Hello,
I've measured the gated response of a Fountek FW168 in a closed box (Bessel alignment) without crossover.
The baffle is narrowest as possible and all corners are chamfered by 2 cm.
The microphone is in the center of the room and at 1 meter of the source... this cone seems to have a good directivity above 3KHz...!
Is there any measurement problem ?
If there's not, wich crossover frequency will you choose with a textile dome ?
I've measured the gated response of a Fountek FW168 in a closed box (Bessel alignment) without crossover.
The baffle is narrowest as possible and all corners are chamfered by 2 cm.
The microphone is in the center of the room and at 1 meter of the source... this cone seems to have a good directivity above 3KHz...!
Is there any measurement problem ?
If there's not, wich crossover frequency will you choose with a textile dome ?
Why complicate things? Looks fine to me. Is the 7,5khz peak annoying you? Even off axis?
At most I'd personally just do 1st order xo at 7khz if I absolutely MUST have a tweeter there, play with polarity and distance.
... But I'd rather do a 250-500hz xo to a woofer to let the FR sing it's song unhindered. On a slightly wider baffle, Or maybe one on each sidewall? Would dampen vibration...
Last edited:
I misunderstood what type of driver this is. 2,5khz looks great.
I know that I'd personally react to the 400hz -5db dip. Would probably make a flatter, wider speaker to hang on the wall instead.
The amplitude and Phase will be corrected with equalizer APO, 80Hz seems a reasonable target to match the 18' subwoofer at 90 dB.
"It is practically impossible for a single radiator to cover the 20 Hz to 20 kHz audio frequency range at adequate sound pressure levels (SPL) and with wide dispersion off-axis. At a 50 Hz bass frequency, for example, it takes an air volume displacement of 214 cm3 to generate 90 dB SPL at 1 m distance from the source in free space. Take a typical 6.5 inch (132 mm effective) diameter driver and its cone would have to move 14 mm peak-to-peak linearly, which by far exceeds its excursion capability (Ref. 4)."
Crossovers
I must use a LR24 under 3 KHz, there is an huge peak of distortion at 7-8KHz...
Yes and yes, i think so too, 2500Hz seems the best choice (with a 3/4' tweeter)
Last edited:
I completely agree, did not look at the drivers datasheet until after the reply, and I misunderstood some basic things. I would still make a wider baffle to cope with the 400hz frequency dip.
Edit:
Why not make it less deep but wider and hang it on the wall like my previous suggestion?
For instance I've made speakers than fit on the windowsill before with good results. If space is at a premium then you only have to be creative.
Last edited:
The dips are not at the same place when i put the loudspeakers at their listening position (and that's why i've posted a limited frequency range on my first post
)They are designed flat and fixed on the wall to compensate some of the low Qt rolloff, enlarge the sweet spot and delay reflexions.
But i'm still thinking that a 3 KHz should be possible (60° added in red)
Last edited:
I perhaps must re perform the measurements with REW, but in ARTA the envelope was Ok.
... but on the interesting part of the FR (2K to 4K) it should not be critical IMHO.
I don't remember the exact value
around 5-6ms i'm not sure.I should really remeasure
If correctly gated it don't affect... but my first wall is at 0.71 meter.
Yep that is what I was getting at. The measurement can't be correct, but now we know the issue, no way to get 5-6ms of clean signal when the nearest boundary is only .71m away.
Last edited:
I'm sure that there is no reflexions
PS : the distance was 0.75m from the mic, 1.5m from the walls.
Last edited:
You are right, i use the squares of my parquet floor
and there was 4 squares of 12.5cm... the mic was at 50cm.The ceiling is at 250cm and the center of the loudspeaker at 125cm.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.