Well, I have heard some corner horns using single 8 inch drivers that really dug deep, and at good levels. Id've believed they were 15s.cujet said:
I guess there are some 8 inchers with low fs and high xmax, and there are plenty of two way 8 inch designs to vouch for the midrange performance.
I have used 8 inch woofers in a small room not far from the corners and found them to give me all I wanted. Maybe with a pair per side and some careful design they could work in your room.
Edit: I think that 400Hz is beginning to get high enough to leave the bass alone, it could even be higher. Appreciate, though, that if the crossover isn't carefully designed you'll have a rift in the midrange. Still though, the bass can remain satisfying. But as I said earlier, when designed carefully, any system can sound good (within reason
)Even very skilled people have failed at this
I would choose something like this
18" PRO woofer, this Selenium ought to work nice in closed or apperiodic, 180 USD
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-387
This well reputed and effective 8" Fostex, FF225K, 100 USD
http://www.madisound.com/pdf/fostexdrivers/ff225k.pdf
And a Fostex horn tweeter should be fine, maybe FT96H, 100 USD
http://www.madisound.com/pdf/fostexdrivers/ft96hrev.pdf
Total cost of all driver is around 800 USD
I reckon it will work with very simple filters
I would choose something like this
18" PRO woofer, this Selenium ought to work nice in closed or apperiodic, 180 USD
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-387
This well reputed and effective 8" Fostex, FF225K, 100 USD
http://www.madisound.com/pdf/fostexdrivers/ff225k.pdf
And a Fostex horn tweeter should be fine, maybe FT96H, 100 USD
http://www.madisound.com/pdf/fostexdrivers/ft96hrev.pdf
Total cost of all driver is around 800 USD
I reckon it will work with very simple filters
cujet said:
Can we assume that 8 to 10 cu ft is acceptable? A large box is needed because getting the levels that you're asking for from less than a 1 KW is difficult. You need a fairly efficient system. This large would probably be something like a Dunlavy tower layout:
http://www.stereophile.com/floorloudspeakers/162/index.html
My design for something this large, that I've not yet built, would be a 3 box system, 2 woofer boxes and a MT box, just to keep it modular and easier to build and move.
Are you familiar with the classic AR-9 speaker? I've not heard them but based on the AR family sound and the crossover design, I expect that they'd need to be revoiced. Here is a concept I came up with, you could obviously use less expensive drivers:
http://www.classicspeakerpages.net/...opic_id=5576&mesg_id=5576&listing_type=search
Are you willing to get a better amp than: "200WPC into 8ohm Adcom amp (325 into 4, which I prefer)"
Not necessarily expensive, a pro amp that will do more into 2 ohms, or even something used?
The problem with using 8" drivers, assuming that you really want a sealed box system, is that few have a free air resonance below 25 Hz and for a system like this you'd like to have the closed box resonance around 30 Hz which is difficult if not impossible if your woofer Fs is also close to 30 Hz.
I do like using 8" drivers, however I would use them vented.
If you go vented, you'll probably want to tune to 20 Hz, which means that for a B4 or B6 alignment, or a B6 less filter you'll want a driver with a free air resonance also of 20 Hz. However, you can often use alignment jamming to use a driver with a higher Fs.
Pete B.
Tinitus, you are even more crazy than I am!
I wonder if I have anywhere near enough power to drive a system like that to a proper concert level! Just kidding of course, 1400 watts of power handling is over the top!
I used to have a 15 inch pro driver setup with a large open baffle. Maybe 5x6 feet. It rocked out, but the sound was not Hi Fi. It really had colored sound.
Maybe, I am looking at this wrong, or describing it wrong. My previous example of my small den (12x12 feet) with my 6.5 MMT speakers had what I wanted in that room! It really had punch!
I was so disappointed when I moved to a larger house.
I want that back.
So, I assumed (yeah, I know) that a much larger version of what I have would do the trick. In my mind I scaled it up to dual 12 inch woofers.
