Thanks to the people in the NET I've learned about this potential problem.
However it seems that commercial systems completely ignore that "feature": if one looks at the frequency response of these systems one can see a FR that is (at its best) flat.
On the other side I had the chance of experimenting with a B&W 704. They are declared as flat. When positioned near the walls the basses had the tendency of mix up with the mediums. I've got a decent results only with the speakers in the middle of the room (so, no ... WAF at all).
So, it seems to me that the reflections from the back greatly reduce the problem. People says only by 3dB, it could be more.
What is your thought and experience ?
Thanks
However it seems that commercial systems completely ignore that "feature": if one looks at the frequency response of these systems one can see a FR that is (at its best) flat.
On the other side I had the chance of experimenting with a B&W 704. They are declared as flat. When positioned near the walls the basses had the tendency of mix up with the mediums. I've got a decent results only with the speakers in the middle of the room (so, no ... WAF at all).
So, it seems to me that the reflections from the back greatly reduce the problem. People says only by 3dB, it could be more.
What is your thought and experience ?
Thanks
I think you've confused baffle step with room nodes. The baffle step takes place where the baffle is one wavelength wide; above the step frequency the radiation is unidirectional, below it radiation is omnidirectional. When the radiation shifts from unidirectional to omnidirectional there is an on-axis SPL drop of 6dB.
If the baffle is 30cm wide the baffle step takes place at about 1130 Hz; a 15cm wide baffle has the step at 2260 Hz and so forth. For that reason the baffle step is primarily a midrange concern. Your problem is more likely to be related to room response frequency nodes.
If the baffle is 30cm wide the baffle step takes place at about 1130 Hz; a 15cm wide baffle has the step at 2260 Hz and so forth. For that reason the baffle step is primarily a midrange concern. Your problem is more likely to be related to room response frequency nodes.
Until no w ...
Until now I have received two contrasting answers:
1. BSC is ignored by commercial designers because there are other nightmares caused by in room positioning that tend to obfuscate the (eventual) BSC solution
2. When measuring FR, commercial designers already take into account BSC, so the FR diagrams one can find in magazines are made flat (+3-6dB in the 2pi region) in some way (active vs. passive compensation)
Until now I have received two contrasting answers:
1. BSC is ignored by commercial designers because there are other nightmares caused by in room positioning that tend to obfuscate the (eventual) BSC solution
2. When measuring FR, commercial designers already take into account BSC, so the FR diagrams one can find in magazines are made flat (+3-6dB in the 2pi region) in some way (active vs. passive compensation)
I could agree but ...
I could agree but ... how can one distinguish ?
I've never, never heard about it in the (italian) magazines.
I read Audio Review and Costruire Alta Fedeltà (CHF).
Let me give some examples:
I could agree but ... how can one distinguish ?
I've never, never heard about it in the (italian) magazines.
I read Audio Review and Costruire Alta Fedeltà (CHF).
Let me give some examples:
- Wilson Audio Sophia, 18550€
- Focal JM Lab Diva Utopia, 10550€
- Nagra HP, 24000€
- Mission Pilastro, 37000€
[/list=1]
All the FR are flat, measured by the magazine and they never mention BSC.
Please, don't assume that I'm saying that BSC is a no-problem, that all of you are crazy or deaf, I'm only trying to understand the problem and then take my decisions (and spend some amount/a lot of money).
Thanks
They don't mention BSC because its accounted for.
go to www.seas.no and look at the graphs of the drivers
measured in boxes, not in flat baffles, the 6dB baffle step
should be obvious.
Note a bass/ mid driver measuring 91dB on a large baffle
= one that will measure flat in a box at 85dB with BSC.
sreten.
go to www.seas.no and look at the graphs of the drivers
measured in boxes, not in flat baffles, the 6dB baffle step
should be obvious.
Note a bass/ mid driver measuring 91dB on a large baffle
= one that will measure flat in a box at 85dB with BSC.
sreten.
