What is the difference between BSC (Baffle Step Compensation) and attenuation of a mid/tweeter? I understand the baffle width/wavelength reflection theory but I don't get how a resistor/inductor network can change things beyond timing..
Help this old brain figure this out..
Thanks in Advance!
Help this old brain figure this out..
Thanks in Advance!
It doesn't. There is a reason this is called compensation and not correction. The baffle step is a three dimensional effect and a crossover is one dimensional.
sreten..
Thank you! The physical (Mechanical) part of it helps me to understand it more. The action-reaction approach works better in my mind..
AllenB..
Now I need to play around with it and actually "hear" the difference to understand this part. I've built the perfect candidate to mess with.. Thank You..
I assume this goes inline before the crossover network?
Thanks again..
Thank you! The physical (Mechanical) part of it helps me to understand it more. The action-reaction approach works better in my mind..
AllenB..
Now I need to play around with it and actually "hear" the difference to understand this part. I've built the perfect candidate to mess with.. Thank You..
I assume this goes inline before the crossover network?
Thanks again..
Sorry for the confusion.. Maybe I didn't use the correct words? (I'm a noob.. Gimmie a break..)
Does the BSC circuit get installed before the crossover network or directly to the lower range driver after the crossover?
For all that I've read, it is simply installed before the crossover at the feed point of the speaker. Is this correct? (I can design one, I'm sure..)
Quote.. ME..
"I've built the perfect candidate to mess with.."
This means that I have a speaker unit that I can experiment with. I am experiencing an issue with bass response and I believe the issue may be baffle step syndrome..
I wanna hear this 3D thing. Sounds like fun!
Does the BSC circuit get installed before the crossover network or directly to the lower range driver after the crossover?
For all that I've read, it is simply installed before the crossover at the feed point of the speaker. Is this correct? (I can design one, I'm sure..)
Quote.. ME..
"I've built the perfect candidate to mess with.."
This means that I have a speaker unit that I can experiment with. I am experiencing an issue with bass response and I believe the issue may be baffle step syndrome..
I wanna hear this 3D thing. Sounds like fun!
Thanks Again, sreten..
What changes? The SPL of the highs? If I'm using a simple 2 way 1st order cross over, (Inductor on the low range and cap/resistor on the highs) does the properties of the cross over inductor need to be lowered because of the added inductance of the BSC? I imagine the cross over point of the tweet is pretty much fixed by the chosen capacitor?
My "Victim" is a home brew unit so changes can be made on the fly. I'm still experimenting and learning..
Just trying to get a grip on this..
Thanks in Advance!
What changes? The SPL of the highs? If I'm using a simple 2 way 1st order cross over, (Inductor on the low range and cap/resistor on the highs) does the properties of the cross over inductor need to be lowered because of the added inductance of the BSC? I imagine the cross over point of the tweet is pretty much fixed by the chosen capacitor?
My "Victim" is a home brew unit so changes can be made on the fly. I'm still experimenting and learning..
Just trying to get a grip on this..
Thanks in Advance!
Think of it this way, you could cross the speakers without regard for the step, and then apply EQ to the system that gives a tilt to compensate for it. This way all frequencies above the step will be approximately 6dB lower than the low frequencies.
In broad generic terms, this could mean using an inductive reactance of, say 8 ohms in series with the woofer to apply the 6dB reduction of the highs. You might put an 8 ohm resistor across this inductor to set the maximum reduction of the highs. You would then treat the driver as 16 ohms for the purpose of crossing it in the normal sense, and reduce the tweeter by 6dB as well.
Due to the interaction of all the above it might be necessary to adjust these values, and may be possible to combine some of the components.
As it turns out, with a large enough baffle the step will happen where the room is in control and a 3D fix may be less difficult.
In broad generic terms, this could mean using an inductive reactance of, say 8 ohms in series with the woofer to apply the 6dB reduction of the highs. You might put an 8 ohm resistor across this inductor to set the maximum reduction of the highs. You would then treat the driver as 16 ohms for the purpose of crossing it in the normal sense, and reduce the tweeter by 6dB as well.
Due to the interaction of all the above it might be necessary to adjust these values, and may be possible to combine some of the components.
In order to fix a 3D effect you need to use 3D methods.I wanna hear this 3D thing. Sounds like fun!
As it turns out, with a large enough baffle the step will happen where the room is in control and a 3D fix may be less difficult.
To expand on this, say you apply compensation in the common way. After a while you decide that your bass needs some adjustment and you identify a room mode that is causing some of the problem.
You deal with the mode and find you are able to adjust the amount of compensation you use, and this averages the remaining bass issues out a little to bring the whole response a little closer to correct.
What I observed..
I have a 6.5" 4 ohm driver and a 2.5" 8 ohm paper tweet. I have .33mh on the 6.5" and 9.4mf on the tweet. That should cross the tweet at ~2-2.5k and the 6.5" at ~2-2.5k.. (Unknown SPL for either.. Playing midnight baseball here..)
