Good luck finding one who doesnt have a DSP nowadays 
and sell your Denon kit, because it too adds latency.
That said, if you want to time align an analog sub/sub system (which is highly advised to make sure you dont cancel out sound around the crossover frequency), you may want to align up to 180 degrees (the other half of 360 degrees is done by the phase reverse button). At 70Hz this is 7.14milliseconds. You can do this digitally, but some smart guys have done this with coils and capacitors in the past. The clue here is that you modify the phase response of your system, and phase response is another word for time delay, its just a different time delay for every frequency⌠All this goodness is called IIR filtering (digital or analog), and means you delay your tops typically around 5ms in relation to your subs not to have cancellation or comb filtering.
The problem here is that your frequency response may be flat, but your phase response isnt flat. Imagine someone hitting a snare or a kick drum. You expect the high attack to come before the low end and the sizzle: You expect the snare to sound âsnappyâ. But a system with a bad phase response smears this out, resulting in less intelligibility in spoken word, or snappiness in musical terms. This is what an impulse response is about. Enter FIR filtering, something most big brands are doing these days. This lets you flatten the phase response separate from the frequency response and improve the impulse response (impact of that snare hit) vastly. Disadvantage here is that you buffer your audio stream, to âlook aheadâ, and do calculations based on the audio samples that are further up in the buffer. Actually an (analog or digital) IIR filter does something similar, because a filter physically can not know which frequency it filters (quantum physics anyone?), before a significant part of the wave has come through, but it masks this in a shifted phase response. Looking at my FIR-filtered RCF settings I have to add 6,1ms to my subs (which are IIR) to follow my tops (which are FIR and thus buffered). That equates to 2.1m extra distance. Ive played on speaker sets further away from me than 2 meters
To compare, every digital system in the chain adds under 1ms: an SC6000, an x1850, a FOH desk, and your speakers DSP together is under 4msâŚ
conclusion: digital filtering latency isnt that bad. The real bad boy is the phase response: time and phase aligning your system means latency, analog or digital, IIR or FIRâŚ
And of course donât forget the harmonic distortion of a (shitty) driver: if your cone starts warping you can throw all the filtering you want at it, it will still be a shitty driver⌠Many brands use the FIR or DSP word as a marketing term. But decent drivers cost big moneyâŚ
Im 100% with you on the bluetooth thing though. For the OP: no, you cant use bluetooth to connect your DJ equipment to your speakers, unless you are ok with 300ms delays. You cant DJ, let alone play live music with these kind of delaysâŚ
