Bass reinforcement is often a matter of speaker placement and seating position within the listening room. After much trial and error, I have found that using the guidelines in http://www.immediasound.com/Speaker%20set-up%202009.pdf results in good bass reinforcement even from small[ish] speakers.
My typical listening position is to have the speakers close to the room's midline a little out from the walls and adjust my position between the back wall and the 1/4 length listening for best balance. My room is much too long to position the speakers on "the long wall."
Also, relative to the FAST discussion, I'm a firm believer in taking the large cone movements resulting from bass from the fr drivers and putting them on a dedicated lf driver. I guess the design difference is that I MUCH prefer 1st order crossovers even though they do 'leak' more bass into the fr driver.
My typical listening position is to have the speakers close to the room's midline a little out from the walls and adjust my position between the back wall and the 1/4 length listening for best balance. My room is much too long to position the speakers on "the long wall."
Also, relative to the FAST discussion, I'm a firm believer in taking the large cone movements resulting from bass from the fr drivers and putting them on a dedicated lf driver. I guess the design difference is that I MUCH prefer 1st order crossovers even though they do 'leak' more bass into the fr driver.
I would suggest a separate D-class amplification channel for each driver, paired with DSP filtering. I am using the Hypex AS2.100 modules in this project.
Hi Justin, Guys,
Apologies, that I haven't replied to your most recent posts, I'm in the assembly factory working on production for Japan, UK and USA.
Its 4.20am in the morning as I type so its very hectic for me until the end of the week. I'm also preparing for guesting at 2 Tokyo audio shows on 9th and 10th of October.
I'll do my best to answer your points soonest.
Thanks
Mark.
Apologies, that I haven't replied to your most recent posts, I'm in the assembly factory working on production for Japan, UK and USA.
Its 4.20am in the morning as I type so its very hectic for me until the end of the week. I'm also preparing for guesting at 2 Tokyo audio shows on 9th and 10th of October.
I'll do my best to answer your points soonest.
Thanks
Mark.
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Hi Justin, Swifty, Zman01, Guys,
"To woof, or not to woof, that is the question"
Apologies for the Shakespearean reference, but it does sort of illustrate the debate quite well.
Briefly, (I'm back to the production line in 40 mins), the choice of using Full-Rangers as single point source, or as part of a multi-way setup will depend on personal preference and needs.
The largest factor that's likely to determine the addition of woof (sub-woof) LF assistance is the need for more motive power. Anyone with a larger room, who has beat and rock music as part of their musical pleasure, might head towards a multi-way set up of some description.
Those (like me) who are more into classical, vocal and jazz and don't play particularly loud and likely to be devotees of single point source.
With my driver maker's hat on, designing Full-Range and Woofs presents 2 distinct challenges:
Full-Ranger's: Getting them to emit "full range" mostly centres around keeping power-train masses low. That compromises stability which in turn limits power handling. You'll note the latest Alpair 10 can go low (Fo=36Hz) but it can't sustain low output under constant heavier load conditions due mostly to its low mass cone. However, its capacity to micro-resonant in the LF condition is far superior to any woofer of comparable or larger size. Micro-resonance is key to producing fine musical detail. That leads me on to.......
Woofers: Getting woofers to emit "micro-ronannce" is a challenge. The design priority for LF emitters has to be "power handling". That means thicker cones, heavier power-trains, good for handling mechanical oscillation, not so good for the efficiency of primary emittance.
So chaps, sorry I can't type much more today, but at least this post focuses on some of the tech factors that make for interesting Diy build choices. I'll do my best to expand on these issues once I've finished building 2.5 metric tones of driver by this weekend (my back's killing me!).
Cheers
Mark.
"To woof, or not to woof, that is the question"
Apologies for the Shakespearean reference, but it does sort of illustrate the debate quite well.
Briefly, (I'm back to the production line in 40 mins), the choice of using Full-Rangers as single point source, or as part of a multi-way setup will depend on personal preference and needs.
The largest factor that's likely to determine the addition of woof (sub-woof) LF assistance is the need for more motive power. Anyone with a larger room, who has beat and rock music as part of their musical pleasure, might head towards a multi-way set up of some description.
Those (like me) who are more into classical, vocal and jazz and don't play particularly loud and likely to be devotees of single point source.