Some really cool ideas I had not thought of, have been posted here. THANKS.
What about transmission lines? Is this a way to get more low extension out of smaller drivers? I had thought about a single 10 in a TL. Does this make any sense for my needs?
BHTX, I will look up what you suggest. I am not familiar with those drivers. Thanks!
Keep the suggestions coming.
Chris
I wonder if I have anywhere near enough power to drive a system like that to a proper concert level! Just kidding of course, 1400 watts of power handling is over the top!
I used to have a 15 inch pro driver setup with a large open baffle. Maybe 5x6 feet. It rocked out, but the sound was not Hi Fi. It really had colored sound.
Maybe, I am looking at this wrong, or describing it wrong. My previous example of my small den (12x12 feet) with my 6.5 MMT speakers had what I wanted in that room! It really had punch!
I was so disappointed when I moved to a larger house.
I want that back.
So, I assumed (yeah, I know) that a much larger version of what I have would do the trick. In my mind I scaled it up to dual 12 inch woofers.
Some really cool ideas I had not thought of, have been posted here. THANKS.
What about transmission lines? Is this a way to get more low extension out of smaller drivers? I had thought about a single 10 in a TL. Does this make any sense for my needs?
BHTX, I will look up what you suggest. I am not familiar with those drivers. Thanks!
Keep the suggestions coming.
Chris
Pete B,
Would you be willing to elaborate a bit on the following:
"which means that for a B4 or B6 alignment, or a B6 less filter you'll want a driver with a free air resonance also of 20 Hz. However, you can often use alignment jamming to use a driver with a higher Fs."
After reading your links, I am convinced I have looked at this wrong from the start. Sorry for not being clear in my original posts!
As I mentioned, I want to address a problem. Let's look at it from that point of view. I want the feel and sound of my old system in my new house with, maybe, a bit more punch. Higher quality would be nice too.
Chris
Would you be willing to elaborate a bit on the following:
"which means that for a B4 or B6 alignment, or a B6 less filter you'll want a driver with a free air resonance also of 20 Hz. However, you can often use alignment jamming to use a driver with a higher Fs."
After reading your links, I am convinced I have looked at this wrong from the start. Sorry for not being clear in my original posts!
As I mentioned, I want to address a problem. Let's look at it from that point of view. I want the feel and sound of my old system in my new house with, maybe, a bit more punch. Higher quality would be nice too.
Chris
The beauty of Thiele and Small (T&S) analysis is that the low end roll off of a woofer can be viewed as a traditional 2nd (sealed), 4th (vented), or 6th (vented + 2nd order boost filter) order high pass filter.
Are you familiar with the classical alignment tables for vented speaker systems? They're covered in Vance Dickason's "Loudspeaker Design Cookbook", do you have it?
You might be a bit more specific about your question so that I don't have to give a full tutorial about vented speaker design.
The Butterworth alignments are popular because they have maximally flat response in the passband, really not a big deal but it gives us a starting point when selecting a woofer. The B4 alignment is interesting because the box tuning Fb is equal to the driver Fs which is also the -3dB point or F3 of the system. You should tune to the lowest frequency of interest for which the driver has enough Vd to support the required peak Xmax at about 1.4 times Fb.
Another interesting B4 characteristic is that the box volume is equal to the Vas of the driver. The last requirement to obtain a B4 alignment is to have the correct Qts, ideally you'll start with a driver lower than required, and choose the passive crossover components DC resistance so that the final system has the correct Qts. You're going to need a fairly large inductor on that woofer so allocate about .5 to 1 ohm for the inductor. Interesting, that this would allow you to put two 4 - 6 ohm drivers in parallel, then adding the inductor R end up with a 3 to 4 ohm system impedance that many amps can handle.
