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Maybe to much bass


The Dude

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I have thought about cutting it in half, I will get a k-402 someday, and I do have a TH SPud. So we're getting there just slowly.

Spud is roughly the samer performance as a LAB tapped, horn so you are set there. So again. Slice those bad boys in half and put your money where it really counts, the best midrange horn ever made by any company out there, the Klipsch K-402 by Roy Delgado. It's a true REVELATION.

I wish I could simply cut one in half to make two. But I think it wouldn't turn out right. When I build my next one I could build it half size, but than the question would be, wouldn't a LaScala be just as good. I wonder what the difference in bass is.

 

La Scala is much shorter than the Jamboree, so won't go as low, plus the mouth is way out of the corner, so less extension there also. Find a giant bandsaw somewhere. It should be easy to cut in half.

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You can set the microphone up about 40 inches (~ one metre) in front of each loudspeaker being tested, and centered horizontally and vertically between the tweeter and midrange horn mouths looking up at about a 20-30 degree angle at the tip of the microphone.  I've found that works well as a starting point.

Edited by Chris A
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You can set the microphone up about 40 inches (~ one metre) in front of each loudspeaker being tested, and centered horizontally and vertically between the tweeter and midrange horn mouths looking up at about a 20-30 degree angle at the tip of the microphone.  I've found that works well as a starting point.

Here is a quick measurement from that area.

post-27403-0-13060000-1438723692_thumb.p

Edited by duder1982
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Looks like you're crossing over around 600 Hz.  If so, I'd back off on the bass bin gain by about 4-5 dB. 

 

If you press the "SPL & Phase" button on the top of the screen, you should see the relative phase of the response, and it should be able to tell you if your microphone position is working well.

 

The phase might be discontinuous at the crossover points, but you can adjust both the SPL and phase scales separately on the graph, as well as move the phase or SPL up or down to center them in the graph area, and even unwrap and move the phase by + or - 360 degrees by using the "Controls" dialog at the top right of the graph.

 

Chris

Edited by Chris A
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You can set the microphone up about 40 inches (~ one metre) in front of each loudspeaker being tested, and centered horizontally and vertically between the tweeter and midrange horn mouths looking up at about a 20-30 degree angle at the tip of the microphone.  I've found that works well as a starting point.

Here is a quick measurement from that area.

 

 

 

that is obviously "too much bass"! :D  if your audio source is a PC i suggest to use Dirac Live or IK Multimedia ARC 2

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jamboree.PNG

 

What are you using for your crossover and equalization?  If you have any parametric EQ (PEQ) filters, I'd recommend placing one at ~3 kHz with a Q of about 0.7 and a gain of about -3 or perhaps a bit more.  This will help to smooth out the arched response curve from 600 Hz to 20 kHz.  Then you can readjust the gain of the high frequency driver(s) to match the bass bin.  It also looks like you will need to boost the highs above about 7 kHz.  A shelf filter at about 6 kHz and a pretty big gain (6 or 12 dB/octave) will help.

 

You might also place a PEQ filter at 50 Hz with a Q of about 7 and a gain of about 7 to 10.  This will smooth out the low end of the bass bin, restoring the deep bass below 60 Hz. 

 

The phase information in the other plots is a bit more difficult to see at the top of the plots, but it looks like a few ms of delay on the HF channel would help to flatten the phase around the 500 Hz crossover point (assuming that you're using a digital crossover).

 

I'd recommend increasing the vertical scale resolution back to at least 5 dB/division or even less so that you can easily see the response at 1-2 dB resolution levels.  You can use smoothing of the trace at 1/24 octave or 1/12th octave to see the response without as much grass on the plot so it is a bit easier to see the trend when correcting overall EQ balance.

 

Hope some of this helps.

 

Chris

Edited by Chris A
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What are you using for your crossover and equalization?

 

Right now I am using a Minidsp, but am thinking about switching as this seems to introduce a lot of unwanted noise. 

 

Hope some of this helps

 

Yes it has, just turning down the gain on the bass bin like you said made a big difference.  I will try the peq filters your recommend to see how it sounds.  Its amazing how so little adjustments make a big difference.

 

One last question, what difference would it make if I crossed at 600 or 500? I am guessing it has something to do with the stress it puts on the driver.

 

Thanks again for your help.

