So many things wrong here -
1. A driver will not show a clear "whomp-up" at resonance in IB unless the driver qts is around 1 or higher, as I just showed.
2. Your measurement is not even a sealed box, it's closer to hybrid OB, which is entirely different so it obviously says nothing about IB response.
3. Your posted data doesn't even go down to 15 hz, it isn't showing anything "clearly" at 15 hz.
4. There's a bit of a bump at 22 hz, this could be anything from room resonances to eq or a dozen other things. Change the mic position and see if it's still there.
5. "No eq to speak of" isn't the same thing as no eq.
6. As I mentioned, none of the in room bass response measurements that you have posted of any of your various speakers are anywhere near typical so you either have massive gains (or standing waves) provided by the room or you are liberally using eq or something in your setup or measurements is very wrong.
Again, last week you were advocating the lowest possible q, now you are advocating a huge bump at resonance, which is exactly the opposite of low q.
The only way to get a huge bump at resonance in a sealed box is with very high qts drivers, which are generally very cheap and don't have much xmax or power handling.
As I've mentioned before, you can get just about whatever frequency response curve shape you want regardless of fs, but if you want a huge bump at 15 hz in a resonant box, the box has to be VERY large. This isn't a case of shooting for flat response, it's a case of getting the most you can with the space you can afford. Strict limits were placed on box size. If there were no limits you could have your big bump at 16 hz if that's what you wanted.
Since you seem to be challenging the designer here, can you show an example (simulated or measured OUTSIDE not in your concrete bunker little room) that shows how to achieve this big bump at 16 hz without increasing the box size?
Anyway, if the OP wants stronger 16 hz relative to higher frequencies, he's already mentioned he has at least a couple of different ways to eq whatever response curve he wants.
And again, the sim doesn't march anyone in any direction. Hornresp was used for this sim, and it doesn't recommend anything. All the values are user inputs, there's no predefined output unless you want to use the default horn example or use the System Design tool to design a full size front loaded horn. To make this very clear - the simulator had no input in the design other than calculating the user inputs.
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Ben,
A driver with a resonance at 15 Hz need not show a "whomp-up at 15 Hz in a near-infinite baffle", regardless of your point of view.
Your response curve simply shows your room/driver combination, and has little to do with the simulation which differs from your "point of view" of what should happen.
Art
I'm going to say this. It is MY OPINION.
I'm a big fan of "I statements". These are the ones where people express their own point of view. "I think that a yada yada is better than a dooby dooby. And here's why." They often come with supporting arguments or evidence. And they let people draw their own conclusions based on the soundness of the evidence. They are primarily focused on solutions - rather than being focused on personal issues.
There are people who are more prone to "You statements". Sometimes solutions do come from these statements. But the thrust also often has a "you're wrong" element to it. "Once again, you've missed the point." The underlying flavor of the advice of any possible proposed solution is usually at the expense of someone else.
I like to focus on "I statement" solutions. For one thing, I think they are more civil and promote allowing more people to feel safe offering their own ideas. I also think they tend to be a little more efficient.
I appreciate that most people here are seeking to come up with good solutions. Not everyone is going to agree. And some points of view may be accepted and others may fall by the wayside. And sometimes the best solution won't be the one selected. I think that is perfectly normal. But when we become more focused on who is right and wrong, there's more of a chance that someone will be needlessly hurt. And potential solutions - good and bad - often are slower in coming. Let people decide for themselves who is right and who is wrong. You don't have to put down someone else.
I'm not the moderator or administrator of this forum or of this thread. And I cannot make people post my way. All I can do is make I statements about what I like to see. And that is what I hope I have just done. I've said no names and made no accusations; I've just stated MY opinion and MY personal preference.
Just my two cents worth. And worth all it cost you.
Bach On
I'm a big fan of "I statements". These are the ones where people express their own point of view. "I think that a yada yada is better than a dooby dooby. And here's why." They often come with supporting arguments or evidence. And they let people draw their own conclusions based on the soundness of the evidence. They are primarily focused on solutions - rather than being focused on personal issues.
There are people who are more prone to "You statements". Sometimes solutions do come from these statements. But the thrust also often has a "you're wrong" element to it. "Once again, you've missed the point." The underlying flavor of the advice of any possible proposed solution is usually at the expense of someone else.
I like to focus on "I statement" solutions. For one thing, I think they are more civil and promote allowing more people to feel safe offering their own ideas. I also think they tend to be a little more efficient.
I appreciate that most people here are seeking to come up with good solutions. Not everyone is going to agree. And some points of view may be accepted and others may fall by the wayside. And sometimes the best solution won't be the one selected. I think that is perfectly normal. But when we become more focused on who is right and wrong, there's more of a chance that someone will be needlessly hurt. And potential solutions - good and bad - often are slower in coming. Let people decide for themselves who is right and who is wrong. You don't have to put down someone else.
I'm not the moderator or administrator of this forum or of this thread. And I cannot make people post my way. All I can do is make I statements about what I like to see. And that is what I hope I have just done. I've said no names and made no accusations; I've just stated MY opinion and MY personal preference.
