Surround speakers

[jordan456789]

You could use one driver in the design with the passive crossover from the kit. Few people really need the second driver. But it would be out of budget in the end.

I like the RB Kit center idea. All he needs is to buy one kit and I'll mail him the extra driver I have. I know MTMs aren't ideal, but for the price he could have a very nice speaker.

I like the idea of getting the RB Kit and adding the extra driver. One question i have is i assume the crossover is built for the drivers it comes with. If i add the extra one how would i work the crossover? Thanks alot for your help in breaking me into the DIY concept

 

[Guiria]

I like the idea of getting the RB Kit and adding the extra driver. One question i have is i assume the crossover is built for the drivers it comes with. If i add the extra one how would i work the crossover? Thanks alot for your help in breaking me into the DIY concept

You are right. The crossover is not designed for 2 drivers + tweeter, also the crossover is probably designed around a given baffle width and if you are putting in two drivers and making a very wide baffle (center channel placed horizontal) then that will affect the crossover as well. The overall system impedence will be much lower as well which is another factor that will affect the performance of your standard crossover.

Crossovers are typically designed around a specific number of drivers, baffle size, etc...any changes to that and you run the risk of adversely affecting the speaker performance.

I would recommend just building the kit as is without modifcation to achieve the optimal results for which the kit was designed.

You may be able to find help on these audio forums about modifying the RB crossover to accomodate another driver. I'd help you if I knew what I was doing

 

[lsiberian]

You are right. The crossover is not designed for 2 drivers + tweeter, also the crossover is probably designed around a given baffle width and if you are putting in two drivers and making a very wide baffle (center channel placed horizontal) then that will affect the crossover as well. The overall system impedence will be much lower as well which is another factor that will affect the performance of your standard crossover.

Crossovers are typically designed around a specific number of drivers, baffle size, etc...any changes to that and you run the risk of adversely affecting the speaker performance.

I would recommend just building the kit as is without modifcation to achieve the optimal results for which the kit was designed.

You may be able to find help on these audio forums about modifying the RB crossover to accomodate another driver. I'd help you if I knew what I was doing

I don't believe the speakers have a Baffle Step in them. At least not the one I got. BSC is unecessary if you put the speaker against the wall. Doing it with a passive crossover I believe to be foolish because every environment and setup would benefit from a different compensator. The best way to correct the sound is by the use of a parametric crossover. The cheapest commercially available product that does this well is the Behringer Feedback destroyer. However it is limited to 2 channels. So you would need about 2 of them to cover the front sound stage. The process can be time consuming though and many prefer an automated eq system. Which is less customizable but far less work as well. AS should easily compensate for any Baffle step issues.

Baffle step is the ability of sound waves to form off the front of the speaker essentially. Longer wave length LFE's take longer to form essentially. The idea is that you can compensate for this in your crossover. But by placing the speaker on a wall. You essentially gain the entire wall for waves to form. I prefer this method. 1. It gives a wider soundstage for the LFE portion of a sound track. 2. It leaves out a circuit design complication and simplifies the crossover design.

However there are always detractors and those who argue for it. Plus not every can put their speakers up against the wall. My setup is unique and prefers this type of placement.

My logic may be flawed so take that under advisement. My study of sound and acoustics is still in an elementary state. Nonetheless I felt it appropriate to share what I gleaned for the education of others. If what I've gleaned from other sources is inaccurate feel free to add and correct where necessary. We have a singular goal here. The best sound possible for the money and time involved.

 

[Guiria]

I don't believe the speakers have a Baffle Step in them. At least not the one I got.

I did not review the crossover of the RB kit so I'm sure you are right about that one

BSC is unecessary if you put the speaker against the wall.

I agree here as well, a BSC circuit and wall mounting may lead to boominess in the midbass frequency region.

Doing it with a passive crossover I believe to be foolish because every environment and setup would benefit from a different compensator.

If you include atleast some baffle step compensation in a crossover you atleast have it there should you not put your speaker against or into a wall. Many will argue that your speakers will sound the best away from back and side walls, having BSC is crucial if this is the case. I've owned speakers with and without a BSC circuit in the xover design and I much prefer the sound with the BSC.

The best way to correct the sound is by the use of a parametric crossover. The cheapest commercially available product that does this well is the Behringer Feedback destroyer. However it is limited to 2 channels. So you would need about 2 of them to cover the front sound stage. The process can be time consuming though and many prefer an automated eq system. Which is less customizable but far less work as well. AS should easily compensate for any Baffle step issues.

I'm not sure how you would use a BFD to correct baffle step since you are adjusting a very wide frequency range one way (ie from 500 hz up). If you used external amplification and a DCX2496 then it would be easily done.

Baffle step is the ability of sound waves to form off the front of the speaker essentially. Longer wave length LFE's take longer to form essentially. The idea is that you can compensate for this in your crossover. But by placing the speaker on a wall. You essentially gain the entire wall for waves to form. I prefer this method. 1. It gives a wider soundstage for the LFE portion of a sound track. 2. It leaves out a circuit design complication and simplifies the crossover design.