You'll find that many large drivers require a huge box for a B4 alignment which leads us to a B6 where we reduce the box size by one half and provide an electrical +6 dB boost filter at Fb to make up for the lost output. We loose 6 dB of output at Fb by reducing the box size to 1/2. The system is down -9 dB without the filter.
There is something interesting here, the boundaries of the room provide some boost at very low frequencies and - 9 dB at 20 Hz is often just fine, sometimes even more natural sounding than -3dB at 20 Hz. It is often fine to run a low tuned B6 system without the filter.
The rolloff is much more gradual with a B6 less filter and it is close to a QB3 alignment which has better transient response that many claim is so important. The bass transient response should be reasonably good, but not as heavily damped as some claim is required IMO. Cavity midbass resonances are a bigger issue IMO.
There is obviously a continum, you could go in between a B4 and B6 depending on how much output you're willing to give up at Fb.
The legendary B&W801 was a 12" vented B6 system tuned to 20 Hz and many preferred it without the boost filter.
http://www.stereophile.com/floorloudspeakers/506/
The PSB Stratus Gold I believe claims to be a B4 alignment tuned to 28 Hz.
I believe that the Paradigm Studio 100 is a B4 tunded to 20 Hz:
http://www.stereophile.com/floorloudspeakers/252/
Alignment jamming was covered in the AES. Let's say you find a driver that looks good but the Fs is 30 Hz rather than 20, simulate it in the B4 tuned to 20 and see how far off the amplitude response is, often it is not far off and will work just fine.
Be sure to provide baffle step compensation in your crossover.
And be sure to use a large port to minimize port vent losses if you go vented.
Been a long time since I gave this lecture, LOL!
Pete B.
Are you familiar with the classical alignment tables for vented speaker systems? They're covered in Vance Dickason's "Loudspeaker Design Cookbook", do you have it?
You might be a bit more specific about your question so that I don't have to give a full tutorial about vented speaker design.
The Butterworth alignments are popular because they have maximally flat response in the passband, really not a big deal but it gives us a starting point when selecting a woofer. The B4 alignment is interesting because the box tuning Fb is equal to the driver Fs which is also the -3dB point or F3 of the system. You should tune to the lowest frequency of interest for which the driver has enough Vd to support the required peak Xmax at about 1.4 times Fb.
Another interesting B4 characteristic is that the box volume is equal to the Vas of the driver. The last requirement to obtain a B4 alignment is to have the correct Qts, ideally you'll start with a driver lower than required, and choose the passive crossover components DC resistance so that the final system has the correct Qts. You're going to need a fairly large inductor on that woofer so allocate about .5 to 1 ohm for the inductor. Interesting, that this would allow you to put two 4 - 6 ohm drivers in parallel, then adding the inductor R end up with a 3 to 4 ohm system impedance that many amps can handle.
You'll find that many large drivers require a huge box for a B4 alignment which leads us to a B6 where we reduce the box size by one half and provide an electrical +6 dB boost filter at Fb to make up for the lost output. We loose 6 dB of output at Fb by reducing the box size to 1/2. The system is down -9 dB without the filter.
There is something interesting here, the boundaries of the room provide some boost at very low frequencies and - 9 dB at 20 Hz is often just fine, sometimes even more natural sounding than -3dB at 20 Hz. It is often fine to run a low tuned B6 system without the filter.
The rolloff is much more gradual with a B6 less filter and it is close to a QB3 alignment which has better transient response that many claim is so important. The bass transient response should be reasonably good, but not as heavily damped as some claim is required IMO. Cavity midbass resonances are a bigger issue IMO.
There is obviously a continum, you could go in between a B4 and B6 depending on how much output you're willing to give up at Fb.
The legendary B&W801 was a 12" vented B6 system tuned to 20 Hz and many preferred it without the boost filter.
http://www.stereophile.com/floorloudspeakers/506/
The PSB Stratus Gold I believe claims to be a B4 alignment tuned to 28 Hz.
