Hi. Got hold of an old (but hardly used) pd.182. Thought I would build a (sub)woofer for my old man. The x-max limits ultra low end, but what would you do? Any suggestions (exept selling and buying something else) will be appreciated. Music is the main thing here. Not HT.
Attachments
Last edited:
Greets!
Well, selling it would be pretty far down by list of choices since I prefer ~critically damped alignments using high Vas, low Fs, Qts drivers obviously designed for pounding high SQ mid bass in a relatively small cab or big horn, so to the first approximation a Vb = Vas, Fb = Fs yields a T/S max flat alignment if some form of EQ is used to raise the effective Qts to ~0.403, so a bit less EQ/net Vb if a higher tuning is required and a bit more if tuning lower. TL or MLTL alignments preferred.
Since this eats up LF dynamic headroom, getting as much room gain as practical is desirable, so hopefully there’s a usable corner available. That, or place it near the listening position [LP] in a coffee table or similar.
If corner loaded, then the cab can be smaller and/or tuned lower to get the desired ~flat in-room response. EQ’d sealed may be enough considering you reside where homes are much better constructed than where I live.
If space, weight, build cost isn’t an issue, then some form of pipe horn [tapered TL such as the ‘BIB’] would be my choice, but then I like to listen to low B pipe organ symphonies, so need at least a 16 Hz tuning; otherwise, a ~27.5 – 32 Hz tuning to get the lowest note on a Concert Grand piano suffices unless he listens to some of the newer electronic stuff that I’m told needs a somewhat lower tuning. The main thing is that if vented, one ideally wants a tuning no higher than ~ 1.22x the lowest note to be reproduced and preferably at or below this frequency.
GM
Well, selling it would be pretty far down by list of choices since I prefer ~critically damped alignments using high Vas, low Fs, Qts drivers obviously designed for pounding high SQ mid bass in a relatively small cab or big horn, so to the first approximation a Vb = Vas, Fb = Fs yields a T/S max flat alignment if some form of EQ is used to raise the effective Qts to ~0.403, so a bit less EQ/net Vb if a higher tuning is required and a bit more if tuning lower. TL or MLTL alignments preferred.
Since this eats up LF dynamic headroom, getting as much room gain as practical is desirable, so hopefully there’s a usable corner available. That, or place it near the listening position [LP] in a coffee table or similar.
If corner loaded, then the cab can be smaller and/or tuned lower to get the desired ~flat in-room response. EQ’d sealed may be enough considering you reside where homes are much better constructed than where I live.
If space, weight, build cost isn’t an issue, then some form of pipe horn [tapered TL such as the ‘BIB’] would be my choice, but then I like to listen to low B pipe organ symphonies, so need at least a 16 Hz tuning; otherwise, a ~27.5 – 32 Hz tuning to get the lowest note on a Concert Grand piano suffices unless he listens to some of the newer electronic stuff that I’m told needs a somewhat lower tuning. The main thing is that if vented, one ideally wants a tuning no higher than ~ 1.22x the lowest note to be reproduced and preferably at or below this frequency.
GM
Thanks for putting in your time and effort gentlemen. 
I am not that good at reading these technical posts, but a 154liter tapped horn with a f3 tuned to about 30hz is what I get out of it. This is absolutely doable. Is there a cut-sheet option in Hornresp bjorno..? A "hey presto" button of sorts..?
The (sub)woofer will be placed in a corner. (unlike Baby ) In addition this is a loft/attic with slanted roof. The speakers under one slant and listening position under the other. (dont know how to explain this better in english...) Distance between is about 3 meters. The woofer would "see" about 30-35m2. The slanted roof means that the m3 will be smaller than a normal 30-35m2 room.
EQ will be done by minidsp, and a PA-amp will provide power. (make and model yet to be desided)
Sealed would be great GM, but then I presume that 30-40hz would be out of the question..? Even with EQ..?
I am not that good at reading these technical posts, but a 154liter tapped horn with a f3 tuned to about 30hz is what I get out of it. This is absolutely doable. Is there a cut-sheet option in Hornresp bjorno..? A "hey presto" button of sorts..?
