The graph at post #36 shows the LF 100 Hz or so decays in about half of the time frame, but from 200Hz upward until the tweeter Xover you have a very slow decay? I am guessing in matching Daves time you have picked up some reflected data. Even if this is the case it doesnt explain why the the drivers are taking so long to decay across so many frequencies.
I would need to look at the decay of one of the midrange drivers in isolation to help understand is it the driver, or reflections from within the cabinet coming out through the cone etc. Do you have any damping in there ? what does the decay look like at a sound level of 80dBs, is the decay more sensible from the midrange?
Just seen your picture of the cabinet damping, I wonder what some decent stuffing would do to the decay.
I would need to look at the decay of one of the midrange drivers in isolation to help understand is it the driver, or reflections from within the cabinet coming out through the cone etc. Do you have any damping in there ? what does the decay look like at a sound level of 80dBs, is the decay more sensible from the midrange?
Just seen your picture of the cabinet damping, I wonder what some decent stuffing would do to the decay.
i would imagine this configuration to have issues.
of course the issue may also be something else.
try taking out the tweeter and one woofer and building a test bookshelf speaker to see if the drivers or the crossover or the box tuning are the problem.
if the bookshelf works fine but array doesn't then it is the arraying itself that is likely the issue.
sometimes one frequency may sound wrong because other frequencies are wrong. in other words the lows may sound wrong because mids are wrong and vice versa. you can only know that it sounds wrong - without measurement you can't tell what the problem is.
but you can try different things like the bookshelf or the midrange and maybe you will stumble on the answer.
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As per above but stay in the current box... run only the treble and one bass, say the one under the horn, and measure that. Expand with the bass driver above the horn... measure, add 2 more... see what happens as the "line" expands down/upwards...
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YOu are catching room effects/boundaries in those long measurements. Need to be gated enough to avoid reflections.
Also the enclosures needs more damping material.
Arez and others have thoughts about long measurement's being polluted with reflections/room boundary affects. Very good point.
I am wondering if there is something in your measurement that needs some adjustment. If I take a measurement from the impulse and go out with the window to another 6-12mS I can get graphs that look somewhat like yours.
How are you, aside from wearing yourself out with speaker measurements ?
I am wondering if there is something in your measurement that needs some adjustment. If I take a measurement from the impulse and go out with the window to another 6-12mS I can get graphs that look somewhat like yours.
How are you, aside from wearing yourself out with speaker measurements ?
Does each driver have its own compartment? Whats the volume? What damping is used inside? Closed?
The upper and lower basses, are they OB or do they have an own/other compartment.
It looks OK from 200 ->
The big hump at 45Hz isn't helping... try to EQ that out... F:45,Q:4, G:-5dB
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The upper and lower basses, are they OB or do they have an own/other compartment.
It looks OK from 200 ->
The big hump at 45Hz isn't helping... try to EQ that out... F:45,Q:4, G:-5dB
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My body is pain-affected & very tired, right knee and my back are the worse.
Was helping a novis fried with building new bathroom floor yesterday, and that was to much for me.
So frustrating when your head want to do so much, but your body "isen´t there" (all my skills for nothing)
Will later today try to do some efforts on the diy linesource.
Kindly regards John
As I said earlier, I tested the speakers without the ports for 2 weeks. (before i cut the 4 ports holes)
Simulations in Winisd showed better responses in the 120-220 hz region, so thats why my planed speakerdesign had 4 ported woffers.
Is your opinion that my problem comes from " that i design the 4 woofers ported" ?
Anyway, my first change will be to lower the LP on woofers to ca 1100 hz 12 or 18 dB.
regards John
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When i evaluated EQ many years ago, i notice that changes i certain frequencies also made changes in other frequencies, like a "chainreaction"
I had also sinse about 1988 strived to have as few components in the signal chain as possible, because for me that showed differances when i shift speakers.
So i really can notice a bad or good speakerdesign, by THE speaker it self and not "the hole system"
OK. If you uncheck the "normalise" button in png2 post #54 - how does that look?
Your bass bins jump 13ms from your top at 100Hz - this is quite a lot.
Re EQ - a lot has happened since 88. With a DSP EQ you can vary the Q values and make adjustments with surgical precision. But as you run a 4 way (?) system it gets a bit more involved if you want to keep it active. An other option is to introduce a 2-channel EQ in the digital domain and alter the total.
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Your bass bins jump 13ms from your top at 100Hz - this is quite a lot.
Re EQ - a lot has happened since 88. With a DSP EQ you can vary the Q values and make adjustments with surgical precision. But as you run a 4 way (?) system it gets a bit more involved if you want to keep it active. An other option is to introduce a 2-channel EQ in the digital domain and alter the total.
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