Hi,
I recently purchased a pair of the Visaton BGS40 drivers in hope of making a spinoff of the NoBox design seen at Enjoythemusic.Comsat website. When o ran this article over to a friend who has helped me with many XO designs he quickly pointed out that the claims of this design are way overinflated. Using the manufacturers data he simulated it and showed there was no way you would be able to get the bass out of this OB with these drivers like the article shows. I am wondering if anyone here has experience with this design and what it was. I am now very reluctant to spend any further effort and time on these. My plans were to use a pair of the now out of stock PE firesale noname 12" coaxial drivers with the compression tweeters inside mated to the Visatons on a similar baffle.
I would love to hear some real experience with this design.
I recently purchased a pair of the Visaton BGS40 drivers in hope of making a spinoff of the NoBox design seen at Enjoythemusic.Comsat website. When o ran this article over to a friend who has helped me with many XO designs he quickly pointed out that the claims of this design are way overinflated. Using the manufacturers data he simulated it and showed there was no way you would be able to get the bass out of this OB with these drivers like the article shows. I am wondering if anyone here has experience with this design and what it was. I am now very reluctant to spend any further effort and time on these. My plans were to use a pair of the now out of stock PE firesale noname 12" coaxial drivers with the compression tweeters inside mated to the Visatons on a similar baffle.
I would love to hear some real experience with this design.
Here's the website for the NoBox project
The VISATON NoBox BB Loudspeaker Kit Review By Dick Olsher
Jeff
The VISATON NoBox BB Loudspeaker Kit Review By Dick Olsher
Jeff
And here's the 12" I was planning on substituting for the top end...
12" Cast Frame Coaxial Pro Speaker
12" Cast Frame Coaxial Pro Speaker
I would only fear of the treble response ,not the bass ,in the No Box design.
And I would stay away from buyouts and PA drivers unless they give you what you need
precisely.
And I would stay away from buyouts and PA drivers unless they give you what you need
precisely.
I've been wondering the same for a while myself. I wanted to grab those woofers and try it out myself. It's a simple build, give it a try.
Mmmh.I didn't read the first statement of this thread ! Visaton BGS40 it's not what i would expect to perform best in a OB . Well ...+- 8mm excursion are not too bad ,but that's when the cone is nearly leaving to ...🙂
Maybe Jmiller did refer to this idea when thinking of doubling the cones and adding a tweeter :
http://www.diyaudio.com/forums/multi-way/165169-big-ob-fun-come-hear.html
Maybe Jmiller did refer to this idea when thinking of doubling the cones and adding a tweeter :
http://www.diyaudio.com/forums/multi-way/165169-big-ob-fun-come-hear.html
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From the pics, it looks similar in concept to MJKs passive baffle and it suffers no lack of bottom... if the Visaton is low Q some Q may be called for.
dave
dave
I would say build it. Low Q doesn't mean lack of bass... a 15" driver is barely moving and it takes some amount of EQ before you can run it out.
It will probably need some EQ on the bottom end. The beauty of OB is its simplicity. For minimum effort, you can get pretty decent sound. This design can almost certainly be made to work.
It will probably need some EQ on the bottom end. The beauty of OB is its simplicity. For minimum effort, you can get pretty decent sound. This design can almost certainly be made to work.
Nice friend you've got. 🙄
Could you tell us what he simulated and how it could be nearer to reality than the measurements of Dirk Olsher? How did he include the side wings into his simulation? How did he account for the floor boost? Any simulations short of Boxsim or MJKs worksheets probably won't do justice to the NoBox.
Rudolf
It never fails to amaze me how someone can simulate something and declare whether or not same works in reality.
Really?! You've got to be kidding! How do you think we flew to the moon and back? Do you also think CAD is snake oil? Have you flown in a commercial jet liner lately? Exactly how amazed are you?
Anyways, I have included below some of my friends argument about the claims of the article in question, below is what he recently wrote to me in an email. I am having trouble adding his graph right now.
His argument:
"That driver won't produce 40Hz dipole at 105db if you dropped it from 30,000ft from the cabin of a jet liner. Not to mention it is excursion limited to about 50W of power. Below is it's measured response on an infinite baffle notice by 50Hz it's 1W sensitivity is not 98db but more in the range of 85db. When you couple that with the fact that on a 20" wide baffle the baffle step loss will be about 6db and on a dipole the dipole loss will be about 6db the real sensitivity down around 50Hz is going to be in the range 73db of course you might get some room gain of say 5-6db. In order to do this you would need a parametric equalizer and several more of the woofers to keep up with your single 12" midrange driver.
The graph above does not lie, While this driver does have 98db of sensitivity from 300Hz up it has greatly diminished sensitivity below that. By the time that driver gets to 100Hz it has lost 8db of sensitivity, by the time it gets to 40Hz it has lost about 17db of it's sensitivity. This is on an infinite baffle. Of course the first inclination would be to equalize the input signal that is fine but it runs out of xmax at just 40W. Which means if I give it 40W at 40Hz, I need to only give it .75W at 100Hz to get the same output and this is before the baffle step losses."
