Hi,
WinISD illustrates the basic maths, not wrong, but not
accurate. I'd use Unibox to crosscheck any assumptions.
Generally for a front mounted driver and a side bass unit the front
is eq'd for bsc and crossed over to the side pretty low, its very
different to a wide baffle and bass also front and the x/o for that.
Trying to use a sidemounted unit for BSC of the main
unit is asking for a lot of real trouble and grief IMO.
rgds, sreten.
WinISD illustrates the basic maths, not wrong, but not
accurate. I'd use Unibox to crosscheck any assumptions.
Generally for a front mounted driver and a side bass unit the front
is eq'd for bsc and crossed over to the side pretty low, its very
different to a wide baffle and bass also front and the x/o for that.
Trying to use a sidemounted unit for BSC of the main
unit is asking for a lot of real trouble and grief IMO.
rgds, sreten.
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We covered that on page one Sreten. That's why he's gonna cross low and use eq to combat baffle step with the front mounted full range driver. 🙂
Hi,
Fair comment and something I want to look at. I wont be building anything until early in the new year so plenty of time to explore different options. Ultimately, it'll be down to if I can build the resulting enclosure 🙂
Easiest option for me is a basic enclosure and use DSP to help out.
Paul
Fair comment and something I want to look at. I wont be building anything until early in the new year so plenty of time to explore different options. Ultimately, it'll be down to if I can build the resulting enclosure 🙂
Easiest option for me is a basic enclosure and use DSP to help out.
Paul
I'm not so sure that the different baffle-step frequencies will be much of a problem.
Given that you're going for active crossovers, it'd be fairly trivial to implement a BSC filter for each driver individually, and then, with the resultant frequency responses, cross over where you like.
FAST systems are great because you take a full-range driver, and then take away all the cone excursion that 200Hz and below produces. Crossing over at 100Hz will still be beneficial, but, IMO, not as much as a higher XO point: snare drums (for example) have plenty of content in the 100-500Hz range, so you'll still get not-inconsiderable cone excursion from your FR unit.
FWIW, I tried a similar system (actually a portable boombox) with 3" KEF coaxials crossed at 600Hz, 2nd order. They still moved a couple of mm p/p on a loud snare drum.
Chris
PS - adding BSC to the FR unit will increase power where cone excursion is most likely. I'd argue this (to some extent) defeats the point of going FAST.
Given that you're going for active crossovers, it'd be fairly trivial to implement a BSC filter for each driver individually, and then, with the resultant frequency responses, cross over where you like.
FAST systems are great because you take a full-range driver, and then take away all the cone excursion that 200Hz and below produces. Crossing over at 100Hz will still be beneficial, but, IMO, not as much as a higher XO point: snare drums (for example) have plenty of content in the 100-500Hz range, so you'll still get not-inconsiderable cone excursion from your FR unit.
FWIW, I tried a similar system (actually a portable boombox) with 3" KEF coaxials crossed at 600Hz, 2nd order. They still moved a couple of mm p/p on a loud snare drum.
Chris
PS - adding BSC to the FR unit will increase power where cone excursion is most likely. I'd argue this (to some extent) defeats the point of going FAST.
Chris, if he crosses higher, the radiation pattern of the woofer will become a problem. Not so much the different baffle step points. The baffle step points are a resulting issue.
This is really the type of speaker you need to build, setup in your room, listen to and tweak. Personally, I'd build the top separate from the bottom to be able to position the woofer forward or sideways to make sure to get the best sound. Perhaps you can mock up a top and bottom (not intended for finishing) and play around before building the finished design? You may find no difference in sound if the woofer is sideways or forward facing. If you do hear a difference you can modify the design. Perhaps you can save money on purchasing two woofers and do a sub/sat system?
Just suggestions. If you get hooked on speaker building this won't be your last project because you will realize there are so many (too many) different kinds of speakers and become curious about obtaining different levels of performance offered by the different types of designs.
Just suggestions. If you get hooked on speaker building this won't be your last project because you will realize there are so many (too many) different kinds of speakers and become curious about obtaining different levels of performance offered by the different types of designs.
Tysen XOed at 330 Hz, Facets at 240 Hz, both with side woofers. For A7, 160 Hz seems about right
dave
dave
Hi,
FWIW a 100Hz x/o point is too low for a small FR.
200Hz L/R acoustic is a lot more more like it to allow
the bass unit to relieve the FR of major excursion issues.
rgds, sreten.
FWIW a 100Hz x/o point is too low for a small FR.
