Seems to me that if the damping material Danny recommends isn't used, the implied alternative isn't necessarily "nothing". Putting myself in Danny's shoes, I'd feel like my product wasn't given a fair chance over a technicality.
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Build of gr-research X-LS Encore
- Thread starter Rick Sykora
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- gr-research x-ls encore
Seems to me that if the damping material Danny recommends isn't used, the implied alternative isn't necessarily "nothing". Putting myself in Danny's shoes, I'd feel like my product wasn't given a fair chance over a technicality.
It is a good experiment to see what difference it makes. Too bad Amir doesn’t measure cabinet vibrations like Stereophile does, but looking at the FR & waterfall plots should show a difference.
OP
- Thread Starter
- #83
Hi Duke. Know you are new here, so welcome to ASR.
While there is really no major question over good practice, there is a matter of degree and Danny is not specific. One place he says, you might need some No Rez (main web page), another says it is highly recommended (buried at the end of the cabinet plans) and yet others (internet forums) he talks of suitable substitutes. In none of these case, does he specify how much or where to apply. He is a clearly has his fans and detractors, but I am just building his base kit and it does not have any damping included.
Lacking specific design specifications, I am testing various damping materials for effectiveness. Based on the outcome, Amir has plans to test both. Currently, he plans to start without damping as a baseline. Will see how he feels after I post my results.
Hi Duke. Know you are new here, so welcome to ASR.
While there is really no major question over good practice, there is a matter of degree and Danny is not specific. One place he says, you might need some No Rez (main web page), another says it is highly recommended (buried at the end of the cabinet plans) and yet others (internet forums) he talks of suitable substitutes. In none of these case, does he specify how much or where to apply. He is a clearly has his fans and detractors, but I am just building his base kit and it does not have any damping included.
Lacking specific design specifications, I am testing various damping materials for effectiveness. Based on the outcome, Amir has plans to test both. Currently, he plans to start without damping as a baseline. Will see how he feels after I post my results.
Thank you Rick.
Danny probably would not object to an e-mail inquiry (and were I in his shoes, I'd welcome it). My impression is that a reasonable amount of customer support is part of the package deal. Copied 'n' pasted from his Contact page:
Do you have a Question? Need more information? Please call or email us, and we will respond promptly.
GR Research Inc.
1716 Texowa Rd.
Iowa Park, Texas 76367 USA
940-592-3400
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OP
- Thread Starter
- #85
To quote one of the smarter folks I worked for in 30 years, "do you want more cheese on your pizza?"
More to come, but need to step out and deliver a computer.
maty
Major Contributor
Imagine a magazine or TV show focused on automobiles. Does anyone imagine evaluating a sports car with tires from a utility car?
The review would lose credibility as well as the medium.
The review would lose credibility as well as the medium.
OP
- Thread Starter
- #87
As mentioned earlier, was not posting further measurements until I validated the build. I have done so (with damping installed) but still need to do without it. As also posted in this thread (and elsewhere), am building to the design as supplied. Opinions about good design practice do not change what the designer supplied. Just because you happen to know what good design practice might be, does not mean that everyone buying a kit does.
Finally, Amir will decide what he wants to test and I will deliver to his spec. As this forum is Audio Science Review, I do not see any issues with us exploring an issue like damping. It is not one that has a simple one-size-fits-all answer. There are not only audibility issues, but the materials and techniques used might be affecting sound waves/pressures inside the cabinet, the way the cabinet panels vibrate, or some other aspect (like pipe resonance in a vented design).
Now let's do some science...
Finally, Amir will decide what he wants to test and I will deliver to his spec. As this forum is Audio Science Review, I do not see any issues with us exploring an issue like damping. It is not one that has a simple one-size-fits-all answer. There are not only audibility issues, but the materials and techniques used might be affecting sound waves/pressures inside the cabinet, the way the cabinet panels vibrate, or some other aspect (like pipe resonance in a vented design).
