d&b Q1/Q7 - Ported?

Hello,

Yes they are ported at the back.

One of my favourite boxes of all time! 

Sounds shitty on any given amp.  But sounds sweet on one of their own amps! Then later Processed or not. It sounds gooood! And that's what it's all about

So do you think it sounds good or shitty on any given unprocessed amp?

I was shocked when i saw how those boxes are processed.

By the nature of this design an unprocessed signal will be uneven. The angled drive units cause a path length difference between the front and back part of the cone which will cause cancellations at certain frequencies. The chamber in front of the drive unit is basically a short pipe, which will have a resonant frequency.

Based on a 10” drive unit, I would expect a peak in response between 300Hz – 400Hz and interference cancellations start to be come pervasive above 700Hz. I can’t remember seeing a published crossover frequency, processor settings, or a graph of the response, but using electronic processing to obtain a good response is a valid design method, so the above observations are not a criticism of the cabinet. When bought new, I guess that customers buy into the whole d&b ecosystem. But for people buying just the cabinets second hand, the lack of processor settings could trip them up.

For anyone building a similar design, I would suggest fitting a baffle in front of the drive unit, with a slot cut in it, which should extend the upper response slightly. With some thin, cheap ply, it would be easy to experiment with the size, shape and position of the slot to optimise response. Extending the upper response by only 100Hz would increase the options of compression driver choice. It would still need significant eq, but easily doable with a dsp.

Well.......... I am going to chip in here.

jacethebase wrote: Well.......... I am going to chip in here. Q7 and QSub on a PLM sounds the nuts!