Yes, but not all necessarily smooth enough to avoid measurable and audible issues near the top end of their unfiltered pass band.
Take a look at the roller coaster ride on FR graphs for these above 1000Hz
A very well respected Dayton driver Aluminum cone - $149
http://www.parts-express.com/pedocs/specs/295-464-dayton-audio-rss315hf-4-specifications-46174.pdf
Peerless "state of the art" XXLS 12" Aluminum cone $263
http://www.parts-express.com/pedocs/specs/264-1114-peerless-835017-specifications-46573.pdf
Browse through the graphs for many makes / materials / price ranges for larger diameter dedicated subwoofer drivers, and you'll likely find similar issues.
I'd always use a Low Pass filter of some sort on a woofer / sub. As Pano noted in a post above, this is exactly what plate or rack mounted sub amp with filters are built for. In my own personal lexicon, it's not really a crossover unless it passes the full bandwidth to other drivers in the system.
Hi nautilusdave..............just Google: "loudspeaker crossovers". There is a lot out there.
cheers Jonathan
cheers Jonathan
I'm still here. Some of you mentioned that mounting the big 15" woofer in an open back box might actually REDUCE bass output. But others that have put these big vintage woofers in H-frames (which are open both front AND back) say they do it mostly for the increase in bass output.
This is part of the discouraging thing... contrary suggestions/comments. Who's right? Who's wrong? But don't want to go there. Just expressing some frustration.
If I'm' going to do the coil thing, I'll likely get that 9mH coil from parts express. I may just go ahead and build a mock-up H-frame, install the big woofer, connect it up and listen... kind of a "proof of concept" experiment.
This is part of the discouraging thing... contrary suggestions/comments. Who's right? Who's wrong? But don't want to go there. Just expressing some frustration.
If I'm' going to do the coil thing, I'll likely get that 9mH coil from parts express. I may just go ahead and build a mock-up H-frame, install the big woofer, connect it up and listen... kind of a "proof of concept" experiment.
I know how you feel. Go for it. The coil would be the simplest to do. Trust your ears and have fun. 🙂
Laws of physics apply. The woofer may sound louder across most of its frequency range, but will suffer cancellations at its low end. So you need to prevent sound waves from the front meeting their doppelgangers from the back. If you use an H frame, you would need to use a lot of sound absorbant stuffing in the back. That might work...
Sent from my phone with Tapatalk. Please excuse any typpos.
Funny thing is, both are correct! 😀 But it's relative. Relative to what you compare it to.
If you compare an open back box to a closed back box, you will have less bass in the open back. If you compare and H-Frame to a flat baffle of the same size, the H-Frame will have more bass. All relative.
Here's the basic idea:
Put a woofer on a baffle and play it. The bass from the front will meet the bass from the back. Since they are of opposite phase (think about how the front and back of the woofer move) they will cancel out. The wider the baffle, the lower the cancellation frequency will be, because of the wavelengths. Longer is lower, or lower is longer.
Now put a woofer in a box. The back waves and the front waves can't meet, you've blocked almost all the back waves from getting out. No bass cancellation. Box has more bass, because of no cancellation.
What about an H-Frame? You could see it as a folded open baffle. It might be 18" across, but the H wings mean the front and back sounds have to travel farther to meet and cancel. Farther means longer wavelength, means lower frequency.
There are a lot more complications to it than that, but that's the very basic idea.
The problem with putting the sub in a sealed box is the back pressure inside the box tends to reduce the excursion of the cone causing less bass.
This is why the bigger the box for bass the better.
It's complex - but I wanted to get across the basics.
Hence why one may prefer to use a ported box or folded horn. All different ways to increase the effective distance between the front and back of the speaker cone.
Sent from my phone with Tapatalk. Please excuse any typpos.
You might check to see if you can buy one in the right range.
https://www.parts-express.com/800-hz-low-pass-4-ohm-crossover--266-448
I still really doubt that a xover is actually needed here.
Sent from my phone with Tapatalk. Please excuse any typpos.
Sent from my phone with Tapatalk. Please excuse any typpos.
OK... I have built an H-frame cabinet that has a 15" vintage Heppner 8 ohm speaker mounted in it. I have a pair of full range 8 ohm drivers (8 inch) serving as my L & R front pair.
Now, I'm a bit befuddled on how to wire this thing in as sort of a passive subwoofer. My receiver is rated at 8 ohms. So how do I wire in these 3 into my 2-channel receiver? Any wiring is going to have to be at the "speaker level,"
I had it wired a certain way but the receiver got hot, so I probably had it wired as a 4-ohm parallel load to my receiver.
Is there a way to wire in this passive 15" woofer and not stress my receiver?
Now, I'm a bit befuddled on how to wire this thing in as sort of a passive subwoofer. My receiver is rated at 8 ohms. So how do I wire in these 3 into my 2-channel receiver? Any wiring is going to have to be at the "speaker level,"
I had it wired a certain way but the receiver got hot, so I probably had it wired as a 4-ohm parallel load to my receiver.
Is there a way to wire in this passive 15" woofer and not stress my receiver?
Last edited:
You'll only be able to connect it to one channel as you have it at present. Because your amp is rate at 8 ohms it will have to be in series with one of the 8 inch. The problem is this will half the output because the signal is divided between the two speakers and what is more you will be only getting the bass from the one channel. I'm afraid this arrangement will not give you any kind of meaningful comparison to your Polk sub.
Yeah.. I thought that might be the case.
Is there something else I can do to try and integrate this into my system? I could build a second one, but really don't want/need it. What else does it need to act as a "passive" sub for both channels?
To use the one sub for both channels the signals have to be mixed. This is what happens in your polk sub. The two channels are mixed then go through a crossover, then amplifier to the speaker. There is no way to mix the two channels 'passively'. You can either have two passive subs or do it the way the polk does. That's why I suggested you actually use the polks speaker connections but it would mean removing the speaker but it would give you an excellent comparison
I have some 4 ohm resistors that I could put in-line somewhere to make it so that the receiver "sees" 8 ohms or more and won't be stressed.
If I connected both of the receiver speaker outputs (R and L) to the sub, then from the sub connected the 8" full rangers, where would I put the 4 ohm resistors to ease the stress on the receiver's amp?
If I connected both of the receiver speaker outputs (R and L) to the sub, then from the sub connected the 8" full rangers, where would I put the 4 ohm resistors to ease the stress on the receiver's amp?
- Status
- Not open for further replies.