The (sub)woofer will be placed in a corner. (unlike Baby
) In addition this is a loft/attic with slanted roof. The speakers under one slant and listening position under the other. (dont know how to explain this better in english...) Distance between is about 3 meters. The woofer would "see" about 30-35m2. The slanted roof means that the m3 will be smaller than a normal 30-35m2 room. EQ will be done by minidsp, and a PA-amp will provide power. (make and model yet to be desided)
Sealed would be great GM, but then I presume that 30-40hz would be out of the question..? Even with EQ..?
Yes, you can EQ it to this low, just that how much peak SPL is available will depend on how much room gain you have. Around here +6 dB is a lot, but up to +9 dB is possible in well constructed rooms, though I imagine the TTQWT will play at least as loud at lower power until of course audible distortion forces you to back off the volume control a bit.
Anyway, looks like ~104 dB/m in half space is the Xmax limit, so figure at least 110 dB/m in a corner and maybe a bit more.
GM
Anyway, looks like ~104 dB/m in half space is the Xmax limit, so figure at least 110 dB/m in a corner and maybe a bit more.
GM
Hi
Yes it is. No cut-sheet but you can print out a dimensioning record from HR:
Here is just a pixel doodled suggestion:
b
Attachments
Thanks again bjorno.
This is a tossup between sealed and TH. Sealed is tempting because of size and ease of build, but I have built several speakers and subs before so TH is not out of the question. Any suggestions on size for the sealed option?
Sidenote... I have two pd.186 waiting for a BR-enclosure (I already have two in my HT). I must say that it is tempting to use one sealed for my living room...
This is a tossup between sealed and TH. Sealed is tempting because of size and ease of build, but I have built several speakers and subs before so TH is not out of the question. Any suggestions on size for the sealed option?
Sidenote... I have two pd.186 waiting for a BR-enclosure (I already have two in my HT). I must say that it is tempting to use one sealed for my living room...
Apparently not. I had in mind a somewhat larger cab up to at least 100 L net and as much as the TH’s ~154 L net to allow more in room tuning flexibility at a potentially higher SQ, i.e. trading cab efficiency for greater LF BW and ~’critically’ damped roll-off [0.5 Qtc], if there’s enough room gain available to justify it.
GM
I had in mind a somewhat larger cab up to at least 100 L net and as much as the TH’s ~154 L net to allow more in room tuning flexibility at a potentially higher SQ, i.e. trading cab efficiency for greater LF BW and ~’critically’ damped roll-off [0.5 Qtc], if there’s enough room gain available to justify it.GM
I get around 4 dB in a corner, but have a very open/lossy constructed home. Where you live though, the weather dictates much better construction, sealing, so at least 6 dB seems a given. Above this point though, increasing gain gets tough to come by. A concrete basement buried in the ground on three sides only gave a little more than 7 dB, so to get the theoretical 9 dB probably requires a NASA mission control bunker.
GM
GM
Ok. Had a couple of mdf-boxes (about 100liters) sitting around doing nothing. Thought I might as well try sealed. Threw on a new baffle and cut a new hole. Tried both in my home theater and livingroom. Must say I am pleasently surprised. Still got som fine tuning to do, but nothing wrong with the amount of bass (for music at least).
Should I run these with a highpass filter? I have one sitting at 30hz now. 48db/oct. Should I run them flat or is a low shelf from 100hz and down ok/necessary? To put it another way. How should I EQ this sealed sub? I dont have to much excurtion to play with.
Should I run these with a highpass filter? I have one sitting at 30hz now. 48db/oct. Should I run them flat or is a low shelf from 100hz and down ok/necessary? To put it another way. How should I EQ this sealed sub? I dont have to much excurtion to play with.
PRECISION DEVICES PD 182
If you are happy with your 100L then make a reflex.
Ports: (for VB = 92.9 L, FB = 34.5 Hz)
2 ports diam (int.) 9.4 cm and L = 28.8 cm
You have a better low range output. If having an accurate measure for the ports (internal dimension like 4") state so we can calibrate it's length, with the volume of the enclosure (try to measure the internal L x W x D.)
Another interesting enclosure if you have one driver is joining the 2 boxes together for an extreme sub (new ports calculations) whatever that means.
If you are happy with your 100L then make a reflex.
