Hi Everyone,
I am building a pair of sealed enclosures for a pair of fr125s - basically the 7L reflex box, 3/4" baltic birch, no port. This is my first loudspeaker project (aside from a car subwoofer.) So I've got a couple of questions:
1. Stuffing: I am most concerned with the back wave reflecting off the back of the cabinet and returning delayed through the cone. I can't cut angles, (a router is the only tool I have out here) - what do I do to prevent this? Current plan is to use pillow stuffing, fairly tightly compressed along the walls, with looser stuffing below the brace in the bottom of the cabinet, and some empty space immediately behind the driver. Will this be sufficient? Should I line the walls with carpet pad instead?
2. Filters: there are some filters floating around for the 7L reflex box: a broad 'notch' around 1500hz, and a narrower notch around 7000hz. Will these work with the sealed enclosure as well?
Appreciate any advice!
I am building a pair of sealed enclosures for a pair of fr125s - basically the 7L reflex box, 3/4" baltic birch, no port. This is my first loudspeaker project (aside from a car subwoofer.) So I've got a couple of questions:
1. Stuffing: I am most concerned with the back wave reflecting off the back of the cabinet and returning delayed through the cone. I can't cut angles, (a router is the only tool I have out here) - what do I do to prevent this? Current plan is to use pillow stuffing, fairly tightly compressed along the walls, with looser stuffing below the brace in the bottom of the cabinet, and some empty space immediately behind the driver. Will this be sufficient? Should I line the walls with carpet pad instead?
2. Filters: there are some filters floating around for the 7L reflex box: a broad 'notch' around 1500hz, and a narrower notch around 7000hz. Will these work with the sealed enclosure as well?
Appreciate any advice!
Hi,
try this filter for a closed box (with 6dB high-pass). It is in German and "a / b / c / d" are the filter values. The designer is "cyburgs" from Austria - some of you might know him. The plan is free for private use, commercial use only on request!
Regards
Thorsten
try this filter for a closed box (with 6dB high-pass). It is in German and "a / b / c / d" are the filter values. The designer is "cyburgs" from Austria - some of you might know him. The plan is free for private use, commercial use only on request!
Regards
Thorsten
Attachments
Thank you validator.
I finished the enclosures this past weekend (except for the roundover on the baffles and trimming the baffle and back flush with the rest of the box. They sound pretty good right now without any filters, but I'm wondering if they could be improved.
I notice that Cyburgs design has a 7" baffle - mine is based on the CSS design, only they are left sealed right now. Similar displacement, but 6.5" baffle width. This would push the baffle step up to a higher frequency, right? Will the filters still work?
Will the notch filter in cyburgs design work for a narrower baffle? Does the notch require the 470uF cap as well, or is that just to extend f3?
Attached some pictures; one of the speakers, one of my workshop. My wife did permit me to glue up the boxes in the apartment, but any of the messy stuff had to be done outside. Thankfully, temperatures have been a little warmer lately.
Stuffed the bottom half of the enclosure and back wall with a poly-fil product that looks like insulation (its sold in sheets) - this made life pretty easy.
Any tips for finishing baltic birch? I like the look of them now, but I think they might look nice in a dark walnut or something similar...
I finished the enclosures this past weekend (except for the roundover on the baffles and trimming the baffle and back flush with the rest of the box. They sound pretty good right now without any filters, but I'm wondering if they could be improved.
I notice that Cyburgs design has a 7" baffle - mine is based on the CSS design, only they are left sealed right now. Similar displacement, but 6.5" baffle width. This would push the baffle step up to a higher frequency, right? Will the filters still work?
Will the notch filter in cyburgs design work for a narrower baffle? Does the notch require the 470uF cap as well, or is that just to extend f3?
Attached some pictures; one of the speakers, one of my workshop. My wife did permit me to glue up the boxes in the apartment, but any of the messy stuff had to be done outside. Thankfully, temperatures have been a little warmer lately.
Stuffed the bottom half of the enclosure and back wall with a poly-fil product that looks like insulation (its sold in sheets) - this made life pretty easy.
Any tips for finishing baltic birch? I like the look of them now, but I think they might look nice in a dark walnut or something similar...
