No, not conical. I thought you said you had one? Any cheap WGs that fit his criteria other than the 8" and 12" of the same family? If so that's news to me. I know they just came out with one that looks like the JBL Zilch used to employ for EW duty, but we know his feelings on those. There are also the elliptical WGs of the same family, but again....
You have seen his designs. Right?
Dan
Soongsc, can you explain that a bit? I'm not sure what parital apects are. Can you also explain why these types of drivers will perform badly at low levels (I assume you mean softer cones)? That's a first for me.
Thanks,
Dan
I was hoping that seeing stored energy on axis, or lack there of would correlate with off axis performance since no one does off axis measurements far enough to know wether or not the driver is going to give you fits. It was a hope that turned out not to be true, but I found something that didn't work.😀 I'm thinking that they're all going to give you fits at this point, but hoping to be wrong. I haven't seen anything yet that would lead me to believe otherwise. I am wondering if heavier cones might be better. The Summas use heavy cones and have great off axis performance. I want to see some info so bad on this aspect of loudspeaker design it ain't funny. Driver break up behavior is far more problematic well off axis. Are there any drivers known to have excellent far off axis performance?
I never was--Just hoping for a correlation. IOW, grabbing at straws out of desperation in hopes to be able to buy drivers based on something more than a guess. My new best guess is heavy(ish) cones.
Any evidence it equates to SQ? That would be cool to see as well b/c I haven't yet. I do know that it measures the resonances we have more trouble hearing. Even you don't use your best driver in this regard. I'd believe it was an identifiable factor if there were evidence as it seems reasonable to some degree, but as of right now it's a minor issue to me. Soongsc has a cool theory on it--the best I've heard of.
I'd admit that I would avoid something like this courtesy of http://www.zaphaudio.com/6.5test/compare.html:
But that's only out of paranoia as it just looks bad.
Are you sure this isn't a p$$ng contest? 🙄 Sounds like one. Show me actual graphs to 90 degrees and let me know how you got there? It would save me a lot of trouble and revolutionize DIY speaker building. What driver characteristics lead to good off axis performance? It would be nice if any of you guys would help the rest of DIY. Thing is, just days ago you didn't think anything beyond 45 degrees was even necessary, but that's where the trouble lies--beyond 45 and mostly it seems in the 60, 70, and 80 degree range with the paper cones I have. 90 WGs will be easier for sure as they'll allow for lower crossing. That's one helpful point. Never doubted that, but I would prefer to get narrower so I can avoid more Very Early Reflections. It may well not be worth the fight. It would be great to turn this into a measurements thread--when, what, how, and why?😀
See my graphs and the lengthy discussion we had when you didn't want to believe the evidence then later conceded. That to me is the hard part.
I mentioned that already. They're just like any other FR graph only at various axis. It's the RS100-8 and it's off axis response is actually very bad. at 33.75 off axis, it's already terrible.
Dan
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Looking at CSD data, if it decays fast, it is an indication of clean sound. However, it cannot show you why it decays fast.
I normally compare at two time scales in SoundEasy, the shortest time, and something close to 4ms scale. Different drivers will decay differently, thus the sound balance is different, and the timbre is also different. When softer material is used, the VC former is pushing gainst soft material, and some energy is lost due to friction nature in the material, yet if you look at the 0.4ms time range, it may not show fast decay in the initial part of the decay, this is due to the springy nature of the soft material which causes delayed release of energy it stores.
I normally compare at two time scales in SoundEasy, the shortest time, and something close to 4ms scale. Different drivers will decay differently, thus the sound balance is different, and the timbre is also different. When softer material is used, the VC former is pushing gainst soft material, and some energy is lost due to friction nature in the material, yet if you look at the 0.4ms time range, it may not show fast decay in the initial part of the decay, this is due to the springy nature of the soft material which causes delayed release of energy it stores.
You have thos roughness in the higher frequencies that seems typical in thin metal shallow cones. The roughness is indicated by the ridge. Otherwise, the sound would be a bit fuzzy and well balanced.
Here's something if interest to the discussion:
http://www.loudsoft.com/\loudsoft\my files\ALMA Paper 2003.pdf
http://www.loudsoft.com/\loudsoft\my files\ALMA Paper 2003.pdf
So even though this is a metal cone:
Your still going to loose some low level detail and you still have to deal with a massive break up issue. This doesn't look like a winner to me. I wish the lines were see through so that it would be easy to determine the amplitude of the decay rate.
Dan
I doubt it would look the same if you sent the same drivers to be Klippel scanned. It seems like there are some circular calculations that are not being done. Run the same simulation in a 3D FEA program and see what you can get.
I have no such thing, but this is getting interesting.
This site is awesome:
Loudsoft.com
Finally some meat on loudspeaker design. I need to head back to the Klippel site.
Dan
There are different ways of using a driver, so I guess the system designer will have to decide. Look at the shape of the Jordan JX125, and see how it differs.So even though this is a metal cone:
Your still going to loose some low level detail and you still have to deal with a massive break up issue. This doesn't look like a winner to me. I wish the lines were see through so that it would be easy to determine the amplitude of the decay rate.
