I used two different measurement techniques to measure my builds. For the TLs ,I used a transfer function method (basically comparing it against the response of a known speaker in the same location). The method almost completely removes the "room effect" from the measurements. The measurements were done in my garage which is open on two sides.
EDIT - I forgot to mention that I also measure the impedance curves of my builds to see how well they match Hornresp's predictions.
EDIT - I forgot to mention that I also measure the impedance curves of my builds to see how well they match Hornresp's predictions.
Many drivers (car audio comes to mind) require such a small size cross-sectional area in TL (or you have no choice but to adapt to a larger size and then stuff it so that you don’t have the ridiculous peaks at the end of the band with) and it’s a compromise between that and the actual port velocity that would occur if you did size it ‘appropriately small’ and ignore that issue until you were stuck with listening to it….. noisy ports suck more than anything.
everything Martins math /Brian says is textbook/engineeer ‘perfect’ …. But in reality (sawdust and high output music) as soon as you make these things, and have to listen to them, or realize what it actually takes to put a variety of TS parameters to work in these there are areas which require a CSA/Length/ VAS compromise and stuffing in order to resolve the issues no matter what.
‘classic TL‘ still is useful in reality in many ways. Whatever ‘classic TL’ is?? 🥴
you dont have a choice but to stuff ‘oversize’ dimensions or sufffer the ‘peaks’ and ringing and one more or two note end points in a freq response that looks like Batman’s profile
or just go sealed/dsp and forget it all together? Nah… not as ‘diy’ fun for most
everything Martins math /Brian says is textbook/engineeer ‘perfect’ …. But in reality (sawdust and high output music) as soon as you make these things, and have to listen to them, or realize what it actually takes to put a variety of TS parameters to work in these there are areas which require a CSA/Length/ VAS compromise and stuffing in order to resolve the issues no matter what.
‘classic TL‘ still is useful in reality in many ways. Whatever ‘classic TL’ is?? 🥴
you dont have a choice but to stuff ‘oversize’ dimensions or sufffer the ‘peaks’ and ringing and one more or two note end points in a freq response that looks like Batman’s profile
or just go sealed/dsp and forget it all together? Nah… not as ‘diy’ fun for most
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Another minor update - I noticed a minor calculation error in the workbook that was causing it to incorrectly calculate the CSA in one section of the horn. I've addressed that in v1.6 of the workbook. I've included an expansion profile graph in the workbook so such errors can be more quickly identified in the future.
Putting the driver right at the bottom of the front panel does not completely eliminate the "blip" around 120 Hz, as can be seen in the Hornresp sim. The driver needs to be located further down the path to completely null out the 3rd harmonic and thereby flatten the response around 120 Hz. And I have an idea of how I might be able to accomplish that - by changing the design from a straight TL to a segmented one with slightly different CSAs for S1-S2 and S4-S5. I think this can be accomplished by shifting the panels highlighted below. I'm going to modify the workbook accordingly in the next day or two to see if that actually works. Yes, the picture shows S2 and S3 right on top of each other because of the location of the driver in this particular layout. S2 goes through the center of the driver and S3 is located at the bottom of indicated panel.
Yes, yes, I know it's a bit of lily-guiding, but if it can be done, why not do it? 🙂
I've contacted someone already about building the box for me. I suspect that my box-building days might be near over, due to a number of factors.
Putting the driver right at the bottom of the front panel does not completely eliminate the "blip" around 120 Hz, as can be seen in the Hornresp sim. The driver needs to be located further down the path to completely null out the 3rd harmonic and thereby flatten the response around 120 Hz. And I have an idea of how I might be able to accomplish that - by changing the design from a straight TL to a segmented one with slightly different CSAs for S1-S2 and S4-S5. I think this can be accomplished by shifting the panels highlighted below. I'm going to modify the workbook accordingly in the next day or two to see if that actually works. Yes, the picture shows S2 and S3 right on top of each other because of the location of the driver in this particular layout. S2 goes through the center of the driver and S3 is located at the bottom of indicated panel.
Yes, yes, I know it's a bit of lily-guiding, but if it can be done, why not do it? 🙂
I've contacted someone already about building the box for me. I suspect that my box-building days might be near over, due to a number of factors.
Brian
I don't mind the blip as I HP at 100
Where we can get metal grills for the cabinets
That's a pita to get.
I don't mind the blip as I HP at 100
Where we can get metal grills for the cabinets
That's a pita to get.
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Can l use two of such TL boxes, one above the other,? 8 ohm drivers connected in parallel so they can be connected to just one power amp. Above of them midrange enclosure and above compression tweeter with horn. A huge tower all in all. but why not a labirinth air escape? The upper air way just don't escape. TL should have a free air flow, no forced like a BR.
I think one cabinet next to each other will work better than a pile of them.
But better ask Brian, he's more versed in subsonic wizardry than me.🥳
But better ask Brian, he's more versed in subsonic wizardry than me.🥳
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Well then you can simply use a conventional entry at the high pressure end(closed end) for the entire 1/4 wave length instead ?
There’s No need for the offset entry at the 3 x 1/4 harmonics pressure node if that’s your intended bandwidth use/want/need? .
I use a sheet metal supplier but you have to order quite a lot at once. You could try wooden grills, the open area does not have to be a high % for subwoofer use.
One thing that I always love to see is the metal grills on commercial made cabinets , no matter if they are subs or tops , only time I don't see grills is like on the horns or BP's that have the driver not at sight (CV L36,EAW LA400,TS Milan 18)
Also the metal grill do some structural integrity to the horn mouth.
And withstand the rigors of the road when gigging with your mobile PA.
Haven't seen PP setup in a 2 way cabinet !!
What you mean by quite a lot ?
They cap the minimum buy by price ?
How much is that?
Also the metal grill do some structural integrity to the horn mouth.
And withstand the rigors of the road when gigging with your mobile PA.
Haven't seen PP setup in a 2 way cabinet !!
What you mean by quite a lot ?
They cap the minimum buy by price ?
How much is that?
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If you're in the UK*, speak to Markie at http://www.speakergrills.co.uk/steel.htm.
* to be fair, depending on your tolerance for shipping costs, he'd probably be willing to ship to Europe too.
Nope, it's definitely large-ish, big starts around 200 liters and crossing 300 liters is huge. 😁
Crossing 400 is like: you might as well sacrifice the basement to make full size bass horns instead of just going 401 liters because you will never lug it around anyway.
https://worlds-biggests.blogspot.com/2009/12/worlds-biggest-subwoofer.html?m=1
https://worlds-biggests.blogspot.com/2009/12/worlds-biggest-subwoofer.html?m=1
I tried the 201.1cm length with the JBL GX1200 and there is too big of a hump in the response. Here's a 9 footer.
