SMSL DL100 DAC and Headphone Amp Review

[Mishaiger]

Hello, i recently bought headphones, 7Hz x Crinacle Zero:2 IEM. Now i think about purchasing this DAC+AMP. I'll be using 6.35mm headphone jack to connect headphones. I want to achieve SPL of 121dB. I know its too loud, still. Headphones is around 30 ohm, with sensitivity of about 108dB/V. My calculations show that i need about 900 mwatts to achieve this SPL. But I'm somewhat confused about output level Vrms. Does it matter? Can i achieve desired SPL with this DAC+AMP using 6.35mm headphone jack output?

 

[A Surfer]

Hello, i recently bought headphones, 7Hz x Crinacle Zero:2 IEM. Now i think about purchasing this DAC+AMP. I'll be using 6.35mm headphone jack to connect headphones. I want to achieve SPL of 121dB. I know its too loud, still. Headphones is around 30 ohm, with sensitivity of about 108dB/V. My calculations show that i need about 900 mwatts to achieve this SPL. But I'm somewhat confused about output level Vrms. Does it matter? Can i achieve desired SPL with this DAC+AMP using 6.35mm headphone jack output?

I'm super curious why you need such a high spl?

 

[JIW]

Hello, i recently bought headphones, 7Hz x Crinacle Zero:2 IEM. Now i think about purchasing this DAC+AMP. I'll be using 6.35mm headphone jack to connect headphones. I want to achieve SPL of 121dB. I know its too loud, still. Headphones is around 30 ohm, with sensitivity of about 108dB/V. My calculations show that i need about 900 mwatts to achieve this SPL. But I'm somewhat confused about output level Vrms. Does it matter? Can i achieve desired SPL with this DAC+AMP using 6.35mm headphone jack output?

Power is voltage squared divided by impedance. Thus, if it can produce the required power, its voltage output will be sufficient.

The sensitivity Amir measures is 94 dB SPL at 50 mV RMS, which is equivalent to 94-20*log10(50/1000) = 120.02 dB SPL at 1 V RMS or 0 dBV not 108 dB. Thus, 121 dB SPL requires 1 dBV or 1.12 V RMS. The DL100 can produce 1.5 W into 32 Ohm which is 10*log10(1.5*32) = 16.81 dBV. Much more than needed.

Amir measures the impedance at 29 Ohm. Thus, in the worst case of current limiting, voltage output is 29/32 lower than at 32 Ohm or 20*log10(29/32) = -0.86 dB lower, i.e. 15.96 dBV. Still more than enough.

 

[staticV3]

Hello, i recently bought headphones, 7Hz x Crinacle Zero:2 IEM. Now i think about purchasing this DAC+AMP. I'll be using 6.35mm headphone jack to connect headphones. I want to achieve SPL of 121dB. I know its too loud, still. Headphones is around 30 ohm, with sensitivity of about 108dB/V. My calculations show that i need about 900 mwatts to achieve this SPL.

For 121dB SPL Peak out of the Zero:2 you need 1.12Vrms, which at 29Ω translates to 43mW.

For this application, anything more than the Apple A2049 or JCally JM20/JM20 Max is utter waste.

 

[TheZebraKilledDarwin]

Hello, i recently bought headphones, 7Hz x Crinacle Zero:2 IEM. Now i think about purchasing this DAC+AMP. I'll be using 6.35mm headphone jack to connect headphones. I want to achieve SPL of 121dB. I know its too loud, still. Headphones is around 30 ohm, with sensitivity of about 108dB/V. My calculations show that i need about 900 mwatts to achieve this SPL. But I'm somewhat confused about output level Vrms. Does it matter? Can i achieve desired SPL with this DAC+AMP using 6.35mm headphone jack output?

Why do you want to destroy your hearing?

 

[Mishaiger]

Thanks for the replies. I want to compare Zero:2 headphones to 7.1 surround speaker system at reference volume (105dB per channel + 115dB LFE), and 121-122 dB is about max peak from all speakers combined, and this happens rarely in the mix and for short amounts of time, so probably not too bad for ears. I think I'll buy some headphone dongle for my purpose. Thanks again.

