I have been making measurements on some drivers I have, and decided to build another center channel speaker. The woofer is a RS270p-4. It's discontinued, and I only have one, so, it's a good match for a center.
The mid will likely be a Peerless 5.25" HDS GFC. I might change my mind, and use something else that I currently own.
I have several good tweeters to pick from. I plan to use a Peerless H26TG45-06.
I made measurements recently, and simed a x-over. Nothing final, but it looks like 16 parts will be enough to get a good response.
The box will be sealed. I've been using the woofer in a 1 cu-ft box. I will check, but I think I can reduce that a little. My plan is for a tapered baffle that also has a slight slope.
The mid will likely be a Peerless 5.25" HDS GFC. I might change my mind, and use something else that I currently own.
I have several good tweeters to pick from. I plan to use a Peerless H26TG45-06.
I made measurements recently, and simed a x-over. Nothing final, but it looks like 16 parts will be enough to get a good response.
The box will be sealed. I've been using the woofer in a 1 cu-ft box. I will check, but I think I can reduce that a little. My plan is for a tapered baffle that also has a slight slope.
A quick sim shows that .5 cu-ft will be large enough for the woofer. I Want a small box, but I will need a fair amount of space for the x-over, so I may end up at 1.25 cu-ft, including the mid chamber.
I may detour a little before I start building a complicated box shape. What I will probably do first is add a baffle to an existing box, and make a x-over. If that goes well, I will continue. If it goes really well, I may stick with a more traditional boxy shape. What I need to confirm, is that the x-over is not going to get messy. I have measurements already, but the baffle will change the required x-over somewhat.
I want to keep the box short enough that it does not block the projected image. On the other hand, I'm willing to raise it on a stand five or six inches for some programming, if it makes a difference in sound quality. This is the primary reason that I want to taper the box. If I'm casting a shadow on the bottom of the screen, I would rather it be 6" wide, than 12".
Here's a sim that I made from my measurements. I stacked a small 2-way speaker onto a second box containing the woofer. Actually, the tweeter was on a 3rd box.
I want to keep the box short enough that it does not block the projected image. On the other hand, I'm willing to raise it on a stand five or six inches for some programming, if it makes a difference in sound quality. This is the primary reason that I want to taper the box. If I'm casting a shadow on the bottom of the screen, I would rather it be 6" wide, than 12".
Here's a sim that I made from my measurements. I stacked a small 2-way speaker onto a second box containing the woofer. Actually, the tweeter was on a 3rd box.
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I checked my other center, and have decided that this speaker should be 30" tall. The width at the woofer needs to be 12" minimum 14" would be better.
I'd sharpen the woofer to mid filters. That will reduce distortion on the mid and improve headroom. The Peerless 5" are great, but they don't handle a lot of power at all, so a sharper cut off will improve things.
I've crossed the 5.25" to a sub at 80hz without any problem. It can handle a 300hz 2nd order easily for my use.
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I got a little done on the box construction. The odd angles are a challenge. It was cold this morning so I worked on a x-over instead, using two stacked boxes. The tweeter is not the one I plan to use, but I think matching the other will not be a problem. Here are some measurements. Off axis about 20 degrees which is where my seats are. These are gated measurements, taken indoors. The speaker was only on a 24" stand so, it is what it is. Needs to be higher. It will change some with the new baffle, and other tweeter anyway. I just wanted to get a jump on the x-over, and see if there were any surprises. My sim for the mid was no good. I used a zma for a different driver. I resorted to trial and error for this. If I have enough energy left, I'll move it into place, and give it a listen.
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Well, it sounds different than my other speakers. Not sure if the difference is an improvement. It's a voicing issue, I suppose. This sounded more laid back in comparison. Voices seemed softer, and smoother, but some vocals seemed to lack a little bite that perhaps I just prefer. I'm on the fence as to whether or not to continue with the design.
The x-over was all 3rd order electrical, and there were three padding resistors, so the x-over part count was 15. That's not terrible, but it would require that I buy one driver, and a few coils to replace my on hand parts. I keep needing 2.5mH coils, and coming up short. I would likely add another notch on the mid at 4.5k too, so, that's three more parts. Might get crowded in the box fitting a large x-over.
I may change the mid to a 4" Peerless HDS driver I have, and raise the x-over points. The 4" is very smooth up to 4k, and beyond. I suspect the x-over might be a little easier, maybe with second order filters, and without needing the 2.5mH in the mid high-pass.
The x-over was all 3rd order electrical, and there were three padding resistors, so the x-over part count was 15. That's not terrible, but it would require that I buy one driver, and a few coils to replace my on hand parts. I keep needing 2.5mH coils, and coming up short. I would likely add another notch on the mid at 4.5k too, so, that's three more parts. Might get crowded in the box fitting a large x-over.
I may change the mid to a 4" Peerless HDS driver I have, and raise the x-over points. The 4" is very smooth up to 4k, and beyond. I suspect the x-over might be a little easier, maybe with second order filters, and without needing the 2.5mH in the mid high-pass.
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