With my driver maker's hat on, designing Full-Range and Woofs presents 2 distinct challenges:
Full-Ranger's: Getting them to emit "full range" mostly centres around keeping power-train masses low. That compromises stability which in turn limits power handling. You'll note the latest Alpair 10 can go low (Fo=36Hz) but it can't sustain low output under constant heavier load conditions due mostly to its low mass cone. However, its capacity to micro-resonant in the LF condition is far superior to any woofer of comparable or larger size. Micro-resonance is key to producing fine musical detail. That leads me on to.......
Woofers: Getting woofers to emit "micro-ronannce" is a challenge. The design priority for LF emitters has to be "power handling". That means thicker cones, heavier power-trains, good for handling mechanical oscillation, not so good for the efficiency of primary emittance.
So chaps, sorry I can't type much more today, but at least this post focuses on some of the tech factors that make for interesting Diy build choices. I'll do my best to expand on these issues once I've finished building 2.5 metric tones of driver by this weekend (my back's killing me!).
Cheers
Mark.
The beauty of the helper woof XOed low is that it is pretty easy to keep the entire set of speakers within a 1/4 wavelength at the XO mainting an essentially "single point source". The trick is in getting good timbre matching and integration.
dave
Who said we do not listen to similar music. Even with this music, there is need for augmentation of the lower frequencies to get the complete experience. I agree that certain types of music present less of a challenge to the FR concept and in fact may be ideal, but even within those genres, there can be opportunity.
Based on what you have done so far and your dedication to your practice, I doubt it is not something you couldn't accomplish. I applaud your work ethic and hope it brings great success.
Hi Justin,
(referring to your comment - red text). I'm not sure where its written in stone that to get LF, every Full-Range driver on the planet must be augmented with a woof. This is not the case as higher mass power-trains have lower micro-emittance, thus compromising their musical output. Please re-read my comment regarding the primary emittance limitations on higher mass cones such as those found on many woofs.
Having made 2 woofers to date (Alp10 and Woof-6), I know the technical challenges involved. I am glad of your encouragement but your overly trans-fixed on woofs. They aint saints.
Hopefully I can make a lower mass woof but its bound to have power handling limitations if I go in this direction.
Must dash, on a coffee break while glue dries.
Thanks
Mark.
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Wasn't trying to inlcude all FR drivers in the debate. I believe the 10.2 is much closer (90%) to being a true FR unit. I LOVE it. Haven't heard the 12's. The 7.3 does some things much better than the 10.2, somethings worse. Naturally it does not have the LF extenson. No big deal, because what you get in exchange is high end extension. It is also not as sweet or soft sounding as the 10.2. No big deal, because you get clarity and precision, as well as a better depth and speration to your music. Comprimises are a part of music. I like the what the 7 offers, just trying to augment what it doesn't. I haev thought about the 10.2 as a woofer for 2 7.3's.
Hi Justin,
Yes, smaller Full-Rangers will usually extend in HF, larger will often do more in LF. The mid point for extension both ways is something I'm still exploring. Ideally, a cone diameter of around 90-mm to 120-mm is the likely candidate but what ever I do to extend the bandwidth, something else will have to given away, that's going to be power-handling. No free lunch.
I am currently experimenting with a 2000 micron neck-less cone to fit into the Alpair 12 frame. It should enter woofer-wide territory. But its early days as I'd like to reduce to 1500 microns.
Cheers
Mark.
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Soo... just a quick update of my findings. With living with a completed pair of Pensil 7.3's for the better part of a month, I find that the speakers tend to want to unload unnecessarily early. I.e. they want to reach peak Xmax long before I hit half of their RMS. I feel this is due to their cabinet design so in an effort to regain control of the cone movement, I'll be doing a sealed enclosure of around 9liters. I'll post my findings after they're done.
This of course leads me to have to use an external subwoofer or two which will not be a problem. I'll also be crossing the speakers over at 125hz with a 12db slope.
Any input?
This of course leads me to have to use an external subwoofer or two which will not be a problem. I'll also be crossing the speakers over at 125hz with a 12db slope.
Any input?
