D&b rigs

[timperrett]

Can I ask whether 'AdamJames' has had the pleasure of utilising any of the d&b audiotechnik systems?

 

And also whether he has had the enlightenment from attending one of their training days?

 

 

Regards

P.S. Don't diss people, gently correct and rebuke with grace

[Mark Payne]

Hi all

 

Interesting reading! Lets keep the debate alive and respect to all!

 

We had a stock of perfectly good amps when we moved to d&b, yes it can be frustrating but once a few things are understood about d&b "systems" ... things become clear.

 

I have only scan read the posts so I cannot remeber who said what! I am also on my third glass of red wine ;-)

 

1. Sense drive

 

This is a feature for subs only. Its is standard with a B2 being driven from an A1 amplifier for example on CACOM . The point is that if you can measure the back EMF at the the speaker then you can modify the drive current in a closed loop control system at the amplifier.

 

This helps to remove the effect that longer speaker cables can have on low impedance critical applications (like with subs). The effective damping factor of the amplifier/cable/speaker system is increased. The amplifier can better control the cone movement and "grip" the speaker with sense drive.

 

The sense drive is simply a voltage measurement feed back to the amp.

 

The C7 sub has always also had pin 5 of the EP5 wired to pin 4 and is hence "sense drive ready". However the P1200 amplifier does not include sense drive capability so it was pointless but.....

 

The D12 is a different matter. This uses sense drive in the same way as the A1 does. .... so providing you use C7 sub with D12 amps AND you use 5 wire EP5 cables, you get the damping fator impovements inherent with sense drive.

 

Remember this has nothing to do with the tops, .... subs only.

 

A C7 rig is louder by a few db on D12 compared to P1200.... but to be honest... this is not the main advantage over P1200. The main advantage of D12 is the configuration support (all speakers without module changes) and the front end (delays and eq and cardioid support (not c7)). Its a big fat epac.

 

The d&b System. Marketing or Engineering?

 

You like the BMW M3 but you want it with the Merc V8 block and the engine management system out of the 1993 ford cosworth? Why would you do this? We buy the package (in my case a Scoobie STI with the PPP ;-)

 

Its a design thing.

 

Physical speaker design can maximise:

1.Power handling

2.Efficiency

3.Control of dispersion

4.Frequency response

5. Phase response

6. Distrotion

7. Dynamic respose

8. Size (make it small)

9. Weight (make it light)

10. Reliability

 

... but the design is a compromise and we cannot get the best of all worlds

 

so... give me bags of 2, 3, 5, 7. minimise 6 and dont care so much for 4 and you have maybe the d&b approach. We can fix 4 in the amplifier module.

 

Also if you look at cone failure and study it, they either shatter mechanically (too much cone excursion) or they burn out thermally (to much voice coil temperature).

 

Its not obvious how these things interact. For example voice coil temp is reduced by lots of cone excersion as air is pumped over the coil....

 

The point is that if you fully "know" how your speaker will move and heat up in terms of the program material by lab testing and measurement then you can model intelligent speaker protection in the amplifier. This is way beyond simple limiting, BSS XTA and KT cannot do this for you, only d&b can because they have destroyed may drivers along the way in the testing. This is engine management. It is however an open loop control system (there is no feedbacksystem). Actually the feedback loop is historically encoded into the control models in the P1200 modules or D12 DSP.

 

So with intelligent protection you can push closer to the red line in serch of better performance.

 

So get the M3 with the BMW engine, BMW engine management, BMW gearbox and BMW transmssion... unless you are ready to design a better car.

 

I reserve the right to not make any sense due the the hour of the day and red wine intake ;-) I also reserve the right to be really b o r I n g.

 

Cheers

 

Mark

[alsmyth]

Mark, That was interesting, I am also looking at a d&b rig, I want to replace a mish mash, which is working well and gets praise, with either d&b KV2 or Nexo. they are all shed loads of dosh, has anyone had chance to compare relatively similar rigs, at the same time, or is it a case of trying to remember the last rig you heard, and rely on specs and reviews. Its for live use for up to 2000 cap. ven. / outdoor, and must fit in a LWB sprinter. In case you are wondering our current gear is Void / HZ / Custom. Cheers all.