I have 7 ohms on the tweet to pad it down to a reasonable level. Sounded somewhat balanced but the bass was a little thin..
Built a quickie BSC with some parts I had laying around. (1mh. and 4.4 Ohms) Sure knocked the highs down.. LOL.. I need to remove some resistance to the tweet to bring it up a little.. (Lost some brightness!) Sounds more controlled, though..
Gotta love playing around..
Don't have much of a baffle. I'm playing with a box very similar to this.. (Only sealed and the tweets are now paper)
I have a 6.5" 4 ohm driver and a 2.5" 8 ohm paper tweet. I have .33mh on the 6.5" and 9.4mf on the tweet. That should cross the tweet at ~2-2.5k and the 6.5" at ~2-2.5k.. (Unknown SPL for either.. Playing midnight baseball here..)
I have 7 ohms on the tweet to pad it down to a reasonable level. Sounded somewhat balanced but the bass was a little thin..
Built a quickie BSC with some parts I had laying around. (1mh. and 4.4 Ohms) Sure knocked the highs down.. LOL.. I need to remove some resistance to the tweet to bring it up a little.. (Lost some brightness!) Sounds more controlled, though..
Gotta love playing around..
Don't have much of a baffle. I'm playing with a box very similar to this.. (Only sealed and the tweets are now paper)
Last edited:
Yes, tweaking has its advantages. I can guess that you are playing enough in the dark that the crossover is giving at least the error that the baffle might be.. ie at this level tweaking won't likely give you a clear picture of what's happening.
I assume you see the strange logic behind reducing the upper midrange and wanting to increase the treble, which suggests there was too little of the latter and it was hidden behind too much of the former.
Eg, with 7 ohms in series with the tweeter, it might be cutting closer to 1K, lower even if the resonance is around there. Using a shunt element is not essential but may provide a little more predictability..ie either an L-pad or a second order high pass filter.
I assume you see the strange logic behind reducing the upper midrange and wanting to increase the treble, which suggests there was too little of the latter and it was hidden behind too much of the former.
Eg, with 7 ohms in series with the tweeter, it might be cutting closer to 1K, lower even if the resonance is around there. Using a shunt element is not essential but may provide a little more predictability..ie either an L-pad or a second order high pass filter.
I have the resistance on the tweet before the capacitor, between the source and the tweet circuit. The capacitor is directly connected to the tweet. Am I safe to assume that I'm not changing the cross over point but changing level going to the tweet?
I have the .33mh inductor connected in the same fashion. (Directly inline to the 6.5" and the source) Just a simple 1st. order crossover with attenuation to the tweet..
I definitely heard the difference by installing my quickie BSC. It just opened another page for me to experiment with..
Thank You!
I have the .33mh inductor connected in the same fashion. (Directly inline to the 6.5" and the source) Just a simple 1st. order crossover with attenuation to the tweet..
I definitely heard the difference by installing my quickie BSC. It just opened another page for me to experiment with..
Thank You!
No OffGrid, this is a common mistake. Having one current path, you need to look at a series circuit like a train on a track. No matter in which order the carriages are they are just as heavy to pull (same impedance).
WOW.. Just when I thought I was getting somewhere..
Thanks, AllenB for your patience. I believe I understand the concept/theory better. I'm starting to understand why the properties of the driver(s) are so important..
I'll bet you guys that have a grip on this stuff would like to reach out, grab a handful of shirt, and slap us noobs silly sometimes..
Anyhow.. Back at BSC world..
I connected my quickie compensation unit to a set of 4 ohm 2-way coaxial speakers that was designed by a much more educated person than myself. Definitely changed the character of them. Bass response increased, mids tamed down but kept the upper treble. (Actually sucked down the mids a little too much) I assume a little too much inductor and resistance? I'll play with it..
Thanks, AllenB for your patience. I believe I understand the concept/theory better. I'm starting to understand why the properties of the driver(s) are so important..
I'll bet you guys that have a grip on this stuff would like to reach out, grab a handful of shirt, and slap us noobs silly sometimes..
Anyhow.. Back at BSC world..
I connected my quickie compensation unit to a set of 4 ohm 2-way coaxial speakers that was designed by a much more educated person than myself. Definitely changed the character of them. Bass response increased, mids tamed down but kept the upper treble. (Actually sucked down the mids a little too much) I assume a little too much inductor and resistance? I'll play with it..
Haha. No, it's when people convince themselves that cables make a difference in speakers that I let them work it out for themselves.
One thing many conventional speakers have in common is that the baffle is slightly wider than the woofer. As a result the baffle compensation often happens a little below the crossover. It is not unusual to simply increase the roll-off to the woofer and attenuate the tweeter.
