I want to use 1st order crossover, 2nd order only if its a MUST.
For the tweeter i selected planar GRS PT6816-8 8" open back , which plays down to 400Hz and from there roll-off starts. However, at 400Hz there is about +6dB peak comparing to 500Hz- 3,000 Hz range when it plays at 90dB.
At 300Hz, it outputs 87dB, but at 250Hz only 80dB
From 3,000hz it rises steadily up to 100dB........ Driver is rated at 94dB
My question is, can I cross it to woofer at 1,000 Hz? With first order?
Books say, the driver must play 2 octaves outside of such X-over.
I dont intend to play music very loud or even loud. Room is of avg size for a living room.
By the way, if I match it with 15 inch bass-mid woofer, is it OK with cross @ 1,000Hz? 15inch is rather large.....
But, I've seen speakers with 18inch woofer crossed at 700Hz, so i guess its ok?
Thanks
Any suggestions welcome.
For the tweeter i selected planar GRS PT6816-8 8" open back , which plays down to 400Hz and from there roll-off starts. However, at 400Hz there is about +6dB peak comparing to 500Hz- 3,000 Hz range when it plays at 90dB.
At 300Hz, it outputs 87dB, but at 250Hz only 80dB
From 3,000hz it rises steadily up to 100dB........ Driver is rated at 94dB
My question is, can I cross it to woofer at 1,000 Hz? With first order?
Books say, the driver must play 2 octaves outside of such X-over.
I dont intend to play music very loud or even loud. Room is of avg size for a living room.
By the way, if I match it with 15 inch bass-mid woofer, is it OK with cross @ 1,000Hz? 15inch is rather large.....
But, I've seen speakers with 18inch woofer crossed at 700Hz, so i guess its ok?
Thanks
Any suggestions welcome.
A lot of this depends on what performance aspects you find important.
For a first order crossover to integrate properly as a first order, you do need quite a bit of flat acoustic response for both drivers around the cross point before the crossover is applied. If you're OK with a higher order acoustic result, the natural midrange/tweeter roll-off can be combined with a first-order electrical filter to produce a steeper combined roll-off. The woofer crossover would then need to be compensated to match this in some way.
You didn't say whether the midrange and woofer are going to be dipoles, monopoles, a mix, or what. If both are monopoles, you will have some directivity mismatch around the crossover because the widths are so different between the two drivers. The extent will depend on the woofer's off-axis response. You may also have other design criteria you find more important. And obviously if anything is running dipole, it's a different deal.
Many 15-inch woofers have breakup modes around/beyond 1 kHz, which can make a shallow crossover there more challenging. You should keep an eye out for this behavior when choosing a woofer.
For a first order crossover to integrate properly as a first order, you do need quite a bit of flat acoustic response for both drivers around the cross point before the crossover is applied. If you're OK with a higher order acoustic result, the natural midrange/tweeter roll-off can be combined with a first-order electrical filter to produce a steeper combined roll-off. The woofer crossover would then need to be compensated to match this in some way.
You didn't say whether the midrange and woofer are going to be dipoles, monopoles, a mix, or what. If both are monopoles, you will have some directivity mismatch around the crossover because the widths are so different between the two drivers. The extent will depend on the woofer's off-axis response. You may also have other design criteria you find more important. And obviously if anything is running dipole, it's a different deal.
Many 15-inch woofers have breakup modes around/beyond 1 kHz, which can make a shallow crossover there more challenging. You should keep an eye out for this behavior when choosing a woofer.
Thanks. Tweeter will be dipole. Woofer - in downward firing basshorn.
Woofer can play to 3-4kHz, so i think no problems there. My worry is this planar tweeter.
I mean , in 2way, designers often cross dome tweeters which are Fs rated at about 1,500Hz, anywhere from 2,000-3,000Hz, with 2nd order.
So I guess driver with Fs of about 300Hz, is good @ 1,000Hz , first order?
Similar concept, Wolf von Langa SON, with AMT tweeter, is crossed at 800Hz.
Of course making it 3-way with some 6 ich mid / full range , and x-over at approx 400Hz + 3,500hz would solve this issue for sure.
But with such config I will have
The other concern I have is whether 15inch woofer in a basshorn will produce TOO MUCH bass in 450 sqft / 40 m2 room /10ft ceilings?
If it can, I would rather go Open baffle, but then again, i suspect single 15 inch per side will be a bit too weak....
And two such woofers per side, means much more costs.
Woofer can play to 3-4kHz, so i think no problems there. My worry is this planar tweeter.
I mean , in 2way, designers often cross dome tweeters which are Fs rated at about 1,500Hz, anywhere from 2,000-3,000Hz, with 2nd order.
So I guess driver with Fs of about 300Hz, is good @ 1,000Hz , first order?
Similar concept, Wolf von Langa SON, with AMT tweeter, is crossed at 800Hz.
Of course making it 3-way with some 6 ich mid / full range , and x-over at approx 400Hz + 3,500hz would solve this issue for sure.
But with such config I will have
- between 1kHz to 3.5Khz more heavy cone driver (Vs planar)
- in the freq. range of this mid , most likely lower sensitivity, as 15 inch woofer with planar will have at least 94dB.
The other concern I have is whether 15inch woofer in a basshorn will produce TOO MUCH bass in 450 sqft / 40 m2 room /10ft ceilings?
If it can, I would rather go Open baffle, but then again, i suspect single 15 inch per side will be a bit too weak....
And two such woofers per side, means much more costs.
No idea how much power this one can handle and output is what I'd be concerned about.
Why first order?
You can always turn it down (what am I missing?)
I feel like I should emphasise here that what Allen has displayed is a 1st order acoustic crossover centred at 1kHz. As you can see it needed a 2nd order electrical high-pass filter to arrive at this slope. This was necessary because of the tweeters rising response. The series pass inductor is used to tame the rising top end. I am not sure if Allen's crossover takes into account the tweeters full impedance although it could do as PE provide zma files too. I would have thought it may have required a notch to flatten the impedance peak but maybe not.
Allen's filter is beneficial because it provides a first order roll off during the region where the tweeter provides useful output but as it's actually 2nd order it'll provide much better control of what happens below this range.
As to if the tweeter will work this low? Distortion measurements with an appropriate filter, at your kind of listening levels, are the only true way to tell. Nevertheless you are considering operating the tweeter at 1kHz. I wouldn't want to go any bigger than 12" to keep the horizontal off axis good.