Since I can't add his graph I will describe it.....it is a standard SPL to freq plot, area if interest shows the curve at around 100db at 500hz gradually dropping tp about 85db at 50hz.
Please tell me where his reasoning is flawed.
My friend is a well respected member of this forum who I have retained his identity at the moment...he is known by many here and is quite experienced at this stuff. In fact he has helped quite a few people here with XO designs and such. Anyway, his point to me was the Mr. Dirk Olsher measurements should be viewed with skepticism. Just because someone says it's true doesn't make it so. Do you personally know Dirk Olsher? Are you sure his measurements posted in the article haven't been exaggerated for reasons of profit or fame?
As many of you know in the world of HIFI audio there is quite a lot of Bull Sh$t claims out there for reasons of profit or fame.
But really, what I am interested in is someone who has built this thing themselves. How did they experience this design.....
I use simulations almost everyday. I never said they do not have a place. Simulations will certainly give you quick answers in their perfect world. My world however is not perfect and I have more than once had a simulated circuit fall down in my imperfect world.
I am actually in an airport departure lounge awaiting a commercial flight. I also used to fly both fixed and rotary wing aircraft. I always preferred flying the craft myself than relying on aircraft subsystems. Not saying e.g autopilot is not nice but I rather do it myself.
Why not build it, put it in a room and measure it?
Did your friends simulation take into account the inductors in the woofer circuit, that they should me iron core and their effect on driver Qt?
As to man on the moon, well, there are some who would dispute that😀
I am actually in an airport departure lounge awaiting a commercial flight. I also used to fly both fixed and rotary wing aircraft. I always preferred flying the craft myself than relying on aircraft subsystems. Not saying e.g autopilot is not nice but I rather do it myself.
Why not build it, put it in a room and measure it?
Did your friends simulation take into account the inductors in the woofer circuit, that they should me iron core and their effect on driver Qt?
As to man on the moon, well, there are some who would dispute that😀
The mail of your friend puts some things into perspective. 🙂
I don't know Mr. Olsher, but I don't see anything wrong in his measurements either.
Note that Dick Olshers first measurement is in the nearfield - as stated in the text below the graph. His second measurement graph is not very far from the free field response as given by the manufacturer for the Nobox kit - with different power levels of course.
I have added a diagram where you can see the absolute limits of the Nobox. They are reached at 105 dB @ 1m at 60 Hz and at 500 Hz.
Rudolf
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105 db is near concert level. I don't think you would want to be in the same room as a speaker that is producing 105 db @40 Hz.
I use simulations everyday, but they can often be wrong. At the end of the day, the simulation program is written by a human being and you can rest assured that assumptions/simplifications have been made. The extent to which it correlates with the real world, let alone what you percieve, is highly debatable. The best thing to do is build it, listen to it, measure it yourself, and above all, enjoy it.
Unless you are trying to fill a room the size of a small theatre, this woofer should suffice. You will definitely need some EQ.
I use simulations everyday, but they can often be wrong. At the end of the day, the simulation program is written by a human being and you can rest assured that assumptions/simplifications have been made. The extent to which it correlates with the real world, let alone what you percieve, is highly debatable. The best thing to do is build it, listen to it, measure it yourself, and above all, enjoy it.
Unless you are trying to fill a room the size of a small theatre, this woofer should suffice. You will definitely need some EQ.
yeah but if it were 105 db at 40 hz it WOULD be stupid loud at 1K.
I agree with this guy 100%; this is clearly the wrong speaker for a
headbanger.
get some cerwin vega or klipsch or something like that . your ears and
your money are wasted on a nice speaker like this.
I agree with this guy 100%; this is clearly the wrong speaker for a
headbanger.
get some cerwin vega or klipsch or something like that . your ears and
your money are wasted on a nice speaker like this.
If by 'subjectively' you are referring to the Fletcher-Munson curves, then they vary by level. 105db@40Hz is perceived differently than 80db@40Hz. Similarly, the relative perceived loudness between 1kHz and 40 Hz also varies with level.
I'm not doubting jmillerdoc's friend's calculations. Even then, there should be enough bass given some EQ.
Whether Dick Olsher is right or wrong is beside the point IMO. This design will work in a moderate sized room and normal listening levels is all I'm saying.
I'm not doubting jmillerdoc's friend's calculations. Even then, there should be enough bass given some EQ.
Whether Dick Olsher is right or wrong is beside the point IMO. This design will work in a moderate sized room and normal listening levels is all I'm saying.
At the end of the day my hopes were to find someone who had actually built these and get their perspective. I own the BGS40's and several sheets of wood. It's not much of a project to knock together in an afternoon. I just didn't want to waste time and resources if this article was hugely over exaggerated. I know I can make these drivers perform much better in a BR and that's where they ultimately may end up. For now I guess I will build it (different top end) and get back here with some real world measurements. I have a Beringher 2way stereo electronic XO I will use here with a Parasound HCA800 hooked to the Visatons and one of my tube amps to the top end. Will cross around 250hz and fiddle from there.
Anybody have any thoughts of trying a Fostex 166e in place of the Visaton B200? I happen to have a pair of these on the shelf, thought they might work well here.
Suggestions?
Suggestions?
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