DIY Subwoofer newbie

I'm a little "concerned" about the 2x1500W@4ohms of the Proline 3000.
As the amp don't have a DSP, wouldn't it be wise to use an miniDSP to implement an HPF to avoid damage the driver? The 3 bands of the UMC-200 should be enough to smooth the frequency response, and i was thinking in trying without the miniDSP.

But the guarantee that the driver would be protected with a HPF wouldn't justify the cost of the miniDSP?

By the way, i'm planning on doing a near-field measure of my subwofer, in order to verify how the room interacts with the subwoofer, trying to gather some information of the room gain i can expect with the new sub.
 
So i took some measures, a near field measure, and one in the seating position.

1 - Near field
Nearfield_zpsxqrctygy.png


2 - Seating position
mic_placed_zpscortefuo.png



Here are the results of the two measures:
Near-seat_zpssbdly42v.png


Measure in the seating position, as expected, is -13,9db than the near field measure.
Nevertheless, i dont know what to conclude from this two measures.

@Mattkan, could you please help me understanding this measures? My mdat file can be downloaded here.
 
I'm trying to understand Room gain, in order to predict what the response in the seating position would be, with the DIY sub.

The near-field measure confirms that the room suck a lot of sound in the 25-100Hz region, with some big peaks in between (peaks that are easily treated with PEQ).

As the BMS has a greater response in the > 30Hz, those measures seems to indicate that the driver was a good choice, as the room itself provides a lot of SPL in the < 25Hz region.
 
did you plug the port when taking these measurements?

I would also take a few measurements at different positions around the room (but not right near the walls) to understand the nature of gain more clearly.
 
No, you can see from the picture that the port is unplugged.

Here is the layout of the room, sub is the left light blue square, and seating position in in the middle of the dark rectangle. Any suggestion on the different positions around the room?

room2_zps90ba8d13.png
 
So is it safe to say your room is around 6.5m wide x 5m / 5.5m!! all a guesstimation but it doesn't lend itself to a great response! from a sub position or/and mlp.
 
You just need to take some measurements that vary on each axis, go say 0.5m in each direction (up/down/left/right/forward/back). Do this with the port plugged as you can't directly compare a nearfield driver measurement with an in room measurement unless you've stitched together a measurement of the port output with the driver output, simpler just to plug the port instead.

@mojogoes IIRC the room is an irregular shape (ceiling maybe?) so raw dimensions don't tell the whole story
 
0,5m from the sub, or from the seating position?

Should the seating position measure be with the plug ported too?
a nearfield measurement should be about 1" from the centre of the dustcap with the port plugged
in room measurements in a zone around the LP also with the port plugged
 
Fresh Measurements :)

Nearfield, with port plugged
Nearfield-sealed_zps9hjiy7yq.png


And the measurements from the following positions:

  • Nearfield
  • Seating position (LP)
  • Seating position (LP) - 0,5m forward
  • Seating position (LP) - 0,5m Left
  • Seating position (LP) - 0,5m Right
  • Seating position (LP) - 0,5m down
(Couldn't take up and back measures)

All_zpsjj1b0w50.png


Mdat file here.
 
I'm really not sure what to make of that, it suggests there is absolutely no room gain whatsoever down to 15Hz as the slope of the rolloff doesn't change at all. The dip at 45Hz in the nearfield is also rather confusing. I assume there was no EQ applied to this signal right?
 
The dip at 45Hz in the nearfield is also rather confusing. I assume there was no EQ applied to this signal right?

I think i made a mistake :(
The 2 dips at 46Hz and at 87Hz are the exact frequencies i have a specific PEQ filter, namely:
* 46,8Hz; -8db; 3Q
* 87,04Hz; -10db; 12Q

Thank you for alerting me, i forgot to disable PEW :(

Please discard this measures, i will have to take new ones next week ...
 
you don't want to use speaker cable for a line level signal ... thread to explain - https://www.gearslutz.com/board/low...-between-using-microphone-speaker-cables.html

According to the mentioned thread :
... speaker cables for amp >>> speaker
For mixer >>> amp or powered monitors use "audio cables"

So, i will need the following cables:

1 - Processor - Amp => Mic cable + Neutrick XLR plugs
Mark Grant uses Canare L4E6AT star quad balanced (2,6€/m) on his XLR cables
Another option could be Mogami Neglex Quad Microphone Cables

2 - Amp - Sub => Speaker cable + Neutrick plugs
The 4.00mm Sommer cable is a good and cheap option.

@mattkhan, can you please confirm this is correct?
 
Thank you very much (that was fast :)). The wiring will be made by the store, i'm not very handy with a solder !!!
 

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