Now let's do some science...
OP
- Thread Starter
- #88
Before I share the results of my testing on damping material for the X-LS Encore, I thought it might be useful to know the following:
The felt notably blunted the ugliest of the resonances and indicates that they were likely due to standing waves formations. Still a bit of an issue at 275 Hz and a slightly greater one at 600 Hz.
Results for Test #2 (foam sheets):
Not much to say, although expected to be better than felt, looks about the same to me.
Test #3 (Acousta-stuf):
Here it seems less is more. While 2 ounces does not seem like much, it fills the back lower quarter of the cabinet. Best result so far, but maybe more is better?
Test result #4 (Foam sheet plus Acousta-Stuf)
My call is this is a bit of a draw. The 275 Hz blip seems slightly worse and the 600 Hz one is slightly better.
Hope you found this useful. My conclusion would be that Acousta-Stuf is sufficient for now. I want to see if I can isolate the remaining resonances, but probably at a point of diminishing returns. Another check I did was to see if the Bassbox sim indicates a port resonance, but the posted params for the woofer did not produce a good correlation with the real thing. So will have to measure the port directly. That is another test setup and will share later.
Finally, my brief listening tests were generally positive. My wife would probably tell you that I never met a speaker I did not like though.
- I try to be as consistent as possible and only change one thing at time as I measure.
- Unless otherwise specified, I do secure crossover boards with pan head screws and the underside of the board gets generous strips of butyl rubber. I also use butyl rubber to minimize potential component/wire vibration on the boards. So, while my intent is to keep the crossover adding any mechanical noise, the side benefit is changing the resonant modes of any panel where the crossover is mounted. For this speaker, the boards are mounted on the bottom and the lower inside of the right side panel.
- While an impedance sweep is currently my best tool for identifying resonances, it may miss some and identify others that are potentially inaudible. Even if the designer publishes his curves, it is not always clear they are fully representative of flaws in the design. In my experience, the designer's may just post sim graphs or a golden measure. A really clean graph usually indicates a really well done implementation but may just an overly ideal one too. As we have seen with some well built commercial speakers, small resonances are not all that uncommon.
- 1/4" F13 felt (originally obtained to do diffraction reduction duty on front baffles)
- 5/8" foam sheets (from Madisound and used in my Zaph kits)
- Acousta-stuf fiber fill (2 ounces from a larger Parts Express bag) applied only in lower back of cabinet
- Both 2 and 3
The felt notably blunted the ugliest of the resonances and indicates that they were likely due to standing waves formations. Still a bit of an issue at 275 Hz and a slightly greater one at 600 Hz.
Results for Test #2 (foam sheets):
Not much to say, although expected to be better than felt, looks about the same to me.
Test #3 (Acousta-stuf):
Here it seems less is more. While 2 ounces does not seem like much, it fills the back lower quarter of the cabinet. Best result so far, but maybe more is better?
Test result #4 (Foam sheet plus Acousta-Stuf)
My call is this is a bit of a draw. The 275 Hz blip seems slightly worse and the 600 Hz one is slightly better.
Hope you found this useful. My conclusion would be that Acousta-Stuf is sufficient for now. I want to see if I can isolate the remaining resonances, but probably at a point of diminishing returns. Another check I did was to see if the Bassbox sim indicates a port resonance, but the posted params for the woofer did not produce a good correlation with the real thing. So will have to measure the port directly. That is another test setup and will share later.
Finally, my brief listening tests were generally positive. My wife would probably tell you that I never met a speaker I did not like though.
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Vini darko
Major Contributor
Thankyou for the in depth test. I'm surprised it made so much difference. Figured it was mostly reflections but still was expecting to be way wrong somehow.
ta240
Major Contributor
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Would a first time builder know to contact him and ask based on a single line saying "You might also want to add a sheet of No Rez. See No Rez. " on the item page?
If Dodge sold the Hellcat with Prius tires and simply mentioned in a single line on their site that "you might want better tires on your Hellcat" then I would expect the automotive testers to try it as sold.