Dan
Yes, I have one. What do you call the shape? Exponential? Its not OS so again its not something Geddes will recommend.
Zilch moved over to QSC waveguides because they measure better.
You might be able to spot store energy in the Impulse and in the FR plots themselves. I think Geddes alluded to this earlier. I just like CSDs because I can not not really see all the issues from the impulse and FR plot.
Summas do not use heavy cones relative to other 15" woofers. Its a pro audio woofer, pro audio woofers are not know to be considered "Heavy".
Also, John Janowitz (He builds the TD series drivers) has posted that its a fallacy to consider the mass of a cone as an indication of SQ. Although the TD15M is far heavier then any of the other 15" drivers but that is because of other parts and not the cone itself.
You will have to keep guessing.
I still think its a waste to worry about > 45 degree measurements ON WOOFERS today. You have changed nothing. You have only proven that since you choose very low cost drivers that you are crossing over too high so you have to worry about these off axis issues at > 45. Crossover the driver at the right point or buy better drivers.
I conceded that its pointless to debate your choice of driver actually, I still think 90 deg measurements of a woofer is overkill. Its amazing that you are still the only DIYer that I can find (trust me I looked for hours in the past couple of days) that is complaining about 90deg woofer measurements not existing and at the same time you spend no time or money to get 90 degree measurements. If Im going to complain about something Im going to spend $$$ and time to solve it myself but that is just me.
Answer this....how can many great DIY designers build great speakers without worrying about 90deg measurements. Ask Zilch why he does not look at 90degree measurements on the woofer?
Yep, its a cheap and crappy driver...you expect more for $25?
So far all your complaints about measurements comes back to your choices in drivers. Stop choosing low cost drivers and you will not have to worry so much about 90deg measurements of woofers.
Think of it this way, you think you are saving money buy only spending $25 but with all the issues, the time to address the issues then the extra $$ in XO parts, etc. You are better off doubling or tripling your $$$ spent on a better driver.
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You may want to look at the results. Speaker design requires them. If a rose were by any other name......
Dan
Fun WG CSD comparison data to look at:
Reference full range CSD data:
An externally hosted image should be here but it was not working when we last tested it.
Reference full range CSD data:
An externally hosted image should be here but it was not working when we last tested it.
163g for a pro woofer is indeed very heavy. The 2nd heaviest I know of. You definitely post a lot of misinformation with authority. I'd propose you get your facts right prior to posting. It would save everyone lot of time.
My woofers in those graphs were not low cost, but that's relative. They are $110/ea and purchased based on stated performance, not price. You may want to get your facts right prior to posting--again.🙄 My actual low cost woofers perform better far off axis however. Interesting. Higher cost does not equal better performance. It's easy to know once you start testing.
I thought you already knew no one was doing them. You could have saved yourself time it seems. I am the only one I know that has posted them. That certainly doesn't mean their useless, as evident by what I've presented, just that others haven't look at the ugly truth.
Ask Zilch if he's ever squeezed the balloon. 😉 He'll know of what you speak. And no, that has nothing to do with anything off color. It wasn't long ago that people were only looking at 1 axis. Things change when more knowledge is acquired. Such is the way of things.
Cost does not equate to quality. By your criteria and available measurements--nice looking CSD and low THD, that's an awesome driver.😉 Unless you now want to state that cost is the primary factor in SQ. By that standard, maybe a Feastrex field coil is in your future.🙂 Price was not a factor when I purchased those either. I bought speakers in the size I needed with the best performance for my then design.
Until you post something useful or factual, I'm done responding to you. I've wasted enough of my time and you've wasted enough of your own.
Dan
Awesome Soongsc! Does one window length correlate more with what you hear than another? Or do you need to look at both and maybe even more?
Dan
BTW, I've noticed that some people call you George. Is this what you prefer? Or Soongsc?
Noob Needs Help
Hey fellow Audiophiles
New to the speaker building scene, Stay in South Africa so decent speakers are expensive and hard to come by, so limited to Skytronic drivers ( bought for current 3 way project) and no name brands, please could some one advise on best (easiest )method to measure the T/S parameters, steps, hard and software etc....
Jon
Hey fellow Audiophiles
New to the speaker building scene, Stay in South Africa so decent speakers are expensive and hard to come by, so limited to Skytronic drivers ( bought for current 3 way project) and no name brands, please could some one advise on best (easiest )method to measure the T/S parameters, steps, hard and software etc....
Jon
I'd prefer focusing on the issues rather than a name in any forum.
It's really not so much as correlation with what I hear, but rather looking for areas of potential improvement. Most of the time there are no solid answers until you make an engineering judgement, and try some changes to see how it matches your judgement.
For example, if I do measurements gradually going closer and into the WG, what is it telling us?
An externally hosted image should be here but it was not working when we last tested it.
Most measurements are more useful for diagnosis rather than evaluating the final result.
I think the Modulation Transfer Function would be very helpfull for evaluation, but just can't seem to find an implementation does it adequately.
As for CSD, the full range in the previous post is what I consider a minimum performance.
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