One thing many conventional speakers have in common is that the baffle is slightly wider than the woofer. As a result the baffle compensation often happens a little below the crossover. It is not unusual to simply increase the roll-off to the woofer and attenuate the tweeter.
I have 2-8" 4 ohm coaxial drivers in a box (~.3/half) stuffed with some fiberglass. They don't sound too bad but lack base directly in front of the unit. I tried attenuation to the tweet but by the time things leveled out somewhat, it was too much..
I added my quickie BSC unit to the mix. Increased the choke to 2mH. Made a big difference! I have a .33mH. to the woofer of the coax and I need to go a little lower (.20mH?) to let a little more mids through..
Actually, this circuit (BSC) has given me the results that I've been looking for. I've tried all types of standard 1st. order configurations but never found the sound I wanted. This has opened a new page for me..
I plan on building a "Test Fixture" with a variable resistor (Stereo L-Pad) and 5 different inductor levels to be inserted into the source line to any speaker(s) I want to mess with. (1, 1.5, 2, 2.5, and 3mH. per channel) Simply flip switches to introduce inductance and adjust the resistance on the fly. (For 4 or 8 ohm) Get the specifics from the test unit, construct the circuit and wala.. Sound practical?
I added my quickie BSC unit to the mix. Increased the choke to 2mH. Made a big difference! I have a .33mH. to the woofer of the coax and I need to go a little lower (.20mH?) to let a little more mids through..
Actually, this circuit (BSC) has given me the results that I've been looking for. I've tried all types of standard 1st. order configurations but never found the sound I wanted. This has opened a new page for me..
I plan on building a "Test Fixture" with a variable resistor (Stereo L-Pad) and 5 different inductor levels to be inserted into the source line to any speaker(s) I want to mess with. (1, 1.5, 2, 2.5, and 3mH. per channel) Simply flip switches to introduce inductance and adjust the resistance on the fly. (For 4 or 8 ohm) Get the specifics from the test unit, construct the circuit and wala.. Sound practical?
Last edited:
If it is working for you then yes, this road forward will help you optimise the correction up to the limits of what it is capable of.
This looks to me like a classic statement of the effect of taking a portion of the spectrum that has response errors, and trying to balance it against the rest of the spectrum, despite that the peaks and dips still exist. Or alternately (but the same thing in a manner of speaking), trying to compensate a step where the correction uses the wrong turnover frequency.
@ Lojzek..
The only test equipment I have is a multi meter and my ears. I purchase the cheapest drivers that I can find that I feel is worth messing with. Most don't have any specs to be found..
My situation doesn't allow me to have much test equipment. My work shop is my living room and a set of saw horses to cut things outdoors with battery powered tools. (And a VERY understanding wife..)
I'm a weekend warrior and fit this hobby into my life, being I work a full time job and commuting ~80 miles a day..
This is a hobby, not an obsession. (Although my wife may have a different opinion..) I have my ears and I know what I want to hear. I'm slowly figuring out what does what to adjust sound. Might be the cave man way but I'm having fun doing it. I'm just your typical hillbilly audiophile wannabe..
I may frustrate the **** out of you guys but I don't have much to work with. My only option is to gather information, apply it to the best of my ability and listen. (Warsteiner helps..) If it doesn't do what I want, I regroup and try something else or tweak the direction that I'm headed..
I'm not asking for pity, just understanding. I would love having some equipment to equate my ears to but I can't justify the cost at this point. Nor do I feel educated enough to purchase high dollar drivers..
I highly respect this place but sometimes I feel that I'm not educated enough to post anything. I apologize for not being as advanced as most but I need to learn somehow. Thanks to everyone that puts up with me..
The only test equipment I have is a multi meter and my ears. I purchase the cheapest drivers that I can find that I feel is worth messing with. Most don't have any specs to be found..
My situation doesn't allow me to have much test equipment. My work shop is my living room and a set of saw horses to cut things outdoors with battery powered tools. (And a VERY understanding wife..)
I'm a weekend warrior and fit this hobby into my life, being I work a full time job and commuting ~80 miles a day..
This is a hobby, not an obsession. (Although my wife may have a different opinion..) I have my ears and I know what I want to hear. I'm slowly figuring out what does what to adjust sound. Might be the cave man way but I'm having fun doing it. I'm just your typical hillbilly audiophile wannabe..
I may frustrate the **** out of you guys but I don't have much to work with. My only option is to gather information, apply it to the best of my ability and listen. (Warsteiner helps..) If it doesn't do what I want, I regroup and try something else or tweak the direction that I'm headed..
I'm not asking for pity, just understanding. I would love having some equipment to equate my ears to but I can't justify the cost at this point. Nor do I feel educated enough to purchase high dollar drivers..
I highly respect this place but sometimes I feel that I'm not educated enough to post anything. I apologize for not being as advanced as most but I need to learn somehow. Thanks to everyone that puts up with me..
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.