I'm about to start testing my FAST build for the crossover design. The drivers are an 8" RS225-8 (in a TL), and a 2.6" Vifa TC9FD18-8 in a sealed box.
My problem is the drivers are 318mm (12.5") apart vertically.
I was going to do all my testing of both drivers at 2m distance, on the axis of the Vifa. But now I'm starting to question whether that testing setup would be suitable, given the distance apart of the drivers.
Any advice would be appreciated.
The speakers are for casual living room listening.
My problem is the drivers are 318mm (12.5") apart vertically.
I was going to do all my testing of both drivers at 2m distance, on the axis of the Vifa. But now I'm starting to question whether that testing setup would be suitable, given the distance apart of the drivers.
Any advice would be appreciated.
The speakers are for casual living room listening.
What aspect are you worried about? If it's the driver centres you could calculate the difference due to the measurement style and compare to the difference at your listening position and see whether it's worth worrying about.
If it is the power distribution, you'll want to take polar measurements, including after crossing.
If it is the power distribution, you'll want to take polar measurements, including after crossing.
I was only worried about being too far off axis of the RS225 if I stayed up level with the TC9FD when doing the horizontal testing.
At 2m on the TC9FD's axis, , I will be around 9 deg. above the RS225.
I hadn't really thought about extensive testing after the crossover was built - just maybe a simple on-axis test (don't want to disappoint myself 🙄 ).
Without being too pedantic I'd say that won't change enough to really affect your crossover endeavour. (It may show things up at high frequencies beyond the cross, but measuring the high frequency performance of fullrange drivers is a story on its own 😉 )
This is my TL design (bloody lot taller than I imagined).
The space underneath the TL outlet is where the crossover will be located.
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Yes, designed by xrk971 https://www.diyaudio.com/community/threads/10f-8424-rs225-8-fast-waw-ref-monitor.273524/page-99
But the enclosure design didn't seem to work when put into Hornresp, and didn't seem to comply with the design theories of people like Martin King.
Regardless, I took the basic concept of combining the RS225 with the Vifa TC9FD, and did my own design using Hornresp. In hindsight, I don't think they are a very good match - RS225 is more sensitive than the smaller TC9FD.
I'm up to the measurements stage (hopefully tonight) before I begin my VituixCAD adventure.
From memory I think the Scan-Speak and TC9 were the same sensitivity? Could well be wrong.
You could see how the Vifa TG-9 (fibreglass, 4 ohm driver) or TC-7 (4 ohm, 2" driver) might sim with the RS225. Either might give you the sensitivity you're after.
The TC-7 with the RS225-4 in a MLTL won the 'best under $200' category in a 2013 US speaker competition.
Geoff
You could see how the Vifa TG-9 (fibreglass, 4 ohm driver) or TC-7 (4 ohm, 2" driver) might sim with the RS225. Either might give you the sensitivity you're after.
The TC-7 with the RS225-4 in a MLTL won the 'best under $200' category in a 2013 US speaker competition.
Geoff
I'm too far into this build now, but at least I probably won't be applying a L-pad to the TC9.
BTW the RS225-8 is a Dayton Audio.
BTW the RS225-8 is a Dayton Audio.
The RS225 is very highly regarded, used in many projects; wish I had a couple!
I assume that the woofer's output will be reduced by the Baffle Step Compensation which is built into the design.
Geoff
Hi Geoff
Actually I bought the RS225s from WES Australia https://www.wes.com.au/
They are really a wholesaler, but I still had my ABN from my business (I'm now retired), and I used that to start an account.
I intend to buy all my crossover bits from them.
Don't fret 😉 It's nice and flat and so easy to cross adequately.. so naturally it would score high reviews when used that way.
However for those who will put in the crossover work, you could do as well or better using other drivers.
Now that Dayton Audio prices in Oz have gone through the roof - I think the RS225 is now $180? - there's a lot of competition. The SB20PFC, for example: $60 and very similar specs.
Geoff