I know of two very high priced speakers that do not have any baffle step at all. The Krell LAT-2 and the Wilson Audio Cub. I have measured them too. (I own LEAP 5 and LMS 4 from LinearX...) There is an online review of the Krell somewhere that clearly shows the drop in output below 800 Hz or so. Both speakers sound incredibly bright and fatiguing, especially after a lengthy listening session. (5 minutes )
A usual giveaway to no BSC is speakers that have very high efficiency ratings. (The CUB is rated at 93 dB I believe...) Taking 3 to 6 dB of efficiency away from a speaker for something that many consumers are completely unaware of (and usually don't understand) doesn't look good on paper, and usually isn't in their best interest since most speaker companies are out to sell speakers. Sad but true. On the salesfloor, it is often akin to selling televisions. The brightest TV always looks the best to untrained eyes. Any speakers being A/B'ed with a pair of Klipsch speakers will typically "lose" if the person giving the comparison is not adjusting the gain.
)A usual giveaway to no BSC is speakers that have very high efficiency ratings. (The CUB is rated at 93 dB I believe...) Taking 3 to 6 dB of efficiency away from a speaker for something that many consumers are completely unaware of (and usually don't understand) doesn't look good on paper, and usually isn't in their best interest since most speaker companies are out to sell speakers. Sad but true. On the salesfloor, it is often akin to selling televisions. The brightest TV always looks the best to untrained eyes. Any speakers being A/B'ed with a pair of Klipsch speakers will typically "lose" if the person giving the comparison is not adjusting the gain.
Thank you
Thank you Sreten. I noticed that some drivers seemed to roll off more prematurely than others. I always wondered why and I never noticed the <The loudspeaker is mounted in a closed box ...> statement (the font is really too little !).
Thank you lowHz. The first thing I shall do will be to write to Audio Review (and others) and ask for the measurement criteria. This way of declaring the loudspeaker characteristics seems (commercially) a dirty trick.
Thank you Sreten. I noticed that some drivers seemed to roll off more prematurely than others. I always wondered why and I never noticed the <The loudspeaker is mounted in a closed box ...> statement (the font is really too little !).
Thank you lowHz. The first thing I shall do will be to write to Audio Review (and others) and ask for the measurement criteria. This way of declaring the loudspeaker characteristics seems (commercially) a dirty trick.
Re: Thank you
IMO you won't get very far questioning the measurement regime
of a magazine, as long as nearfield measurements are not used
above 200Hz, any baffle step will clearly show up in measurements
and in the room averaged response.
The most famous speaker without BSC is the wilson WATT, as its
designed as a nearfield monitor, BSC is provided by the Puppy.
Its also far more disturbing to me the number of amateur designs
that simply ignore BSC as an inconvenience and don't mention it.
The Ariel / ME2 for one being a classic case in point.
sreten.
teodorom said:
IMO you won't get very far questioning the measurement regime
of a magazine, as long as nearfield measurements are not used
above 200Hz, any baffle step will clearly show up in measurements
and in the room averaged response.
The most famous speaker without BSC is the wilson WATT, as its
designed as a nearfield monitor, BSC is provided by the Puppy.
Its also far more disturbing to me the number of amateur designs
that simply ignore BSC as an inconvenience and don't mention it.
The Ariel / ME2 for one being a classic case in point.
sreten.Quoting the Wilson site, the Cub "is designed to excel in bookshelf or other enclosed installations." In other words it's meant to mount on or near a boundary and baffle step compensation would not be appropriate. Speakers positioned away from walls need BSC and those positioned near them do not. All decent speakers include BSC when it's appropriate. They don't advertise it because it's such an obvious thing in crossover design that it's taken for granted. If the speaker measures pretty flat in the 200-1000 region, with the speaker mounted where the manufacturer says to, they've designed in the right amount of BSC for its intended use.
Designed ? it could be ...
The more I learn about speakers design the more I'm disappointed by the design of the commercial systems.
Usually Audio Review (Italian) publishes the cross-over schema, and one sees everything: usually BSC not taken into account, impendance rise of the woofer not compensated, or compensated before the low pass filter, impendace peak of the tweeter not compensated, or compensated before the high pass filter, "simple" filters that do nothing, and so on ...
The more I learn about speakers design the more I'm disappointed by the design of the commercial systems.
Usually Audio Review (Italian) publishes the cross-over schema, and one sees everything: usually BSC not taken into account, impendance rise of the woofer not compensated, or compensated before the low pass filter, impendace peak of the tweeter not compensated, or compensated before the high pass filter, "simple" filters that do nothing, and so on ...
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