|
Audio • XLR Adapter/Preamp • Rebuff Beachtek Headroom Data
|
|
Solutions for Camcorder/Location Audio |
|
650-575-3249 |
|
Here at juicedLink, we wanted to take a moment to address some of the data that is currently (as of this post) on the Beachtek website. This is regarding headroom comparison data that they provided on the Beachtek DXA-2S dual XLR audio adapter. The same circuitry is also used on the Beachtek DXA-4, Beachtek DXA-4P, and Beachtek DXA-6A dual XLR audio adapters.
|
|
RELATED VIDEOS: |
|
Here at juicedLink, we wanted to take a moment to address some of the data that is currently (as of this post) on the Beachtek website. This is regarding headroom comparison data that they provided on the Beachtek DXA-2S dual XLR audio adapter. The same circuitry is also used on the Beachtek DXA-4, Beachtek DXA-4P, and Beachtek DXA-6A dual XLR audio adapters.
I can’t show you a closeup of their page, because of copyright. But, let me describe what they’ve done.
They’ve input a -3dBu waveform into a Beachtek DXA-2S XLR Audio Adapter and a juicedLink, and have scope pictures comparing the output.
One shows the output of the Beachtek DXA-2S XLR Audio Adapter vs juicedLink at high gain. The Beachtek DXA-2S XLR Audio Adapter shows a clean waveform, and the juicedLink’s is distorted.
Another plot compares the Beachtek DXA-2S XLR Audio Adapter versus juicedLink at medium gain. Again, the Beachtek DXA-2S XLR Audio Adapter shows a clean waveform, and the juicedLink’s is distorted.
The last plot compares the Beachtek DXA-2S XLR Audio Adapter vs juicedLink at low gain. Both the Beachtek DXA-2S XLR Audio Adapter and juicedLink plots look clean. But, the amplitude of the Beachtek DXA-2S XLR Audio Adapter is much higher than the juicedLink.
OK, so what’s going on here? Well, mixers have what is known as “headroom”. That is the maximum signal that the mixer can handle. The question is how much headroom is enough.
Let’s understand what’s behind the numbers. So, they’ve input a -3dBu signal, which is the same as about 550mVrms.
What does this mean in terms of how loud of a sound can it handle? So, we need to convert this voltage to Pa. Well, the some of the most sensitive mics that I know of are around 70mV/Pa. More typically, something like the Rode NTG2 is around 15mV/Pa.
So, Beachtek has input the equivalent of about 8-36 Pa.
So, let’s put this in perspective. My speaking voice at 1m is about 0.002 Pa. A jackhammer at 1m is 2 Pa. In fact, hearing damage due to long term exposure is 0.6 Pa.
So, if hearing damage is at the level of 0.6 Pa, and you are inputting a signal in the range of about 8-36 Pa, then you wouldn’t be using the juicedLink in the high gain or medium gain range. If you’re inputting a signal that is high enough to make your ears bleed, then I think it’s fairly obvious that the low-gain would be your best choice.
So, the plots comparing to juicedLink at high and medium gain don’t make sense.
So, what about the plot showing the difference in the signal level between the Beachtek DXA-2S XLR Audio Adapter and the juicedLink when it’s at low gain?
Keep in mind that these are designed to interface with the microphone input on camcorders. The typical maximum signal level that they can handle is less than 30mV. Anything above that would be clipping, and sound like crap.
So, 550mV is an enormous signal level. So, it’s obvious that you wouldn’t use the juicedLink on medium or high gain. In fact, even in low gain, you’re going to be turning down the volume control to attenuate that 550mV and bring it underneath the 30mV window of the camcorder.
If you took the output of the Beachtek DXA-2S XLR Audio Adapter shown on the plot, and input it into a camcorder which can’t handle more than 30mV, then it would be completely distorted and sound like crap. On the Beachtek DXA-2S XLR Audio Adapter, you will need to turn down the volume control to attenuate the signal and bring it to the same level.
So, the data presented comparing the juicedLink vs the Beachtek DXA-2S XLR Audio Adapter basically shows that the juicedLink can have headroom up to about 8-36 Pa, well beyond the ear bleeding level of long term hearing damage of 0.6 Pa.
If that’s not enough headroom for you, you can always use the juicedLink’s mic/line switch and set it on the line setting, giving you another 40 dB of headroom.
So, with a little understanding of the meaning of the numbers, the data that Beachtek has posted shows you how the juicedLink has GOBS AND GOBS of headroom.
Remember, a passive adapter like these Beachteks don’t have low-noise preamps. So, you won’t be able to use preamps to throttle back the noisy camcorder amps to get better system noise performance while recording fine audio detail, like you would using juicedLink. And now, you understand that juicedLink has gobs and gobs of headroom too.
So, I’d like to thank the folks over at Beachtek for posting that data and giving me the chance to show you just how much headroom the juicedLink has, and I’d also like to thank YOU for watching.
Copyright © 2007-2009 juicedLink, LLC. All rights reserved
|
|
We try to educate/inform you. Please make your purchase from our site. |
