RS-P WWMTM 3 Way underway ( pic heavy )

[rpb]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

Yep.... If you select a larger portion of the graph, you can display the results on a 5 dB scale which will look better, and more like what you're used to seeing. Right clicking the mouse on the screen will probably do it.

Looks like the tweeter is padded a little more than needed.

[filmslayer]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

i really wrestled with tweeter padding . with two of them together in my small space it was a lil too bright ...

i can still see the mic start to shut down at 8k . knowing the 28f has a raising response i'm not too concerned but am gonna run a few sweeps using some of the suggestion mentioned above and see if i can find that top octave ...

[rpb]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

i really wrestled with tweeter padding . with two of them together in my small space it was a lil too bright ...

i can still see the mic start to shut down at 8k . knowing the 28f has a raising response i'm not too concerned but am gonna run a few sweeps using some of the suggestion mentioned above and see if i can find that top octave ...

If you have time, you can measure vertically off axis, and you should see a null at the x-over frequency, and some nulls due to the mtm arangement. It will look awful, but will show what is being directed toward the ceiling and floor. No need to post it. If you don't see a null at the tweeter x-over, further investigation is in order.

[filmslayer]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

If you have time, you can measure vertically off axis, and you should see a null at the x-over frequency, and some nulls due to the mtm arangement. It will look awful, but will show what is being directed toward the ceiling and floor. No need to post it. If you don't see a null at the tweeter x-over, further investigation is in order.

some more on how would be helpful ,45* above tweet axis ? got all day ! it is an absolutely beautiful day to be outside measuring a big speaker in Florida today ... the kind of weather that makes living through 6-7 months of near 100* heat and high humidity worth it !!!!

[rpb]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

i really wrestled with tweeter padding . with two of them together in my small space it was a lil too bright ...
...

Trust your ears! Measurements can help you determine if the treble brightness is up high around 12k, or lower around 2k, or somewhere in between.

[filmslayer]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

Trust your ears! Measurements can help you determine if the treble brightness is up high around 12k, or lower around 2k, or somewhere in between.

i do . Josh has taught me if it sounds right , it is !

[rpb]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

some more on how would be helpful ,45* above tweet axis ? got all day ! it is an absolutely beautiful day to be outside measuring a big speaker in Florida today ... the kind of weather that makes living through 6-7 months of near 100* heat and high humidity worth it !!!!

MTMs can sound different that TMs because of the reduced energy that bouces off the ceiling. That's due to the woofers (mids in your case) canceling each other at some frequencies due to different distances to the mic at 45 degrees. The tweeter and mids should also have a null at about 45 degrees due to the x-over. You may find it interesting to look at, that's all.

If you want, you could reverse polariy of the mids, or tweeter, and check for a null.

You're right about the weather. I'll be out for a bit enjoying it. Back later.

[filmslayer]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

i ran a sweep using 176k , slightly better but you can still see the 8k dip . setting up now for 45* vert .

[filmslayer]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

45* up ...




and 45* down ...





i have given up on the top octave ....

[rpb]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

Using the same measurements, switch the displays to gated.

[filmslayer]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

where do you wan to see them ?

[rpb]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

where do you wan to see them ?

On axis wiil look the same above about 300 hz. The vertical off axis will probably show more of a null. Look at the impulse to see how low you can set the gating. Probably about 250 hz.

Try taking some measurements from about 6' and see if anything changes. Might smooth out a little. Diffraction effects will vary with distance. If you measure about 10 degrees off axis to the side, it may change a little as well. Also measure approximately 30, 45, and 60 to the side. Just estimate the angle. This will tell you what is going to bounce off the side walls in your room.

[filmslayer]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

up 45* ..




down ...

[jbruner]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

I just saw the thread. The new measurement looks really good, but confirms what I was hearing. I'll send you the 200uf- 10 ohm zobel to correct the 220 hz peak on the woofer. The 25 or 30 ohm parallel resistor for excursion control on the mids will also smooth the knee at 1200-1500. Everything will install post-x-o, so it shouldn't be hard to add. We will change to the 1.2mH tap on the mid inductor. If we need to adjust the tweeter due to these minor changes, it will be less than 1/2 of a dB and will be done with a parallel resistor post-crossover also. I'll send you everything you need. I'm not seeing the drastic top-octave drop you had before. It doesn't look bad if you consider the scale- it's only 2dB down now, it was like 5dB before. Remember, I compensated for the rising response in the x-o already, so the most you should expect is flat. If the measured response is real-world and not a mic effect, we can just take a few turns off the 0.04mH coil. Not a priority right now.

[rpb]

Re: RS-P WWMTM 3 Way underway ( pic heavy )

That's strange. (The lack of a vertical null.)

If the x-over is accessisble, I'd disconnect the tweeter, and measure the mids. Then disconnect the mids, and woofer, and measure the tweeter. Then reverse the polarity of the tweeter. You should have a null vertically. Try about 30 degrees instead of 45. Somewhere there should be a null. It could be tilted higher or lower than 45 degrees. Knowing where it is will tell you a little about the tweeter and mid x-over.

What does the on axis phase look like? The impulse looks odd with the peak going downward. Try changing the entire speaker polarity at the amp, and remeasure. Then post the impulse. Lower the gating till it just almost touches the first reflection. Maybe below 250 hz. It should show in the impulse if you show a wider range on the chart.