Ports: (for VB = 92.9 L, FB = 34.5 Hz)
2 ports diam (int.) 9.4 cm and L = 28.8 cm
You have a better low range output. If having an accurate measure for the ports (internal dimension like 4") state so we can calibrate it's length, with the volume of the enclosure (try to measure the internal L x W x D.)
Another interesting enclosure if you have one driver is joining the 2 boxes together for an extreme sub (new ports calculations) whatever that means.
Last edited:
Not really answering the question here... Why would I go reflex when I am happy with the output? This is only for music.
I allready have a 160liter reflex and a TQWT simmed, but want a smaller box. The test box was 100 liters. The final box will be about 80. I dont need an extreme sub. Just one that will work for my old father when listening to music. Pd.182 sealed was/is more than enough..
Actually, I am so satisfied that I will go sealed with one or two pd.186 in my own living room. With almost twise the x-max it will be fine for music, even at my listening levels.
I allready have a 160liter reflex and a TQWT simmed, but want a smaller box. The test box was 100 liters. The final box will be about 80. I dont need an extreme sub. Just one that will work for my old father when listening to music. Pd.182 sealed was/is more than enough.
. Actually, I am so satisfied that I will go sealed with one or two pd.186 in my own living room. With almost twise the x-max it will be fine for music, even at my listening levels.
That's your money and time. You should know what is better...
Simulations for both PD 182 vs. PD 186.
F3 difference is considerable as a pointer to the rest, range/extension. But for Jazz and same type of music quality is more important and the sealed speakers are good performers. In the case of the PD 182 I would get more ~5dB in the region that's needed ie., around 30Hz and in the LF extension.
Attachments
Money and time have little to do with it. I have all the drivers, and the pd.182 cost less than $50.
In real life the pd.182 in sealed performs really well. Much better than expected. As stated before this is for my father for listening to blues at 80-95db max. I have testet with many different types of music and dont find it lacking in performance for any type.
Now, how about advise regarding post #14?
I have all the drivers, and the pd.182 cost less than $50. In real life the pd.182 in sealed performs really well. Much better than expected. As stated before this is for my father for listening to blues at 80-95db max. I have testet with many different types of music and dont find it lacking in performance for any type.
Now, how about advise regarding post #14?
PD 182
To me is perfect, it also must be for your father (it looks great on paper plus you must get a good room-gain from the slanted roof or something). Also as a sealed you have plenty (?) excursion to play width. I mean you have constant 6mm (Xmax) at a max. amp power of 110W (RMS). It doesn't get higher like a BR does for a high pass at 30Hz, but others can give a more informed opinion about that and EQ (that you say your sound is excellent already so don't touch it). Power: what amp are you/will be using?! you say you are not using more than 1W (80-95dB) when the speaker is 96.2 dB/W/m or 97.5 dB/2.83V/m @ 1.00 m (each speaker). Maybe not exactly just making some sense about what you said. From distance 1M to distance 3 meters SPL will decay 6dB's if I'm right.
1x speaker/sub - away from the walls - you need 7 Watts for 95 dB SPL at listening position (3 meters)
1x speaker/sub - In a corner (within 18 to 24 inches) - you need 2 Watts for 95.7 dB SPL at listening position (3 meters)
I didn't say it isn't.
To me is perfect, it also must be for your father (it looks great on paper plus you must get a good room-gain from the slanted roof or something). Also as a sealed you have plenty (?) excursion to play width. I mean you have constant 6mm (Xmax) at a max. amp power of 110W (RMS). It doesn't get higher like a BR does for a high pass at 30Hz, but others can give a more informed opinion about that and EQ (that you say your sound is excellent already so don't touch it). Power: what amp are you/will be using?! you say you are not using more than 1W (80-95dB) when the speaker is 96.2 dB/W/m or 97.5 dB/2.83V/m @ 1.00 m (each speaker). Maybe not exactly just making some sense about what you said. From distance 1M to distance 3 meters SPL will decay 6dB's if I'm right.
1x speaker/sub - away from the walls - you need 7 Watts for 95 dB SPL at listening position (3 meters)
1x speaker/sub - In a corner (within 18 to 24 inches) - you need 2 Watts for 95.7 dB SPL at listening position (3 meters)
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.