Review of DJ equipment?

[Wavez]

@nagster am I reading this measurement right?
The cdj-3000x has a MINUS TEN DB hole with steep slopes at 2000hz?!?!

 

[Reticuli]

@nagster am I reading this measurement right?
The cdj-3000x has a MINUS TEN DB hole with steep slopes at 2000hz?!?!

That's with master tempo on. IIRC, there were some other classic key change algorithms that also had a similar notch. Engine OS's Elastique Efficient is superior key correction, but that's additional to the more computationally efficient, aggressive, and 'leaky' firmware's DSP sound quality. So, if you're going keylock off, the CDJ-3000X will provide superior sound. If you're using key change aggressively, it's either a wash or the Denon DJ Prime stuff will sound superior, YMMV. In my experience, the sonic defects of Engine OS are less noticeable with sparse, dynamic, real musical content, and more of an issue with dense, artificial content with distortion already baked into the production. The Engine OS processing also seems more geared to imperfect live environments, while the CDJ-3000X firmware's sound, while thriving in controlled audiophile environments, might not be as strong in some live DJing situations. Seems to come down to digital signal processing methods and philosophies behind the compromises they chose.

 

[nagster]

@nagster am I reading this measurement right?
The cdj-3000x has a MINUS TEN DB hole with steep slopes at 2000hz?!?!

Yes, the measurements show what you are saying. There was a strange dip in the FR.
Could you perhaps perform your own measurements when you have the chance to use the CDJ-3000X? Especially if the results are unexpectedly good or bad, I do various checks before publishing them, but I cannot say that there is a possibility that the drop in FR is a problem specific to my measurement environment. Having a third party replicate the results would be ideal.

You can verify this using free measurement software (such as REW, MTA, or ARTA/STEPS), a USB flash drive, and a computer equipped with a line input. High-precision equipment is not required. The necessary settings and conditions are detailed in the images I posted. For instance, try comparing amplitudes at frequencies such as 100, 300, 1k, 1.7k, 1.8k, 1.9k, 2k, 2.1k, 2.2k, 3k, and 10 kHz.

I measured two CDJ-3000 units and one CDJ-3000X unit, and all of them yielded similar results. Concerned that there might be an issue with frequency sweeps, I also performed spot measurements, which produced the same outcome. Although I didn't post the data, I verified the CDJ-3000's frequency response using an R&S UPV and a Keithley 2002 before publishing my findings. Since all the instruments showed consistent results, I released the FR data obtained with the APx555. For the CDJ-3000X, however, I did not verify the results with any instrument other than the APx555.

 

[nagster]

Photos and measurements of the GSA ISO-3001 DJ Isolator.
Input/Output impedance, Square wave response.
(Continued below)

 

[nagster]

Measurements of the GSA ISO-3001 DJ Isolator.
APx Dashboard, Frequency response, Group delay, Crosstalk, Distortion.
That is all.

 

[Reticuli]

That all looks quite standard, especially the test waveform group delay distortion, for a nice isolator, with only the THD and noise being higher than what you'd expect from a digital crossover network. Good analog performance. 2nd, 3rd, or 4th order? I always wondered if the MP2015's mids on the channels' tone controls were properly inverted. Is it opamps-based or discrete, because it did unusually well even with 4 volts?

 

[Reticuli]

After testing the Rane with saw waves, I can confirm the polarity is the way it's supposed to be for a 2nd order isolator on those channels.