good day,
i am attempting to design bass modules - i hesitate to call them subwoofers, as i'm not looking for REALLY low extension - to extend the range of my monitor speakers in my 2 channel audio system. the cabinets will be sealed and need to be pretty compact, a close estimate on volume is around 17 L (~1000 ft3). i'm hoping for strong output from around 35 hz - 80 hz, and based on my reading, a Qtc not in excess of 0.65 (which i'm finding difficult given the cabinet size, even if i factor in polyfill).
i've entered the data for around 40 drivers in the 8" - 10" range into WinISD and have been analyzing the results to determine the best options. there are some speakers like the ScanSpeak 23W/4557T that have extraordinary output (-3db at 35 hz in a 17 L sealed box), however, the Qtc is 0.89, which i've read will be boomy sounding (great for theater, less ideal for music). Then there are drivers like the Acoustic Elegance TD10M which yield a system Q of 0.51, however, have rather limited extension (-18 db at 35 hz).
the way i'm evaluating suitability of drivers is to find one that offers reasonable extension and a low Qtc value. using the WinISD program, i'm recording the Qtc value at 17 L and 22 L (22 accounts for polyfill) and the -3db, -6db, and -10db frequencies, as well as the output at 35 hz.
is this a reasonable approach?
are there other variables i should be looking into, too?
what targets should i be shooting for where the Qtc, -3db, -6db, -10db, and 35 hz results are concerned?
this is my first time at attempting anything like this, and i've got a pile of data - i'm just unsure how to interpret it to make a reasonable decision. HELP!!!
any inputs would be MUCH appreciated.
i am attempting to design bass modules - i hesitate to call them subwoofers, as i'm not looking for REALLY low extension - to extend the range of my monitor speakers in my 2 channel audio system. the cabinets will be sealed and need to be pretty compact, a close estimate on volume is around 17 L (~1000 ft3). i'm hoping for strong output from around 35 hz - 80 hz, and based on my reading, a Qtc not in excess of 0.65 (which i'm finding difficult given the cabinet size, even if i factor in polyfill).
i've entered the data for around 40 drivers in the 8" - 10" range into WinISD and have been analyzing the results to determine the best options. there are some speakers like the ScanSpeak 23W/4557T that have extraordinary output (-3db at 35 hz in a 17 L sealed box), however, the Qtc is 0.89, which i've read will be boomy sounding (great for theater, less ideal for music). Then there are drivers like the Acoustic Elegance TD10M which yield a system Q of 0.51, however, have rather limited extension (-18 db at 35 hz).
the way i'm evaluating suitability of drivers is to find one that offers reasonable extension and a low Qtc value. using the WinISD program, i'm recording the Qtc value at 17 L and 22 L (22 accounts for polyfill) and the -3db, -6db, and -10db frequencies, as well as the output at 35 hz.
is this a reasonable approach?
are there other variables i should be looking into, too?
what targets should i be shooting for where the Qtc, -3db, -6db, -10db, and 35 hz results are concerned?
this is my first time at attempting anything like this, and i've got a pile of data - i'm just unsure how to interpret it to make a reasonable decision. HELP!!!
any inputs would be MUCH appreciated.
my main amps are 70 WPC tube monos; speakers are 91 db efficient monitors that play down to 60 hz; room is 16 ft x 18 ft.
my plan is to high pass the mains / low pass the subs at around 80 hz. i am not limited by cabinet type (sealed, etc), but am limited by cabinet size - the width can not be much more than 12", the dept can not be much more than 18", the height can not exceed 10". i'd like to keep them as short as possible, so if a 10" driver is used, they would need to be downfiring (an 8" driver could be down or frontfiring).
thanks for any inputs.
so... maximum working volume of .73 ft^3 huh. super mini sub, i like. 
two of these in series would be ok and very inexpensive. 6-1/2" Subwoofer Speaker 299-114
edit: wait... you're not trying to pressurize a room that size with drivers that small are you ?
two of these in series would be ok and very inexpensive. 6-1/2" Subwoofer Speaker 299-114
edit: wait... you're not trying to pressurize a room that size with drivers that small are you ?