I think if anything can be taken from this debate it is that the people and companies selling DIY kits of any type need to step back and realize that they should not assume or expect a certain level of expertise or knowledge on the part of the person building the item. This is an entry level DIY 'kit' and as such should have all the needed info spelled out for the shopper. The DIY crowed continuously say they want to get more people into the hobby but every time they have a chance to make it easier for new builders they don't bother.
Gr-research spent 4 times the space selling his tube connectors on that page as he did mentioning damping material. That would indicate that damping material is far less important than tube connectors.... or possibly just far less profitable.
I built the Zaph SR71 speaker and on his site he goes into incredible detail on the build, variations that can be done down to exactly where and how much damping to put in. If he can do that on site where he provides the information for free then it is time for the sites that are selling to step up.
We don't really know. Depends on how much knowledge they already have, how meticulous they are, and what their priorities are. Some DIYers want to get everything right and trust the designer; some want to inject their own ideas into the mix as much as possible (for better or for worse) so that it's "their baby" too; and some just want a decent cost-effective solution.
On whether or not to include damping I can see arguments both ways, and I have an opinion. Rick and Amir have now heard it, so I will trust their judgment.
And based on Rick's post number 83 above, it sounds like I have nothing to complain about.
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I like that you are testing without and then With various Materials.
I looked up a popular DIY type speaker on a site that’s name could be used in knee surgery.
The Phil BMR has an option for some material but it’s not included in the “standard” kit.
It may mention to add in the instructions but that information isn’t available in the ordering info from what I could tell.
That might be a good speaker to look at since there are DIY and smaller companies that sell the same completed speaker.
Damping material probably needs a separate thread since this is about a certain speaker build and kind of a tangent to the thread here.
Thanks again for the build and insight into it.
I looked up a popular DIY type speaker on a site that’s name could be used in knee surgery.
The Phil BMR has an option for some material but it’s not included in the “standard” kit.
It may mention to add in the instructions but that information isn’t available in the ordering info from what I could tell.
That might be a good speaker to look at since there are DIY and smaller companies that sell the same completed speaker.
Damping material probably needs a separate thread since this is about a certain speaker build and kind of a tangent to the thread here.
Thanks again for the build and insight into it.
OP
- Thread Starter
- #93
Pleased you found some value in my tests.
The BMR designer is Dennis Murphy and he is a frequent ASR contributor. I approached him about testing it and he felt it would be overkill. If you are interested, there is an active thread here:
https://www.audiosciencereview.com/...udio-bmr-speaker-discussion.13667/post-413989
I have another thread on a Speaker cabinet design and will take your suggestion and either cross post my tests there or on a new thread. The tests were done on the Encores but would apply to many other speakers too. I ran out of time, but would like to show what happens when you overuse damping material too. Maybe when I build the other Encore.
maty
Major Contributor
Danny Richie continually insists in his forums on the need for damping, recommending his product No-Rez. That its website is uncared for is evident, and that it has other priorities as well.
maty
Major Contributor
Your cabinets have very few internal reinforcements so despite the thickness of the MDF they require additional damping, especially when we are talking about a 6.5" woofer.
OP
- Thread Starter
- #97
Maybe a little out of place, but thanks for sharing.
Do not know all the history, but is yours an XL-S Encore or the original AV123 XL-S?
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Mine is Curve Acoustics X-LS Encore, it's a prebuilt pair for South East Asian market and I assume is/was an authorized distributor for GR Research.
maty
Major Contributor
A little more off-topic, how do they sound compared to your new 3-ways with ribbon Wharfedale Evo4.2?
https://www.wharfedale.co.uk/evo4-2/
https://www.wharfedale.co.uk/evo4-2/
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If the EVOs are 10, the X-LS maybe around 6 or 6.5. But it's all subjective. It just happens that I like the EVOs much, much more than the X-LS.
