01-29-2024, 04:06 PM
(This post was last modified: 01-29-2024, 05:29 PM by forty5cal1911.
Edit Reason: I can't read apparently :)
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(01-24-2024, 10:05 PM)oomzay Wrote: (@TheOldPresbyope - Thanks for the tip - I hadn't scrolled down and seen the attachments - just looking in the widgets above the edit box!)
Below is my initial plot of the Linn Kaber Passive drives with original crossovers on axis at ~90cm (averaged L&R speakers).
For those that don't know about the Kabers they have 3 drives: Trebble, Mid and Bass. The Mid and Bass use identical drives. Manufacturer documents specify the xovers as 80Hz LR2 and 2800Hz LR4.
The plot is made with calibrated UMIK-1. Multiple measurements seemed surprisingly consistent - the 1/3 plots overlapped each other exactly for most of the active range. However there are lots of obstacles and reflective surfaces in the room so I will take better measurements outside when the sun next shines (but that could be months!).
So now the fun begins as I feel my way forward... Before I implement active xovers I want to understand if the passive ones really match expectations...
I don't think we can read much into the nulls at 100 & 200 Hz at this stage because as well as the hard floor in the room, the mic was on top of tall thin speaker with its back square to the speaker under test!!!
I was a little surprised how close the bass and mid are up to 100Hz because I always assumed they had different sized enclosures - but looking at this plot I now think the enclosures must be very similar.
I was most surprised by the -8dB drop at the mid-trebble x-over. Shouldn't that be closer to -6dB ideally?
Crossover experts please pile-in with your opinions!
Begin by measuring them very near field as in 1 meter directly on axis to remove room modes and reflections from the equation. I would also use a sweep vs pink noise and gate the measurement to 50 ms you may have to go a bit higher for the bass driver. Then re-post your FR plots. That should give a cleaner look and the drivers direct FR.
My apologies I overlooked the statement that you had measured pretty much near field. I would scrap their crossover design altogether. I would start at LR 4th order at 3k and LR 4th order at 300.
