Hey Team. Long time no post.
I have recently moved house to a smaller listening room and a I really dont have the space to setup my Stereo Eminence Delta 15 LFA OBH-Baffles....
So I'm thinking of putting the 15's in QWTL cabs just for a bit of fun and the "I haven't heard large PA drivers in TL's before" factor which may or may not be worthwhile.... So before I make the sawdust I thought I would develop a design here and see if its viable.
This is also an opportunity to learn Hornresp which I have been really keen to do for a few years so I would like to keep the focus on that software.
Screenshots to follow....
I have recently moved house to a smaller listening room and a I really dont have the space to setup my Stereo Eminence Delta 15 LFA OBH-Baffles....
So I'm thinking of putting the 15's in QWTL cabs just for a bit of fun and the "I haven't heard large PA drivers in TL's before" factor which may or may not be worthwhile.... So before I make the sawdust I thought I would develop a design here and see if its viable.
This is also an opportunity to learn Hornresp which I have been really keen to do for a few years so I would like to keep the focus on that software.
Screenshots to follow....
15 LFA Data Sheet and my v1 Hornresp screenshots + system export.
1. I found and used Patrick's rough guide here :An Improved Transmission Line Alignment. to do a basic setup.
2. I dont claim to have followed it correctly!
3. As you can see f3 is approx 50hz for some or many reasons, see #2
4. I have set DO to 1/3 cab length
5. I have set S1 to driver SD
6. Taper set to 1/4
6. All input welcome... have at it
1. I found and used Patrick's rough guide here :An Improved Transmission Line Alignment. to do a basic setup.
2. I dont claim to have followed it correctly!
3. As you can see f3 is approx 50hz for some or many reasons, see #2
4. I have set DO to 1/3 cab length
5. I have set S1 to driver SD
6. Taper set to 1/4
6. All input welcome... have at it
Attachments
Looks to me like you could do with more gain towards the bottom of the passband for a flat response. Try doubling the cross-sectional areas and see what that gets you.
Chris
Chris
FWIW, tuning < ~0.707*Fs is not a good plan unless you're sure there's lots of room gain to protect the drivers and if using a hi-pass, not much point in doing it anyway.
Based on published specs, a grand piano's 27.5 Hz low note is a good XO point limit and still allows some significant bass output from pipe organs, etc., so recommend not exceeding it.
That said, doing a quick 'classic' vented alignment to get a baseline for further study: Vb = ~ 241 L/1.44 = ~167.36 L tuned to Fs = ~39 Hz with an Av = ~ 873 cm^2/3 = 291 cm^2 terminus conveniently works out to my preferred 10:1 CR. ;)
Note that such high CRs puts the driver at mid point or a little lower in more extreme tapers, though L* 0.5 is plenty 'close enough' once damped.
The sim looks good enough for me as is, but if you want to tune lower just tack on a straight or expanding duct vent.
Damp to 'taste'. ;)
Ideally though, this driver wants to 'feel' a much larger cab due to its relatively high Vas and especially its Qts, which of course would fill in the LF to better blend with the room gain unless either extremely small and/or these will be corner loaded.
GM
Based on published specs, a grand piano's 27.5 Hz low note is a good XO point limit and still allows some significant bass output from pipe organs, etc., so recommend not exceeding it.
That said, doing a quick 'classic' vented alignment to get a baseline for further study: Vb = ~ 241 L/1.44 = ~167.36 L tuned to Fs = ~39 Hz with an Av = ~ 873 cm^2/3 = 291 cm^2 terminus conveniently works out to my preferred 10:1 CR. ;)
Note that such high CRs puts the driver at mid point or a little lower in more extreme tapers, though L* 0.5 is plenty 'close enough' once damped.
The sim looks good enough for me as is, but if you want to tune lower just tack on a straight or expanding duct vent.
Damp to 'taste'. ;)
Ideally though, this driver wants to 'feel' a much larger cab due to its relatively high Vas and especially its Qts, which of course would fill in the LF to better blend with the room gain unless either extremely small and/or these will be corner loaded.
GM
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""That said, doing a quick 'classic' vented alignment to get a baseline for further study: Vb = ~ 241 L/1.44 = ~167.36 L tuned to Fs = ~39 Hz with an Av = ~ 873 cm^2/3 = 291 cm^2 terminus conveniently works out to my preferred 10:1 CR""
1. Is 1.44 our chosen system Q?
2. Is Av = SoS (Speed Of Sound) / Fs?
3. Why are we dividing Av by 3? Is that 3 line segments?
4. Is CR = Compression Ratio?
""Note that such high CRs puts the driver at mid point or a little lower in more extreme tapers, though L* 0.5 is plenty 'close enough' once damped""
5. Does L*0.5 = The driver being offset half way down the line.
Cheers again
Dean
1. Is 1.44 our chosen system Q?
2. Is Av = SoS (Speed Of Sound) / Fs?
3. Why are we dividing Av by 3? Is that 3 line segments?
4. Is CR = Compression Ratio?
""Note that such high CRs puts the driver at mid point or a little lower in more extreme tapers, though L* 0.5 is plenty 'close enough' once damped""
5. Does L*0.5 = The driver being offset half way down the line.
Cheers again
Dean
No, it has nothing to do with sysQ, it's strictly an optimum box compliance for a given Vas, so with modern day low Vas spec drivers it's often under-damped to some degree by T/S theory except always tuned to Fs, making it what some folks describe as a 'toe-tappin' musical performer.
Av - vent [terminus] area [S3].
Av needs to be large enough to keep vent [pipe] mach speed < ~17 m/s, which for average xmax drivers and/or stuffed pipes is ~1/3 Sd.
Correct, though in retrospect I should have used 10:1 'taper' since this is an offset driver pipe where the driver : pipe area at the offset [Sd/S2] is only 0.43:1.
Correct as shown in the sim I posted for you to Import into HR, so you can see the entire file to save, modify, use as a TQWT master.
GM
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Thanks GM for the clear answers and also for going the extra mile to do a sim!
To be honest I dont have enough experience with the software or system design to make any changes to your sim and really get the trade offs.
So before I go ahead and build something directly from your sim is there anything I could consider first?
Cheers again
To be honest I dont have enough experience with the software or system design to make any changes to your sim and really get the trade offs.
So before I go ahead and build something directly from your sim is there anything I could consider first?
Cheers again
You're welcome!
Dunno, I mean if you're happy with its simmed response like I am, then it's just a matter of whether to fold it or ??? You haven't provided any room, etc., details/plans or what they will mate to, XO details, etc..
GM
Dunno, I mean if you're happy with its simmed response like I am, then it's just a matter of whether to fold it or ??? You haven't provided any room, etc., details/plans or what they will mate to, XO details, etc..
GM
Hey bjorno.
I appreciate the input even though some or most of it is over my head.
I will spend some time researching it and report back.
Cheers all.
I appreciate the input even though some or most of it is over my head.
I will spend some time researching it and report back.
Cheers all.