 

[A Surfer]

Thanks for the replies. I want to compare Zero:2 headphones to 7.1 surround speaker system at reference volume (105dB per channel + 115dB LFE), and 121-122 dB is about max peak from all speakers combined, and this happens rarely in the mix and for short amounts of time, so probably not too bad for ears. I think I'll buy some headphone dongle for my purpose. Thanks again.

You realize that with something right inside your ear it will cause significant damage quickly right?

 

[JIW]

Thanks for the replies. I want to compare Zero:2 headphones to 7.1 surround speaker system at reference volume (105dB per channel + 115dB LFE), and 121-122 dB is about max peak from all speakers combined, and this happens rarely in the mix and for short amounts of time, so probably not too bad for ears. I think I'll buy some headphone dongle for my purpose. Thanks again.

How did you arrive at the combined maximum?

Assuming perfect correlation between the signals and zero means, the maximum SPL is 20*log10(7*10^(105/20) + 10^(115/20)) = 125.14 dB SPL. For uncorrelated signals with zero means, this is reduced to 10*log10(7*10^(105/10) + 10^(115/10)) = 117.30 dB SPL.

 

[JeremyFife]

Thanks for the replies. I want to compare Zero:2 headphones to 7.1 surround speaker system at reference volume (105dB per channel + 115dB LFE), and 121-122 dB is about max peak from all speakers combined, and this happens rarely in the mix and for short amounts of time, so probably not too bad for ears. I think I'll buy some headphone dongle for my purpose. Thanks again.

Don't put that sort of SPL directly into your ears, even for short periods ... it's not nice for listening to music, and it's not worth it given the real risk to your hearing. Honestly, it's just not worth it.

 

[Yersinia Bestmate]

One loud sound impulse above 120dB can and probably will damage the delicate receptor cells in your organ of Corti, even if the impulse is very short.

I'd never willingly expose my ears to such noise, ~105dB at the listening spot is more than enough for me..

 

[Mishaiger]

How did you arrive at the combined maximum?

Assuming perfect correlation between the signals and zero means, the maximum SPL is 20*log10(7*10^(105/20) + 10^(115/20)) = 125.14 dB SPL. For uncorrelated signals with zero means, this is reduced to 10*log10(7*10^(105/10) + 10^(115/10)) = 117.30 dB SPL.

I simply added +6dB for every doubling in speakers. So, 1 speaker is 105 dB, 2 is 111, 4 is 117, 7 is about 121-122. LFE is always 115 dB, and while it adds SPL, but only to low frequencies. I'm not really sure about my logic, but it gives me approximate theoretical maximum.

For anyone worried about my hearing, thank you, but i know the dangers. In fact, i decided to record peak SPL from my test movies to get clear about what SPL I'm actually talking about. Measured using UMIK-1.

This blue line is 1 speaker REW sweep. Its 105 dB. Peaks and dips are result of me sitting here and holding mic, MMM gives a lot flatter response, anyway.
Red and green is some action scenes from two movies. This is their peak SPL. So while in theory SPL should combine to 120dB+, it only reaches to 110 dB bass, in this particular movie, and the rest of response is even lower.

 

[Robbo99999]

I simply added +6dB for every doubling in speakers. So, 1 speaker is 105 dB, 2 is 111, 4 is 117, 7 is about 121-122. LFE is always 115 dB, and while it adds SPL, but only to low frequencies. I'm not really sure about my logic, but it gives me approximate theoretical maximum.

For anyone worried about my hearing, thank you, but i know the dangers. In fact, i decided to record peak SPL from my test movies to get clear about what SPL I'm actually talking about. Measured using UMIK-1.
View attachment 447428
This blue line is 1 speaker REW sweep. Its 105 dB. Peaks and dips are result of me sitting here and holding mic, MMM gives a lot flatter response, anyway.
Red and green is some action scenes from two movies. This is their peak SPL. So while in theory SPL should combine to 120dB+, it only reaches to 110 dB bass, in this particular movie, and the rest of response is even lower.

To me those Movie 1 & Movie 2 peak levels experienced should be OK for your hearing, if it's just occasionally near those levels in the movie.