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In EU terms your room is 4,9m x 5,5m and the maximum outer dimensions of the sub is roughly 30x48x25cm (wxdxh). To make things simple, we could say you use 20mm MDF sheets for the cabinet building. That would leave internal dimensions of 26x44x21cm which corresponds to 24l. I would say that your 17l might be a tad on the conservative side (including space for bracings and driver). Doesn't matter really - the volume is small, but there is hope - at some cost
You mentioned that you are attempting to design bass modules. I read that as you could allow at least two of these babies?
Also, I read between the lines that you are going to use separate sub/bass amp(s)?
Another thing - you should decide for what maximum sound pressure you are designing for. I assume your main speakers with the tube amp have the capacity of producing some 110dB. My recommendation would be to to design for your maximum expected sound pressure and then add some (minimum) 6dB headroom.
To achieve loud distortion free bass in such small cabinets there are in principle only two practical alternatives:
1. Sealed cabinet... needs a driver that have huge xmax and your would also need massive amount of power. Long throw high power woofers are very demanding to make good and it often costs a lot, but parts-express sells the TC Sounds Epic 10 at a nice price. You could pair this one with a 500-1000W class D amp. Eq-ing the lower octaves and using a subsonic filtre should leave you high quality bass at some 102dB/30Hz in room (two subs and you get 108dB). You even have plenty of headroom within these data. If you get hold on second hand Audiopulse RV10D2 you even have a better driver with a very linear motor suffering little from power compression.
2. Passive radiator... substitutes BR loading. Challenge with BR loading is two-folded. When designing a BR loaded cabinet the port tuning should be set as low as possible to avoid poor impulse response and to leave Group Delay into the none audible region. A nice start would be a port tuning of about 20Hz, but in such small cabinet the port would be extremely long. The solution is to use passive radiator. This is more or less the same as using a BR-loading, but you should keep the tuning frequency of the passive radiator(s) as low as possible. You gain increased sensitivity, lowers xmax and/or can use a smaller power amp. There are several drivers that could be put in a small cabinet for this purpose, but you could try simulating with the brand new Seas L26RO4Y and report the results
I would recommend you to google and download the Excel sheet Unibox made by Kristian Ougaard. It is very easy to use and you can model SC/BR/PR cabinets in paralell. The BR modelling is pretty good. Simple and free Later you could install more advanced software.
You mentioned that you are attempting to design bass modules. I read that as you could allow at least two of these babies?
Also, I read between the lines that you are going to use separate sub/bass amp(s)?
Another thing - you should decide for what maximum sound pressure you are designing for. I assume your main speakers with the tube amp have the capacity of producing some 110dB. My recommendation would be to to design for your maximum expected sound pressure and then add some (minimum) 6dB headroom.
To achieve loud distortion free bass in such small cabinets there are in principle only two practical alternatives:
1. Sealed cabinet... needs a driver that have huge xmax and your would also need massive amount of power. Long throw high power woofers are very demanding to make good and it often costs a lot, but parts-express sells the TC Sounds Epic 10 at a nice price. You could pair this one with a 500-1000W class D amp. Eq-ing the lower octaves and using a subsonic filtre should leave you high quality bass at some 102dB/30Hz in room (two subs and you get 108dB). You even have plenty of headroom within these data. If you get hold on second hand Audiopulse RV10D2 you even have a better driver with a very linear motor suffering little from power compression.
2. Passive radiator... substitutes BR loading. Challenge with BR loading is two-folded. When designing a BR loaded cabinet the port tuning should be set as low as possible to avoid poor impulse response and to leave Group Delay into the none audible region. A nice start would be a port tuning of about 20Hz, but in such small cabinet the port would be extremely long. The solution is to use passive radiator. This is more or less the same as using a BR-loading, but you should keep the tuning frequency of the passive radiator(s) as low as possible. You gain increased sensitivity, lowers xmax and/or can use a smaller power amp. There are several drivers that could be put in a small cabinet for this purpose, but you could try simulating with the brand new Seas L26RO4Y and report the results
I would recommend you to google and download the Excel sheet Unibox made by Kristian Ougaard. It is very easy to use and you can model SC/BR/PR cabinets in paralell. The BR modelling is pretty good. Simple and free
Later you could install more advanced software.