If you are designing a speaker to be placed on a wall or in an entertainment center, etc then leaving out the BSC is probably a good idea. If you plan on placing the speaker away from the wall I would recommend a BSC circuit. Whether it be 2 or 6 db's that is up to you, your speaker's sensitivity will change when a BSC circuit is added. Check this link out on designing your own BSC circuit http://diyaudioprojects.com/Technical/Baffle-Step-Correction-Circuit-Calculator/

Also this is an effective article to show what the BSC is actually doing and what BSC is http://www.quarter-wave.com/General/BSC_Sizing.pdf

The beauty of DIY is you can chose one way and if down the road you do not like it or change speaker location, etc you can always make adjustments to optimize your setup.

We have a singular goal here. The best sound possible for the money and time involved.

I couldn't agree more. I hope the OP is soaking all this in like a sponge

Another note about adding a second driver. I would guess the crossover has some form of attenuation circuit to match the tweeter's SPL to the woofer SPL. If so, and you add another woofer your system may not sound balanced because you have increased your woofer's nominal SPL output by adding a second driver, not to mention reducing the system impedence considerably. The center may sound boomy and dull all at once :|

Just my 2 cents...

 

[lsiberian]

I did not review the crossover of the RB kit so I'm sure you are right about that one



I agree here as well, a BSC circuit and wall mounting may lead to boominess in the midbass frequency region.



If you include atleast some baffle step compensation in a crossover you atleast have it there should you not put your speaker against or into a wall. Many will argue that your speakers will sound the best away from back and side walls, having BSC is crucial if this is the case. I've owned speakers with and without a BSC circuit in the xover design and I much prefer the sound with the BSC.



I'm not sure how you would use a BFD to correct baffle step since you are adjusting a very wide frequency range one way (ie from 500 hz up). If you used external amplification and a DCX2496 then it would be easily done.



If you are designing a speaker to be placed on a wall or in an entertainment center, etc then leaving out the BSC is probably a good idea. If you plan on placing the speaker away from the wall I would recommend a BSC circuit. Whether it be 2 or 6 db's that is up to you, your speaker's sensitivity will change when a BSC circuit is added. Check this link out on designing your own BSC circuit http://diyaudioprojects.com/Technical/Baffle-Step-Correction-Circuit-Calculator/

Also this is an effective article to show what the BSC is actually doing and what BSC is http://www.quarter-wave.com/General/BSC_Sizing.pdf

The beauty of DIY is you can chose one way and if down the road you do not like it or change speaker location, etc you can always make adjustments to optimize your setup.



I couldn't agree more. I hope the OP is soaking all this in like a sponge

Another note about adding a second driver. I would guess the crossover has some form of attenuation circuit to match the tweeter's SPL to the woofer SPL. If so, and you add another woofer your system may not sound balanced because you have increased your woofer's nominal SPL output by adding a second driver, not to mention reducing the system impedence considerably. The center may sound boomy and dull all at once :|

Just my 2 cents...

It does have attenuation. So we'll see how I end up handling that. I'm not going to building them for some time. And by that time I'm hopeful of having a DCX2496. My next step is the MBM(in progress) then the TC sounds sub so it's pretty far down the line for me. I also have no plans to make an MTM. I much prefer to make mine a TMM. I want to keep that Tweeter in line with my ears and I can't do that with an MTM/PJ setup.

As far as BSC. I've found movies to be very enjoyable with wall placement, while music tends to be better with compensation, but that's my observation in my own room. And since this is a center channel you probably won't use it for music much.

 

[jordan456789]

I don't believe the speakers have a Baffle Step in them. At least not the one I got. BSC is unecessary if you put the speaker against the wall. Doing it with a passive crossover I believe to be foolish because every environment and setup would benefit from a different compensator. The best way to correct the sound is by the use of a parametric crossover. The cheapest commercially available product that does this well is the Behringer Feedback destroyer. However it is limited to 2 channels. So you would need about 2 of them to cover the front sound stage. The process can be time consuming though and many prefer an automated eq system. Which is less customizable but far less work as well. AS should easily compensate for any Baffle step issues.

Baffle step is the ability of sound waves to form off the front of the speaker essentially. Longer wave length LFE's take longer to form essentially. The idea is that you can compensate for this in your crossover. But by placing the speaker on a wall. You essentially gain the entire wall for waves to form. I prefer this method. 1. It gives a wider soundstage for the LFE portion of a sound track. 2. It leaves out a circuit design complication and simplifies the crossover design.

However there are always detractors and those who argue for it. Plus not every can put their speakers up against the wall. My setup is unique and prefers this type of placement.

My logic may be flawed so take that under advisement. My study of sound and acoustics is still in an elementary state. Nonetheless I felt it appropriate to share what I gleaned for the education of others. If what I've gleaned from other sources is inaccurate feel free to add and correct where necessary. We have a singular goal here. The best sound possible for the money and time involved.

I am reading the posts and trying to understand everything but you say it would be foolish to use a passive crossover. Would i have to get a separate amp just to run the center channel or would you just recomend getting a EQ? My TV and stand are up against the wall and my center speaker is in the stand so it is very close to the wall so i wouldn't need baffle.

 

[lsiberian]

I am reading the posts and trying to understand everything but you say it would be foolish to use a passive crossover. Would i have to get a separate amp just to run the center channel or would you just recomend getting a EQ? My TV and stand are up against the wall and my center speaker is in the stand so it is very close to the wall so i wouldn't need baffle.

I think you will still want to build a crossover for the speaker.

I suggest the recession Destroyer instead.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-700

It's already planned out as an MTM.