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So the issue was too much bass in reference to the mid/treble output.  This is where voicing and E/Q come in.  An art of modifying the output to be balanced and smooth as required.

 

The change in the crossover will help minimize E/Q for a driver if the output is tailing off at that frequency.  Additionally changing the location of the crossovers will usually clean up the drivers output across the band if you are stressing the driver and pushing it to it's limits (or you are in a high distortion area) in that particular frequency range. In speaker voicing and design, everything is relative to each other.  Too much bass, too much treble, too in your face, that just indicates required eq.  Distortion many times indicates poor crossover locations or slope/Q.

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...what difference would it make if I crossed at 600 or 500?

 

Probably the only difference will be the bass bin polars - which narrow further at higher frequencies due to the dual mouths of the corner horn interacting with each other in the horizontal axis.  Other than that, you may not notice much difference.

 

Chris

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If you have any parametric EQ (PEQ) filters, I'd recommend placing one at ~3 kHz with a Q of about 0.7 and a gain of about -3 or perhaps a bit more.

 

Should add this before the crossover or after, as I have the option with the minidsp.

 

A shelf filter at about 6 kHz and a pretty big gain (6 or 12 dB/octave) will help.

 

Should this be a high shelf or a low shelf, i tried looking them up but was confused.

 

What I read about high shelf filters is that they boost signals above the cut off frequency.

 

From what I read I would want a high shelf,

 

Thanks for your help.

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I'd add the 3kHz, 0.7 Q, -3 dB PEQ on the output (HF channel) so as not to affect the LF, if you've got the extra PEQ there to use.  If not, then you can use the input side.

 

The shelf filter that I identified should be a high shelf. 

 

I can't really see the phase information on the plots.   Perhaps you can move it down a bit into the plot area and unwrap it using the "Controls" option on the right side of the graph, then center the 500 Hz phase region in the figure.  That will help you determine how much delay adjustment (if any) that you need.

 

Chris

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I'd add the 3kHz, 0.7 Q, -3 dB PEQ on the output (HF channel) so as not to affect the LF, if you've got the extra PEQ there to use. If not, then you can use the input side. The shelf filter that I identified should be a high shelf.

 

Cool, that is what I did.

 

I can't really see the phase information on the plots. Perhaps you can move it down a bit into the plot area and unwrap it using the "Controls" option on the right side of the graph, then center the 500 Hz phase region in the figure. That will help you determine how much delay adjustment (if any) that you need.

 

I should be able to do that,

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Here is the plot with the phase moved down using the scroll on the left side(db), and centered at 500hz with the phase unwrapped.  If I remember right the second plot is crossed over at 600 hz and should have the peq  high shelf filter you recommended.

post-27403-0-64960000-1439146565_thumb.j

post-27403-0-06400000-1439146658_thumb.j

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Phase looks good.  The FR between 350 Hz and 1 Khz may be candidates for attenuation (350-570) and boost (570-1K). 

 

I'd set the vertical frequency response scale on the REW graphs to no more than 5 dB per division, then it will be easy to see where to put the PEQs.  Sometimes  smoothing (1/48, 1/24, 1/12 octave) works for as long as you're adding or adjusting PEQs to see what you're trying to achieve.  However, I'm not a big fan of smoothing.

 

Looks good,

 

Chris

 

P.S., here is a table that converts from "Q" to bandwidth, courtesy of Rane:


Q	Bandwidth (Octaves)

0.5	2.54

0.55	2.35

0.6	2.19

0.65	2.04

0.667	2

0.7	1.92

0.75	1.8

0.8	1.7

0.85	1.61

0.9	1.53

0.95	1.46

1	1.39

1.1	1.27

1.2	1.17

1.3	1.08

1.4	1.01

1.414	1

1.5	0.945

1.6	0.888

1.7	0.837

1.8	0.792

1.9	0.751

2	0.714

2.15	0.667

2.5	0.573

2.87	0.5

3	0.479

3.5	0.411

4	0.36

4.32	0.333

4.5	0.32

5	0.288

5.5	0.262

6	0.24

6.5	0.222

7	0.206

7.5	0.192

8	0.18

8.5	0.17

8.65	0.167

9	0.16

9.5	0.152

10	0.144

15	0.096

20	0.072

25	0.058

30	0.048

35	0.041

40	0.036

45	0.032

50	0.029



Edited by Chris A
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