That's only because you didn't design it to be 'flat'......... the basics of all audio speaker alignments are the same! Some just have more tuning flexibility than others, so more design considerations are required, ergo more ways to screw it up same as a buggy's beam axle suspension Vs a F1's complex articulated independent one.
GM
Low MMD won't show as a problem in Hornresp.
If you just look at frequency response and phase, the relatively low MMD Eminence 4015LF (8 ohm) seems to be the clear winner in the Keystone- same LF as the B&C 18SW115-4 ohm, costs a fraction, 3 dB more sensitive.
But the Hornresp sim or the frequency response don't give you an idea of what the driver sounds like at different levels, how one can sound fine at levels twice the rated power levels, another sounds OK with high power levels but has twice as much power compression, and another sounds so bad at high power levels (even though Xmax was not exceed) I did not bother to check the distortion.
But the most popular driver for TH here (until the cost went way up) was the 3015LF, which is a lightweight compared to the 4015LF.
Different strokes for different folks 🙂..
Art
Aaahhhh, my brain hurts!! Thanks Oliver, but I think I will have to file this info away for future use though, I am not quite there yet.
Hornresp's system design tool is based on the first paper. Hornresp will do all the math for you and give you an ideal reactance annulled full size front loaded horn for whatever bandwidth you choose.
What it will not do is give you any clue about how to use that info as GM does for tapped horns and other alignments.
What it will not do is give you any clue about how to use that info as GM does for tapped horns and other alignments.
Question of the Day - Driver XMAX vs. HR's Diaphragm Displacement
I have been reading through some of the other tapped horn design/build threads here this past week, and thanks to all the help many of you have given me, I think I am getting a deeper understanding of how these things work.
Here is my question for today. It seems to me that a drivers rated XMAX should not be exceeded - or you are asking for trouble. But in some of the designs I have been looking at, I see XMAX exceeded by 25%, sometimes even close to 50% when it is checked using HR's "Diaphragm Displacement" page. I have even seen people stating that it is alright to exceed XMAX.
I would appreciate a HR Brainiac response on this XMAX dilemma. Thank you.
I have been reading through some of the other tapped horn design/build threads here this past week, and thanks to all the help many of you have given me, I think I am getting a deeper understanding of how these things work.
Here is my question for today. It seems to me that a drivers rated XMAX should not be exceeded - or you are asking for trouble. But in some of the designs I have been looking at, I see XMAX exceeded by 25%, sometimes even close to 50% when it is checked using HR's "Diaphragm Displacement" page. I have even seen people stating that it is alright to exceed XMAX.
I would appreciate a HR Brainiac response on this XMAX dilemma. Thank you.
have a link to point at a specific sim? most people just show the unfiltered response/displacement (to avoid the extra copy and pasting), so the addition of the filter will help get the displacement in line, however filters dont do much for in band excursion maximas that exceed xmax.
Some woofers also have the "xvar" spec, which can exceed the xmax (the point where BL reaches 50 percent rated spec).
Some woofers also have the "xvar" spec, which can exceed the xmax (the point where BL reaches 50 percent rated spec).
Thanks for the comment sine143. The examples I am thinking about are all exceeding XMAX in the subs passband. There are quite a few of them I have come across, here are just a few I came across when searching again:
Here is an example where XMAX should be at 10:
http://www.diyaudio.com/forums/subwoofers/250573-alpine-sws-15d2-tapped-horn-3.html#post3807794
Here is an example where XMAX should be at 5:
http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge-190.html#post3278092
I have also seen numerous comments about it being O.K. to exceed XMAX in some of the older forum posts I have been reading. I can't remember what thread they were in, but they are definitely there.
So basically, are you agreeing with me that XMAX should not be exceeded (unless the XVAR spec is available)? Thank you.
Here is an example where XMAX should be at 10:
http://www.diyaudio.com/forums/subwoofers/250573-alpine-sws-15d2-tapped-horn-3.html#post3807794
Here is an example where XMAX should be at 5:
http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge-190.html#post3278092
I have also seen numerous comments about it being O.K. to exceed XMAX in some of the older forum posts I have been reading. I can't remember what thread they were in, but they are definitely there.
So basically, are you agreeing with me that XMAX should not be exceeded (unless the XVAR spec is available)? Thank you.
Xmax and how it is rated is a whole topic in itself. There are a few different ways driver manufacturers can come to an xmax spec. Some of these methods are more popular than others, and some are better than others at predicting when a driver is going to start sounding bad. Some manufacturers let the marketing dept make up a number for xmax and publish pure fantasy ratings. Some drivers sound ok at xmax, some start to sound bad well before they reach xmax, but not many drivers sound good past xmax.
In order for the xmax spec to be useful info you need to know how it was determined. Otherwise it's almost impossible to fairly compare drivers made by different companies. Sometimes you get lucky and there's published Klippel data but not usually.
Most people show their high power sims limited to the published xmax rating inside the passband and don't worry about exceeding xmax outside the passband, it's assumed that filters will take care of that. Front loaded horns are a bit different though. Their LF excursion starts to rise at a frequency above the LF knee and it's not always assumed that a HPF will take care of it; the hpf (if specified) is usually not at a high enough frequency to take care of the problem.
The power handling spec is very similar in that if you don't know how it was determined it really doesn't mean anything.
In order for the xmax spec to be useful info you need to know how it was determined. Otherwise it's almost impossible to fairly compare drivers made by different companies. Sometimes you get lucky and there's published Klippel data but not usually.
Most people show their high power sims limited to the published xmax rating inside the passband and don't worry about exceeding xmax outside the passband, it's assumed that filters will take care of that. Front loaded horns are a bit different though. Their LF excursion starts to rise at a frequency above the LF knee and it's not always assumed that a HPF will take care of it; the hpf (if specified) is usually not at a high enough frequency to take care of the problem.
The power handling spec is very similar in that if you don't know how it was determined it really doesn't mean anything.
Sometimes people get lazy and don't make the graphs perfect, sometimes they just want to see more spl.
I don't think xmax should ever be exceeded. Xvar is 50 percent down, it's going to sound pretty bad at that point. Most drivers will sound pretty bad well before they ever get to xmax.
Thanks for your input just a guy. I have been experimenting with some designs using low to mid priced drivers, and if I could safely exceed XMAX a bit, they might be workable. But I better not be tempted by the low prices - I guess you get what you pay for. Thanks.
- Status
- Not open for further replies.