Just my two cents worth. And worth all it cost you.
Bach On
Can we get an authoritative judgment from a recognized or credentialed expert about that one way or the other?
B.
^ JAG, for the love of (insert deities here), instead of simply claiming you have a better model, why don't you start a thread where you pontificate on that very fact and show model validation from measured impedance/spl plots. Then you can keep a link of it in your signature.
Or, alternatively, if it's a bit of IP you'd like to keep private, stop talking about it from the high heavens. It's gotten a bit old.
BenToronto--I don't honestly understand what you're objecting to and every one of your posts seems to try and reach some different conclusion. Either way, there seems to be a large breakdown in communication (your side or mine) that leaves me wondering if you're simply tilting at windmills (it's a common predilection in DIYAudio land).
Or, alternatively, if it's a bit of IP you'd like to keep private, stop talking about it from the high heavens. It's gotten a bit old.
BenToronto--I don't honestly understand what you're objecting to and every one of your posts seems to try and reach some different conclusion. Either way, there seems to be a large breakdown in communication (your side or mine) that leaves me wondering if you're simply tilting at windmills (it's a common predilection in DIYAudio land).
I've posted on it exhaustively since last October. Started at least 2 different threads in 2 different forums (including this forum). Posted at least a dozen examples of sims vs measurements, tweaked and non tweaked (my tweaked sims are exponentially more accurate). Gone into fine detail about how to do it and which drivers need it. There's literally hundreds of posts on this tweak, mostly at avsforum because there was literally no interest whatsover here. Not to mention the fact that I actually DID just tell you how to do it a couple of posts back.
If you want info ask for info. This attitude is pretty much exactly why these types of driver continue to be simulated less accurately than they could be.
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Fine, I'll leave this thread too.
For what it's worth, on a technical forum I don't think there should be very many subjective "I think" statements at all. I've provided tons of technical info in all of my posts. I think it's a great disservice to allow misinformation to go unchallenged. When I was a beginner I wasted a lot of time and money on trying to figure out who knew what they were talking about and which information to trust. If that's the path you want to take, muddling through misinformation in the name of civility, then it's going to be a tough journey. I can't be part of a discussion with equal parts unquestioned good and bad information, it's a waste of time.
And this is where Mark would come in saying "Pill time." And then we all have a good laugh. Good luck.
Thanks for the cordial and informative answer. It helps me understand the results of any sim concerning the HT18.
BO
You may have, and that's all well and dandy, but, if your posts are scattered to the wind (and they are), then it makes your point less cogent and entirely user antagonistic. As I said, it'd really be best if you park that in one location that you can cite directly. A little front-end work to curate your prior efforts might well save you a lot down the line (where you can simply say "have a look at this" rather than explaining something againandagainandagain). Take a page from jcx on his endorsements of composite amplifiers--he's very good about linking/citing to more in-depth articles/threads.
Apologies to Bach On for the tangents. 🙁 As your design stands, there doesn't seem to be much between the TH and the vented, which is unsurprising when you get to monster sizes. Does make you wonder if an ML-TL buys you any advantage (a variant of a purely vented alignment and a TL), given you certainly have the space to try to engineer the 1/4 wave in these large boxes.
I think you have provided a lot of useful information. I've found much of what you have to say interesting and valuable. I really see no need for anyone to leave. If you aren't happy, then do so. But I'm not trying to chase you or anyone away.
Is there no possible way to challenge misinformation without putting down the person who posted it?
I've found that many successful people in the workforce made it to the top by being able to express their creative and scientific ideas in a positive way. A dictatorship is possibly more efficient. But civility isn't always a waste of time - especially when you plan to work with a team of people over a long time. If I've got to put you down to get my ideas accepted, then maybe I need to try a different method.
Why not give us antique newbs a little credit for being able to weigh the data for ourselves and learn?
Take care.
BO
Hi Y'all,
I like to provide people w/ references to what I consider reliable information, and relevant discussions, so here are some more:
infinite baffle:
https://home.comcast.net/~infinitelybaffled/
sealed (the R.H. Small Closed-Box papers):
http://www.atps.net/notes/Closed-Box-Loudspeaker-Systems-Part-I-Analysis.pdf
http://cholla.mmto.org/speakers/theory/Closed-Box-Loudspeaker-Systems-Part-II-Synthesis.pdf
open baffles and dipoles (also Linkwitz Transform):
Linkwitz Lab - Loudspeaker Design
**********************************************
I'm not quite certain the SI HT18 falls under the category of drivers, that need to have adjustments made to their Bl or Re to arrive at correct simulations, and I'm not totally convinced, that this method will apply @ any power level, or mainly @ high power levels (which is obviously what we are looking @ here). For those interested I'll attach my notes/copies of the discussion, including a link to JAG's thread on the subject:
http://www.diyaudio.com/forums/subwoofers/264052-simulating-high-inductance-more-accurately-2.html
Regards,
P.S.: I just wanted to show one possible kind-a-horn-like way of using the SI HT18 for Bach On's winter project, I had and have no intention of taking over this thread. I have previously stated and shown, that the simulated results for regular vented boxes and T-TQWT will show similar SPL levels, and have given the reason(s) why I deem the T-TQWT superior in this application. I hope, that somebody will come up w/ some design that surpasses the still somewhat questionable simulation of the SI HT18 in T-TQWT#2.