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so... maximum working volume of .73 ft^3 huh. super mini sub, i like.
two of these in series would be ok and very inexpensive. 6-1/2" Subwoofer Speaker 299-114
edit: wait... you're not trying to pressurize a room that size with drivers that small are you ?
super mini - YES!
sub - well, as close as i can get given the diminutive cabinets.
i'm just trying to add as much bottom end as i can to my monitors. they are wilson audio watts, and play very nicely down to the mid to upper 50's... i'm hoping by adding a pair of 'bass modules' under each (like a mini puppy) i can improve the low end.
i've checked 40+ drivers in WinISD to see which will give me the best extension and strongest output while maintaining low Qtc. using these variables, i've identified several options - it's just a matter of determining what the right balance is between Qtc, Extension, and Output. are there other variables that i should consider, such as Xmax or Le, that will help narrow in on the best option?
here's my 'short list' so far...
An externally hosted image should be here but it was not working when we last tested it.
@ Tytte71...
thanks so much for the detailed response. yes, the plan is to make two of these 'little' subs - one to pair with each of my monitors. and yes, you have surmised properly that i will be using separate amplification. my initial plan was to mount a compact plate amp onto each cabinet - the 300 W O Audio plate amp is small enough to fit nicely, though it sounds as if more power might be necessary.
"long throw, high power woofers" - does this mean i should be looking for a driver with high Xmax and Pe specifications?
thanks so much for the detailed response. yes, the plan is to make two of these 'little' subs - one to pair with each of my monitors. and yes, you have surmised properly that i will be using separate amplification. my initial plan was to mount a compact plate amp onto each cabinet - the 300 W O Audio plate amp is small enough to fit nicely, though it sounds as if more power might be necessary.
"long throw, high power woofers" - does this mean i should be looking for a driver with high Xmax and Pe specifications?
High xmax/Pe is important, especially for subs in small cabinets- otherwise they will run out of juice pretty early.
It looks like you have got a very nice amp/main speaker setup, so I would recommend making subs that justifies the setup. 300W could be fine when dealing with passive radiator (or BR) systems, but for sealed cabinet it may become a little on the low side.
There are some other factors you should also keep in mind;
The motor system is important for concluding on the capacity. Unfortunately most (hifi driver) manufacturers don't show large signal analysis in their data sheets.
What happens is that as you increase power and consequently the stroke increases, the motor becomes more and more asymetric (behaves different in the +/- direction) and non linear. Have a look at e.g. Dayton Titanic woofer at Parts-express... PE shows some large signal analysis for these drivers.
Also imagine that you have a driver that is 1% efficient (which is fairly high for these kind of drivers). This implies for each 100W that is fed into the driver, 1W is converted to sound effect while 99W have to disipate as heat in the voice coil arrangement. Heat can severly affect the linearity of the motor and lead to thermal compression.
Selecting a subwoofer with high power capacity is a good rule of thumb. Look at typical high power woofers and study voice coil construction, choice of voice coil former, how the gap and shortening rings are arranged, etc.
In these very small chambered cabinets with high stroke drivers, the cabinet pressure will soon be pretty high. Sealed cabinets deals with high pressure but it gets even worse with BR and passive radiator systems. To avoid deformation of the woofer diaphragm, ultra stiff diaphragm is needed. Therefore aluminium diaphragmis is often preferred on these kind of drivers. Alu is also good for distributing heat from the voice coil. High pressurised subs demands very rigid cabinets. Don't save money on glue, srews or other remedies that hold it together
Then, some woofers are quite, others not. With this I mean there are some woofers that makes eigen sound when pushed heavily at low frequencies. This is also information that rarely can be found at manufacturers' sites.