200Hz L/R acoustic is a lot more more like it to allow
the bass unit to relieve the FR of major excursion issues.
rgds, sreten.
How wide were the baffles? I bet it made the polar response uneven. But maybe it didn't matter... Especially in your room with the left side open. Who knows, maybe it's a good thing to keep the sound off the side walls. More sound on the rear walls though. I wonder...
Yes, but if it screws up the polar response. Lesser of two evils I guess.
Looks like we have a smartie pants on our hands 😀 Good post. The whole thing. Low XO'ers really are room dependant.
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That's a pretty wide baffle. I wouldn't be so sure. Probably fairly half space by 150hz. Maybe not fully, but half way there. I recently measure a 13" baffle to be fully half space by 600hz iirc. This looks bigger. But 200hz might not be to big of deal and definitely worth trying.
Hi guys and thanks all for the responses ...
I'd previously thought about separate enclosures for the FR & woofer. Apart from being able to face them in different directions I wouldn't have much space to play about with placement within the room. So, two drivers in one cabinet.
After reading your comments, I realised two things; 1, The side mounted woofer isn't the best way forward. 2, Unintentionally, I'd got my thinking the wrong way round regarding the use of the woofer. I wanted to get a higher XO point, offloading some of the work to the woofer. Instead I was forcing myself to use a lower XO, gaining little.
Didn't fully appreciate that the woofer acts as the BSC ...
So switching tacks... Both drivers on the front baffle, same sealed box volumes [6.41L & 70.64L] and aim for an XO around 250 ~ 300Hz. Again, it'll be active XO & EQ.
Will load a sketchup when the add attachment & my internet connection allows it 🙁
I'd previously thought about separate enclosures for the FR & woofer. Apart from being able to face them in different directions I wouldn't have much space to play about with placement within the room. So, two drivers in one cabinet.
After reading your comments, I realised two things; 1, The side mounted woofer isn't the best way forward. 2, Unintentionally, I'd got my thinking the wrong way round regarding the use of the woofer. I wanted to get a higher XO point, offloading some of the work to the woofer. Instead I was forcing myself to use a lower XO, gaining little.
Didn't fully appreciate that the woofer acts as the BSC ...
So switching tacks... Both drivers on the front baffle, same sealed box volumes [6.41L & 70.64L] and aim for an XO around 250 ~ 300Hz. Again, it'll be active XO & EQ.
Will load a sketchup when the add attachment & my internet connection allows it 🙁
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Apologies for side-tracking this thread, but I have a question that probably doesn't warrant a separate thread:
Does the term FAST only apply to a full-range driver in a larger cabinet, with a helper woofer in the same cabinet, or can it also be applied to small full range speakers with an external subwoofer, i.e. a sub/sat configuration?
Does the term FAST only apply to a full-range driver in a larger cabinet, with a helper woofer in the same cabinet, or can it also be applied to small full range speakers with an external subwoofer, i.e. a sub/sat configuration?
Not a problem Howard. The more questions we ask, the more we learn and our understanding improves 🙂
Studio Au; Hi, all ready had a good read through your thread. I like the idea of the teardrop enclosure, unfortunately way beyond my build skill level 🙂
I may buy the drivers for this sooner rather than latter, the woofers have just been reduced in price from €99 to €82 each. Plus a pair of A7.3 and a 4' x 8' of 18mm B/B ply.
Paul
Studio Au; Hi, all ready had a good read through your thread. I like the idea of the teardrop enclosure, unfortunately way beyond my build skill level 🙂
I may buy the drivers for this sooner rather than latter, the woofers have just been reduced in price from €99 to €82 each. Plus a pair of A7.3 and a 4' x 8' of 18mm B/B ply.
Paul
Brief Update
It gets pretty boring saving money, loads of ideas but just have to be patient and wait... Plus prioritising which bits & pieces to get first.
Seen a few tantalising bits about the new FHXL and can imagine them to be amazing sounding speakers, but think this route may be more suitable to my needs.
Whilst waiting I've been playing with Sketch Up a little more and thought it'd be nice to see how the proposed enclosures would sit in my room ...
Paul
It gets pretty boring saving money, loads of ideas but just have to be patient and wait... Plus prioritising which bits & pieces to get first.
Seen a few tantalising bits about the new FHXL and can imagine them to be amazing sounding speakers, but think this route may be more suitable to my needs.
Whilst waiting I've been playing with Sketch Up a little more and thought it'd be nice to see how the proposed enclosures would sit in my room ...
Paul