I'm really not sure. I'll be using the Dayton 240W plate amp so I could use two smaller woofers with an 8ohm impedance and low power handling (125w RMS) or I could use a single 4ohm woofer that matches the power output of the amp. I've considered a single CSS SDX10 but was once before plagued with room acoustics and not being able to place a single subwoofer in an optimal position. I'm feeling that 2 would help fill in room acoustic problems and further fill out the bottom end. I'm open to ideas for two woofers with low power handling in that impedance if anyone has any suggestions.
Hi Steve,
Something's amiss somewhere in the set-up. Possibly not enough damping material in the cabs? Or are yours in a large room the heavily damped? Amp friendly match? Can you post some pics of the inside of the cab, your room and set-up?
I've been running 7's in Pensil for the last 2 years at home, the driver's don't unload like your set-up. The Pensils 7's are popular, many examples around. Scott's design is one of the most efficient. Bass output should be generous with only little flicker from the cone on the lows.
Granted, if you need more bass, there's only so much a small driver can deliver.
Cheers
Mark.
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The 7.3 unloading is it getting input below the tuning frequency of the box. Pushing the box more toward aperiodic should help. The MarKen have at least of portion of that inherent in their design.
9 litres is the net volume of the dMK7.3*, you could take the ones you have and cut and stuff some open cel foam into the slots to push it more aperiodic.
6 and a bit litre gives butterworth Q.
Sealed does not improve power handling.It does increase acoustic loading and gives a slow continuous increase in load as you go down.
A high pass on the A7 does not increase the power handling, but does remove LF energy that can be distributed into the pass-band. ie at the same level the HPed A7 will have more termal reserves than the one without.
Woofer XO -- whatever works, 12 is good, the sealed sats will roll-off at the same rate (F3 9 litre sealed is ~95 hz). (ideal) Aperiodic 18dB/octave, vented (ie Pensil) 24dB/octave.
I'd use a pair of woofers... and each of those push-push if i can contrive it.
dave
* edit (it is buzzforb who already has dMK7.3)
9 litres is the net volume of the dMK7.3*, you could take the ones you have and cut and stuff some open cel foam into the slots to push it more aperiodic.
6 and a bit litre gives butterworth Q.
Sealed does not improve power handling.It does increase acoustic loading and gives a slow continuous increase in load as you go down.
A high pass on the A7 does not increase the power handling, but does remove LF energy that can be distributed into the pass-band. ie at the same level the HPed A7 will have more termal reserves than the one without.
Woofer XO -- whatever works, 12 is good, the sealed sats will roll-off at the same rate (F3 9 litre sealed is ~95 hz). (ideal) Aperiodic 18dB/octave, vented (ie Pensil) 24dB/octave.
I'd use a pair of woofers... and each of those push-push if i can contrive it.
dave
* edit (it is buzzforb who already has dMK7.3)
A significant difference is that Mark has a transformer coupled 300B vrs, IIRC, a well restored vintage Pioneer in Steve's case (Pioneer will have more extended LF response).
Like any 4th order system the Pensils will provide no load for the driver below tuning unless they are very heavily damped (ie aperiodic).
dave
I believe you're right Dave. It's unfortunate, and I have played with stuffing quite a bit. Perhaps my musical tastes just don't match up for what the Pensil has to offer. No doubt it's a great enclosure and a solid design, it just doesn't suit my needs and I believe a sealed enclosure at 9l will fit the bill nicely accompanied with multiple woofers.
I didn't mention it above, but another reason for redoing the cabinets is for some reason this custom color pigmented lacquer that I had mixed for me, is releasing odor, and has been for the last month. It's so strong that sitting in the listening room with them is absolute torture. I'll have to witch over to my regular method of finishing with the new cabinets.
All in all it's fantastic driver and really holds its own with some high dollar drivers but you're right Mark, there's only so much a small driver can do. I'm still a happy customer.
Thanks for the help fellas.
I didn't mention it above, but another reason for redoing the cabinets is for some reason this custom color pigmented lacquer that I had mixed for me, is releasing odor, and has been for the last month. It's so strong that sitting in the listening room with them is absolute torture. I'll have to witch over to my regular method of finishing with the new cabinets.
All in all it's fantastic driver and really holds its own with some high dollar drivers but you're right Mark, there's only so much a small driver can do. I'm still a happy customer.
Thanks for the help fellas.- Status
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