Conclusion to this... little is found in manufacurers data - ask for others experience with specific drivers and you have a much better chance to succeed on first try
Hi,
Wilson Audio WATTs are nearfield monitors. They not accurate farfield
if used on stands away from walls. Placing near boundaries improves
matters bass wise but messes up nearly everything else.
The PUPPY is not just a subwoofer, it works in parallel with the WATT
to turn it into a farfield monitor. Adding a sub here as described isn't
going to address this fundamental issue.
See : A Speaker project it shows the general principle.
and the stereophile measurements section for the various Watt/Puppy
versions, you'll see its not really that simple as the above implies.
What you need first IMO is something like this on the amplifier input :
Baffle Step Compensation
Figure 3 - The Baffle Step Correction Circuit
Yuo can try and make your subs do what the PUPPYs do,
but the above seems a simpler and more flexible solution.
Stereophile indicates the WATTs are tuned to 40Hz.
Unless high bass volumes are an issue REL recommend running the
main speakers full range, and for valve amplifiers running their
subs from the outputs taps of the amplifier, not a line level.
REL Acoustics : Great Britain's most acclaimed Sub Bass Systems click on "pro's".
You really should be using WinISDPro to model excursion and power.
Driver parameters don't really tell the whole story, especially distortion.
See the Dayton 8" here : Zaph|Audio
Dayton Audio RSS210HF-4 8" Reference HF Subwoofer 4 Ohm 295-456
Should suit your case, using a well stuffed sealed box.
Carefully model and choose your the correct sub amplifier, make
sure it can be set low enough if the WATTs are run full range.
Note that its possible to EQ the sub to any response within its limits,
and many real world subs use this approach, read up on Linkwitz
Transforms, loads of power in small boxes is used to extend the
bass by EQ. Note Max SPL sealed depends on driver size and
excursion only, as long as you have enough power.
e.g. see Pluto + subwoofer
rgds, sreten.
Wilson Audio WATTs are nearfield monitors. They not accurate farfield
if used on stands away from walls. Placing near boundaries improves
matters bass wise but messes up nearly everything else.
The PUPPY is not just a subwoofer, it works in parallel with the WATT
to turn it into a farfield monitor. Adding a sub here as described isn't
going to address this fundamental issue.
An externally hosted image should be here but it was not working when we last tested it.
See : A Speaker project it shows the general principle.
and the stereophile measurements section for the various Watt/Puppy
versions, you'll see its not really that simple as the above implies.
What you need first IMO is something like this on the amplifier input :
Baffle Step Compensation
An externally hosted image should be here but it was not working when we last tested it.
Figure 3 - The Baffle Step Correction Circuit
Yuo can try and make your subs do what the PUPPYs do,
but the above seems a simpler and more flexible solution.
Stereophile indicates the WATTs are tuned to 40Hz.
Unless high bass volumes are an issue REL recommend running the
main speakers full range, and for valve amplifiers running their
subs from the outputs taps of the amplifier, not a line level.
REL Acoustics : Great Britain's most acclaimed Sub Bass Systems click on "pro's".
You really should be using WinISDPro to model excursion and power.
Driver parameters don't really tell the whole story, especially distortion.
See the Dayton 8" here : Zaph|Audio
Dayton Audio RSS210HF-4 8" Reference HF Subwoofer 4 Ohm 295-456
Should suit your case, using a well stuffed sealed box.
Carefully model and choose your the correct sub amplifier, make
sure it can be set low enough if the WATTs are run full range.
Note that its possible to EQ the sub to any response within its limits,
and many real world subs use this approach, read up on Linkwitz
Transforms, loads of power in small boxes is used to extend the
bass by EQ. Note Max SPL sealed depends on driver size and
excursion only, as long as you have enough power.
e.g. see Pluto + subwoofer
rgds, sreten.
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sreten, I always enjoy reading your posts due to your wide theoretical knowledge and practical experience.
