

[Kreshna]

I would think the 4.7uF, is the tweeter high pass cap. Though, without seeing a crossover schematic, that's a guess. But, it wouldn't hurt anything to add a bypass cap to both capacitors. That's what I do. The Parts Express film bypass caps are around a $1.00, so not expensive to try on both.

I see, thanks again. I have PDF manual for NHT SuperZero A450 and NHT SuperZero XU, but neither has crossover schematic.

I wonder what the 8.2 uF cap is for, since the SuperZero only has one crossover point (two way speaker). Or does it?

 

[ra.ra]

First, trumpet is the only instrument that sound harsh.

Ouch!.....My ears are still ringing from a Maynard Ferguson concert in Milwaukee in 1977.