I like to provide people w/ references to what I consider reliable information, and relevant discussions, so here are some more:
infinite baffle:
https://home.comcast.net/~infinitelybaffled/
sealed (the R.H. Small Closed-Box papers):
http://www.atps.net/notes/Closed-Box-Loudspeaker-Systems-Part-I-Analysis.pdf
http://cholla.mmto.org/speakers/theory/Closed-Box-Loudspeaker-Systems-Part-II-Synthesis.pdf
open baffles and dipoles (also Linkwitz Transform):
Linkwitz Lab - Loudspeaker Design
**********************************************
I'm not quite certain the SI HT18 falls under the category of drivers, that need to have adjustments made to their Bl or Re to arrive at correct simulations, and I'm not totally convinced, that this method will apply @ any power level, or mainly @ high power levels (which is obviously what we are looking @ here). For those interested I'll attach my notes/copies of the discussion, including a link to JAG's thread on the subject:
http://www.diyaudio.com/forums/subwoofers/264052-simulating-high-inductance-more-accurately-2.html
Regards,
P.S.: I just wanted to show one possible kind-a-horn-like way of using the SI HT18 for Bach On's winter project, I had and have no intention of taking over this thread. I have previously stated and shown, that the simulated results for regular vented boxes and T-TQWT will show similar SPL levels, and have given the reason(s) why I deem the T-TQWT superior in this application. I hope, that somebody will come up w/ some design that surpasses the still somewhat questionable simulation of the SI HT18 in T-TQWT#2.
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Originally Posted by weltersys
Ben,
A driver with a resonance at 15 Hz need not show a "whomp-up at 15 Hz in a near-infinite baffle"
I'd consider the speaker designers for Eminence, B&C, EV etc. to be experts.
Those companies, and many others mount speakers on a baffle on a wall to test what amounts to the response of a near-infinite baffle.
In none of the hundreds of response curves posted by these companies is any "whomp-up at free air resonance (fs) in a near-infinite baffle" evident.
Just as one example below you can see the response of an Eminence Lab 12, 22 Hz fs, there is no "whomp-up at free air resonance", just the usual low frequency fall off one expects to see in an infinite baffle.
At any rate, Bach On (like almost all those looking to achieve high SPL LF in large rooms) has already decided the drooping LF of a sealed cabinet won't get the job done.
Art
Ben,
A driver with a resonance at 15 Hz need not show a "whomp-up at 15 Hz in a near-infinite baffle"
Ben,
I'd consider the speaker designers for Eminence, B&C, EV etc. to be experts.
Those companies, and many others mount speakers on a baffle on a wall to test what amounts to the response of a near-infinite baffle.
In none of the hundreds of response curves posted by these companies is any "whomp-up at free air resonance (fs) in a near-infinite baffle" evident.
Just as one example below you can see the response of an Eminence Lab 12, 22 Hz fs, there is no "whomp-up at free air resonance", just the usual low frequency fall off one expects to see in an infinite baffle.
At any rate, Bach On (like almost all those looking to achieve high SPL LF in large rooms) has already decided the drooping LF of a sealed cabinet won't get the job done.
Art
Attachments
Everybody has their personal hangups. And I have more than my share. I did not want to chase anyone away from this thread. One of the things I tried to stress is that I value input from everyone. I just fear people may lurk and be reluctant to post an idea - that may or may not be good - if they are constantly fearful I'll attack their ideas and them.
It has been my experience over 66 years that most people really want to feel respected. I know I do.
I beg forgiveness of any and all participants I offended if I stepped out of line due to my personal whims. I fear I've hurt someone. And that was not my goal.
Bach On
It has been my experience over 66 years that most people really want to feel respected. I know I do.
I beg forgiveness of any and all participants I offended if I stepped out of line due to my personal whims. I fear I've hurt someone. And that was not my goal.
Bach On
@ just a guy
I posted a new thread with interest 🙂 about your Inductance findings etc. http://www.diyaudio.com/forums/subwoofers/275765-inductance-thread.html
@ tb46
Re your HR file TTQWT_2B.txt It's listed as a TTQWT but loads etc as a TH ?
I posted a new thread with interest 🙂 about your Inductance findings etc. http://www.diyaudio.com/forums/subwoofers/275765-inductance-thread.html
@ tb46
Re your HR file TTQWT_2B.txt It's listed as a TTQWT but loads etc as a TH ?
I'm not hurt, annoyed or frustrated with you, no need to be sorry. I just have a different idea about how misinformation should be treated, no hard feelings at all.
Yes, sorry, I shouldn't have said "zero interest here", but most of the in depth conversation did happen at avsforum, the discussions on this forum barely scratched the surface. There are links to the avs discussions in the link you provided though, I think. If not, it's mostly in the HzHorn thread at avs starting around page 8.
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