Attachments
Hi Gio,
The speakers sound pleasant, but I think they can be improved. I have a pair of commercial speakers that I compared them to - my goal was (and still is) to match or better their performance.
I think there may be an opportunity to improve the sound with filters, adding a port to the box, or adding a tweeter. My next project is going to be a measurement microphone, so I can identify areas that can be improved.
Is your offer for a mini meet still open? I'll send you an e-mail.
The speakers sound pleasant, but I think they can be improved. I have a pair of commercial speakers that I compared them to - my goal was (and still is) to match or better their performance.
I think there may be an opportunity to improve the sound with filters, adding a port to the box, or adding a tweeter. My next project is going to be a measurement microphone, so I can identify areas that can be improved.
Is your offer for a mini meet still open? I'll send you an e-mail.
I have FR125S' in a 7L box. I found that sealed they sounded constipated. I believe most of the recommendations are for a 10-14L sealed box. I've never heard that size, but I wasn't happy with the 7L sealed.
I don't know about that big filter on the FR125S. Pretty much ruins the directness of a full-ranger? I haven't heard mine with a filter. I just use them a foot from the wall, so I don't need BSC. If you're going to add a tweeter, again you'll spoil the full-range quality IMO.
If you don't want to try a larger box, I suggest you try a stuffed port. That's what I'm using now, and I love the sound, as long as you don't get carried away with the volume.
I don't know about that big filter on the FR125S. Pretty much ruins the directness of a full-ranger? I haven't heard mine with a filter. I just use them a foot from the wall, so I don't need BSC. If you're going to add a tweeter, again you'll spoil the full-range quality IMO.
If you don't want to try a larger box, I suggest you try a stuffed port. That's what I'm using now, and I love the sound, as long as you don't get carried away with the volume.
Thanks for the advice. I have some ports and foam plugs that I could install; might be worth a try.
Did some more listening tonight. Certain music sounds great on these speakers - anything simple and well recorded. Once there are more than three instruments, echo, or complex sounds, everything seems to blur together. But simple music sounds pretty good.
My commercial speakers seem to be a lot more forgiving of lower quality recordings.
Did some more listening tonight. Certain music sounds great on these speakers - anything simple and well recorded. Once there are more than three instruments, echo, or complex sounds, everything seems to blur together. But simple music sounds pretty good.
My commercial speakers seem to be a lot more forgiving of lower quality recordings.
Port Tube
I'm going to install the port tube that came with the kit this weekend. It's the CSS flared port - looks something like this:
I'm a little confused by the flanges at the back of the port. The flanges are 3/4" long - same as the wall material that I'm using. Should I cut the hole to the OD of the flange, or to the OD of the pipe, and then cut slots into the wood for the flanges to seat in?
I'm going to install the port tube that came with the kit this weekend. It's the CSS flared port - looks something like this:
An externally hosted image should be here but it was not working when we last tested it.
I'm a little confused by the flanges at the back of the port. The flanges are 3/4" long - same as the wall material that I'm using. Should I cut the hole to the OD of the flange, or to the OD of the pipe, and then cut slots into the wood for the flanges to seat in?
I got a chance to hear these this past weekend.
For some reason, they sounded very poor (horrible in fact) with a K-12M tube amp. I could not figure out why. Can anyone shed some light on this?
With an SS amp, we did find them bright and lacking in bass. Suspecting that a BSC may help, we pulled together a very quick 2dB BSC and found that it did make a noticable difference. However, it was apparent that it needed more BSC for my room.
The efficency of the drivers is very low and a BSC drops it even further, so you will need some power to driver these guys.
Unfortunately, I had lent away my chip amp so we never got to try this combo out. I suspect that a chip amp would mate up well with these guys.
Cheers,
Gio.
For some reason, they sounded very poor (horrible in fact) with a K-12M tube amp. I could not figure out why. Can anyone shed some light on this?
With an SS amp, we did find them bright and lacking in bass. Suspecting that a BSC may help, we pulled together a very quick 2dB BSC and found that it did make a noticable difference. However, it was apparent that it needed more BSC for my room.
The efficency of the drivers is very low and a BSC drops it even further, so you will need some power to driver these guys.
Unfortunately, I had lent away my chip amp so we never got to try this combo out. I suspect that a chip amp would mate up well with these guys.
Cheers,
Gio.
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