I believe that the Paradigm Studio 100 is a B4 tunded to 20 Hz:
http://www.stereophile.com/floorloudspeakers/252/
Alignment jamming was covered in the AES. Let's say you find a driver that looks good but the Fs is 30 Hz rather than 20, simulate it in the B4 tuned to 20 and see how far off the amplitude response is, often it is not far off and will work just fine.
Be sure to provide baffle step compensation in your crossover.
And be sure to use a large port to minimize port vent losses if you go vented.
Been a long time since I gave this lecture, LOL!
Pete B.
I'd go with a pair of these per side, warning I've not tried them myself:
http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=290-570
This for a mid, looks good on paper, warning again I've not tried it:
http://www.partsexpress.com/pe/pshowdetl.cfm?Partnumber=294-651
And the tweeter previously mentioned which I use in my own system.
Another outstanding tweeter with a small face plate, check Zaph's tests to see the remarkable CSD plot and all around excellent performance:
http://www.madisound.com/catalog/product_info.php?manufacturers_id=153&products_id=1078
You could even use a pair per side since the small face plate allows for tight driver to driver spacing.
Pete B.
http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=290-570
This for a mid, looks good on paper, warning again I've not tried it:
http://www.partsexpress.com/pe/pshowdetl.cfm?Partnumber=294-651
And the tweeter previously mentioned which I use in my own system.
Another outstanding tweeter with a small face plate, check Zaph's tests to see the remarkable CSD plot and all around excellent performance:
http://www.madisound.com/catalog/product_info.php?manufacturers_id=153&products_id=1078
You could even use a pair per side since the small face plate allows for tight driver to driver spacing.
Pete B.
PHL 1120 might be a better choice for the midrange, both have some response roughness/peaking that you have to take into consideration:
http://www.akkus.com.pl/index.php?grupa=gl_szczegoly&firma=phl&model=1120&lang=pl&dh=dt
http://www.akkus.com.pl/index.php?grupa=gl_szczegoly&firma=phl&model=1120&lang=pl&dh=dt
..after going through this thread a little (..why I don't know), still the best suggestion was the one he was given previously - the Dayton HiFi sub drivers. Well, that is IF you still need fairly high output, moderately low enclosure volume, good extension vs. spl/eff. - all in a sealed enclosure without eq.. Dave's CSS suggestion is also a good one, though it is about 5db less efficient.
Frankly cuejet, like many posters, I think you are being unrealistic with what you desire - mechanically speaking. (..hey, I want it "all" to - its just that I realize what works and what doesn't )
If we "look" at what you want the most first - "punch", THEN we have a starting point for analysis.
Punch happens anywhere between about 60 Hz and 300 Hz. The effect seems to be "enhanced" by:
1. sealed enclosures
2. high eff. drivers with moderate mass and high force.
Note that pretty much ALL of the above is counter to most drivers that would *try* to give you it "all".
*HINT*
To get what you want (at least with "punch" as the dominate attribute), then you should be looking for a pro midbass driver - NOT a "do-it-all" driver (in combination with a sealed enclosure) that doesn't do *anything* really well.
Still, it isn't at all easy to find a pro midbass that doesn't rapidly reduce in spl's below 150 Hz with even a generous enclosure volume.
Basically you are looking for a fairly high fs driver with both a relatively high mechanical *and* electrical "compliance" (qm and qe respectively). Note that a high "qe" is counter to higher eff. and greater force (..which is why its difficult to find such a driver). Whats worse is that you also want decent linear excursion.
After a LOT of searching - there is such a driver (its new).
The Ciare (OEM) 10-2.5 (under Neodymium LF Speakers):
http://www.ciare.com/oem_new/index_en.html
(assistance audio should be able to sell them at reasonable cost)
Use two per side. Each should be "encapsulated" in their own sealed enclosure. Volume for each should be about 25 liters. Moreover, the enclosure structure should be in the shape of a pipe with the driver at one end and the other end closed (..this will reduce odd-order non-linear distortion). NO "stuffing". Placement should be near the floor with one on top of the other (similar to a Wilson Audio Watt Puppy). Place a "box" (a normal looking rectangular enclosure) "around" the pipes and fill that volume with sand (i.e. between the "box" and the pipes).