I concider your info about the original watt/puppy integration very valuable here. But, based on my own experience/preferences - and for the first time - I might have to disagree with you on your woofer recommendation
If srosenberg listens to bass demanding music at modest levels, then yes I agree - 8" woofers in sealed enclosures might be ok. But if he enjoys playing at a little more than at modest levels I would not spend my money on this setup, unless I was allowed to use more than two drivers. The 8"-ers will in a sealed enclosure soon exceed its stroke range if used as low as 30Hz. Maybe I could live with this size/kind of driver in a BR/PR alignment.
It would be interesting to hear your arguments for not scaling the system as my proposals in previous posts (there is off course the cost aspect here ...).
By the way; Wavecor have a very nice 8" driver (SW223BD01) that is suitable for small PR enclosures. It has a well built motor designed for sub woofer use and delivers in addition one of the cleanest (lower/mid) midranges I have ever seen from an 8" driver (ref. to measurements done by Hobby hifi)... could maybe also an alternative if watt/puppy integration is to be done the Wilson way?
A little off topic: Currently I use two Peerless SLS 12" subwoofer drivers (xmax 8mm) in sealed enclosures, squeezing them to 25Hz (DRC controlled with the subs corner/wall placed). This arrangement is simply not enough for my use and living room (a few square meters larger than srosenberg's) and will be replaced by a setup delivering 15dB more output. No I will not play that much louder, but in addition to a few dB more I also need some headroom.
I concider your info about the original watt/puppy integration very valuable here. But, based on my own experience/preferences - and for the first time - I might have to disagree with you on your woofer recommendation
If srosenberg listens to bass demanding music at modest levels, then yes I agree - 8" woofers in sealed enclosures might be ok. But if he enjoys playing at a little more than at modest levels I would not spend my money on this setup, unless I was allowed to use more than two drivers. The 8"-ers will in a sealed enclosure soon exceed its stroke range if used as low as 30Hz. Maybe I could live with this size/kind of driver in a BR/PR alignment.
It would be interesting to hear your arguments for not scaling the system as my proposals in previous posts (there is off course the cost aspect here ...).
By the way; Wavecor have a very nice 8" driver (SW223BD01) that is suitable for small PR enclosures. It has a well built motor designed for sub woofer use and delivers in addition one of the cleanest (lower/mid) midranges I have ever seen from an 8" driver (ref. to measurements done by Hobby hifi)... could maybe also an alternative if watt/puppy integration is to be done the Wilson way?
A little off topic: Currently I use two Peerless SLS 12" subwoofer drivers (xmax 8mm) in sealed enclosures, squeezing them to 25Hz (DRC controlled with the subs corner/wall placed). This arrangement is simply not enough for my use and living room (a few square meters larger than srosenberg's) and will be replaced by a setup delivering 15dB more output. No I will not play that much louder, but in addition to a few dB more I also need some headroom.
- and for the first time - I might have to disagree with you on your woofer recommendation
I
Hi,
If you read carefully what I said I'm suggesting running the WATTs fullrange
with line level BSC correction, consequently the sub will be crossed over very
low. Given the OP's size constraints an 8" in a normal box or possibly a 10"
to 12" in a Linkwitz Transform arrangement with more power are the options.
The lower you cross a sub, the less it needs to do, overall.
Like I said, careful modelling of driver excursion for Max SPL and required
power is needed. Max SPL only depends on driver size and excursion if you
have enough power. Overall bass levels would be limited by the WATTs in
the above arrangement, how low you can go by the extra subs limits.
YMMV but given the volumes of of the two sealed boxes, that driver suits
well IMO, I can't think of anything better for a normal sealed alignment.
rgds, sreten.
thanks all for your considered commentary - your comments have been extremely educational for me.
the article A Speaker Project was a great read - LOTS of important information therein. the Baffle Step Compensation suggestion is a great one - i'm going to look into having something like that assembled into a small box that i can run my IC's through on the way to the power amp for the Watts. and also thanks for pointing me to the stereophile review of the Watt/Puppy. on reviewing the measurements noted here, i'm actually rethinking the project a little. Of note are the following observations...