Drivers should be connected in parallel (4 ohm nominal) - and with your low output impedance amp should generate almost another +6db. This gain (with floor boundary gain and room gain) should be more than enough to compensate for not only baffle step reduction, but also provide for a fair bit of eq. *shelving* to match with a normal eff. midrange driver. (..do some modeling to see what I'm talking about here.)
*THAT* should get you what you really want ..minus the low freq. extension that is better suited to a different driver in a different configuration.
Frankly cuejet, like many posters, I think you are being unrealistic with what you desire - mechanically speaking. (..hey, I want it "all" to - its just that I realize what works and what doesn't
)If we "look" at what you want the most first - "punch", THEN we have a starting point for analysis.
Punch happens anywhere between about 60 Hz and 300 Hz. The effect seems to be "enhanced" by:
1. sealed enclosures
2. high eff. drivers with moderate mass and high force.
Note that pretty much ALL of the above is counter to most drivers that would *try* to give you it "all".
*HINT*
To get what you want (at least with "punch" as the dominate attribute), then you should be looking for a pro midbass driver - NOT a "do-it-all" driver (in combination with a sealed enclosure) that doesn't do *anything* really well.
Still, it isn't at all easy to find a pro midbass that doesn't rapidly reduce in spl's below 150 Hz with even a generous enclosure volume.
Basically you are looking for a fairly high fs driver with both a relatively high mechanical *and* electrical "compliance" (qm and qe respectively). Note that a high "qe" is counter to higher eff. and greater force (..which is why its difficult to find such a driver). Whats worse is that you also want decent linear excursion.
After a LOT of searching - there is such a driver (its new).
The Ciare (OEM) 10-2.5 (under Neodymium LF Speakers):
http://www.ciare.com/oem_new/index_en.html
(assistance audio should be able to sell them at reasonable cost)
Use two per side. Each should be "encapsulated" in their own sealed enclosure. Volume for each should be about 25 liters. Moreover, the enclosure structure should be in the shape of a pipe with the driver at one end and the other end closed (..this will reduce odd-order non-linear distortion). NO "stuffing". Placement should be near the floor with one on top of the other (similar to a Wilson Audio Watt Puppy). Place a "box" (a normal looking rectangular enclosure) "around" the pipes and fill that volume with sand (i.e. between the "box" and the pipes).
Drivers should be connected in parallel (4 ohm nominal) - and with your low output impedance amp should generate almost another +6db. This gain (with floor boundary gain and room gain) should be more than enough to compensate for not only baffle step reduction, but also provide for a fair bit of eq. *shelving* to match with a normal eff. midrange driver. (..do some modeling to see what I'm talking about here.)
*THAT* should get you what you really want ..minus the low freq. extension that is better suited to a different driver in a different configuration.
I was just thinking about what Scott offers above here and let me offer a slightly different perspective.
I see that there are two aspects to "punch" the kick in the chest, that might also shake the floor and walls, and the overtones that provide the sharpness and snap to it. What Scott describes will give you punch without the kick, whereas what I describe will give you it all, almost anyway.
You asked for what I see as a large system, and I expect a large system to do 20 Hz. I took your punch to be punch *and* the low bass kick.
Another thing to consider is that you want to put the midrange in a small enclosure, choose the size to raise Fc to 200-300 Hz, whereever you want your crossover. This will form one section of a fourth order LR crossover and you want the Qtc to be ideally .707, or higher to also provide some baffle step compensation. Series R in the pad on the mid will also help raise Qtc.
Pete B.
I see that there are two aspects to "punch" the kick in the chest, that might also shake the floor and walls, and the overtones that provide the sharpness and snap to it. What Scott describes will give you punch without the kick, whereas what I describe will give you it all, almost anyway.
You asked for what I see as a large system, and I expect a large system to do 20 Hz. I took your punch to be punch *and* the low bass kick.
Another thing to consider is that you want to put the midrange in a small enclosure, choose the size to raise Fc to 200-300 Hz, whereever you want your crossover. This will form one section of a fourth order LR crossover and you want the Qtc to be ideally .707, or higher to also provide some baffle step compensation. Series R in the pad on the mid will also help raise Qtc.
Pete B.
PB2 said:
It will provide "kick" as well, remember this should be viewed as an overall design. I.E. using a shelving filter and drop the eff. at 100+ Hz down to about 89 db net (1 watt 1 meter) will provide a fair bit of extension, especially considering room gain. Its just something you really need to model to "see".
It will even do some low freq. (below 40 Hz) "room lock" or "slam" as well - just at a lower spl (..relative to the average). Really though, thats something for a dedicated sub-woofer to supply (..and a VERY good one at that).
Well, great!
That is a lot to digest. I will take some time and review all the above suggestions. Including the HiFi Dayton sub suggestion. It is great to have so many folks with different perspectives! THANKS!
The descriptions are accurate, and the punch I am looking for is an overall excellent low freq extension with the slightly higher overtones accurate and sharp.
As I mentioned, the 6.5's have it in a small room.
Back to my other question, how about a TL? (never heard one other than Bose)
Chris
That is a lot to digest. I will take some time and review all the above suggestions. Including the HiFi Dayton sub suggestion. It is great to have so many folks with different perspectives! THANKS!
The descriptions are accurate, and the punch I am looking for is an overall excellent low freq extension with the slightly higher overtones accurate and sharp.
As I mentioned, the 6.5's have it in a small room.
Back to my other question, how about a TL? (never heard one other than Bose)
Chris
cujet,
You asked about a transmission line. These are traditionally thought to be able to get extension out of a small driver. More modern thinking suggests they behave more like a well dampded closed box when aligned properly. Short answer - (IMO) more for sound quality, good for a different project perhaps.
ScottG suggests 60-300Hz and this strikes me as the room resonance region. Perhaps half your issue is room placement, including your seated location and the effect of the speakers you build within your room. Dipoles are known for overcoming room resonances They are not so easy to build for bass, but maybe midrange if it goes into this region.
You asked about a transmission line. These are traditionally thought to be able to get extension out of a small driver. More modern thinking suggests they behave more like a well dampded closed box when aligned properly. Short answer - (IMO) more for sound quality, good for a different project perhaps.
ScottG suggests 60-300Hz and this strikes me as the room resonance region. Perhaps half your issue is room placement, including your seated location and the effect of the speakers you build within your room. Dipoles are known for overcoming room resonances They are not so easy to build for bass, but maybe midrange if it goes into this region.
More crazy stuff !
Theres a bargain on this 15" Usher Studio woofer, looks like half price, but it may need BR vented box design ... how about two of them pr side
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=296-630
This midrange looks quite good
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=294-652
Tweeter, well a good efficient ribbon would be the obvious choise, makes a lower xo point possible
Theres a bargain on this 15" Usher Studio woofer, looks like half price, but it may need BR vented box design ... how about two of them pr side
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=296-630
This midrange looks quite good
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=294-652
Tweeter, well a good efficient ribbon would be the obvious choise, makes a lower xo point possible
cujet said:
For a subwoofer - yes.. for a heavy mass mid (or midbass) with lots of stuffing - yes, otherwise don't consider it.
The LAB12's look well suited to a T-line type SUB design. Perhaps a simple BIB?
http://www.diyaudio.com/forums/showthread.php?s=&threadid=66173
http://www.zillaspeak.com/BibBassHorns.asp
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