"the WATT's bass is lightweight when used without the Puppy, the rear-facing port only adding marginal reinforcement below 70Hz or so."
"The Puppy woofer can be seen actually to cover just a relatively small region in the mid–upper-bass, from 62Hz to 152Hz, to judge by the –6dB points. The minimum in the woofer output at 28Hz confirms the port tuning"
"an important effect on the sound of the WATT [when used with the Puppy] will be to reduce the stress on the latter's 6.5" woofer, allowing a higher playback level before audible strain sets in."
if i'm interpreting the analysis correctly (highly unlikely), i may have been overestimating the low end achieved by the puppy. where the puppy is concerned, seemingly it's designed to operate from 62 Hz to 152 Hz.
given this, does it seem reasonable to high pass the Watts (to relieve stress on the 6.5" woofer), and low pass the bass modules i'm considering building, higher than my original estimate of 80 Hz... perhaps as high as 100 Hz, assuming they are capable of sounding good that high? sreten mentioned letting the Watts go full range... sounds like there's a case to be made for both arrangements.
additionally, i presume that i do not need strong output down to the mid 30's to approximate the low end of the puppys, but rather the mid 50's would get me close (blue trace, figure 8... the puppy is -10 db at 50 hz). That opens up my options where drivers are concerned, and enables me to consider some of the models that yielded lower Qtc values, but correspondingly less extension.
what would be a good target range for Qtc for these bass modules? i've read 0.7 is neutral, with as low as 0.5 being acceptable when tight, controlled bass is desired. any suggestions for an appropriate Qtc value would be appreciated.
thanks again for your willingness to share your knowledge - it's REALLY appreciated.
the article A Speaker Project was a great read - LOTS of important information therein. the Baffle Step Compensation suggestion is a great one - i'm going to look into having something like that assembled into a small box that i can run my IC's through on the way to the power amp for the Watts. and also thanks for pointing me to the stereophile review of the Watt/Puppy. on reviewing the measurements noted here, i'm actually rethinking the project a little. Of note are the following observations...
"the WATT's bass is lightweight when used without the Puppy, the rear-facing port only adding marginal reinforcement below 70Hz or so."
"The Puppy woofer can be seen actually to cover just a relatively small region in the mid–upper-bass, from 62Hz to 152Hz, to judge by the –6dB points. The minimum in the woofer output at 28Hz confirms the port tuning"
"an important effect on the sound of the WATT [when used with the Puppy] will be to reduce the stress on the latter's 6.5" woofer, allowing a higher playback level before audible strain sets in."
if i'm interpreting the analysis correctly (highly unlikely), i may have been overestimating the low end achieved by the puppy. where the puppy is concerned, seemingly it's designed to operate from 62 Hz to 152 Hz.
given this, does it seem reasonable to high pass the Watts (to relieve stress on the 6.5" woofer), and low pass the bass modules i'm considering building, higher than my original estimate of 80 Hz... perhaps as high as 100 Hz, assuming they are capable of sounding good that high? sreten mentioned letting the Watts go full range... sounds like there's a case to be made for both arrangements.
additionally, i presume that i do not need strong output down to the mid 30's to approximate the low end of the puppys, but rather the mid 50's would get me close (blue trace, figure 8... the puppy is -10 db at 50 hz). That opens up my options where drivers are concerned, and enables me to consider some of the models that yielded lower Qtc values, but correspondingly less extension.
what would be a good target range for Qtc for these bass modules? i've read 0.7 is neutral, with as low as 0.5 being acceptable when tight, controlled bass is desired. any suggestions for an appropriate Qtc value would be appreciated.
thanks again for your willingness to share your knowledge - it's REALLY appreciated.
ok, I've come up with several iterations.
My favorite so far is two TC Epic 10" per side in 20L sealed. (four drivers total)
LT F0=63.39, Q0=.7, fp=35, Qp=.71
1.2Kw per side
that would put f3 at 35Hz and f10 at 20Hz
What is your budget?
those would sound FANTASTIC! but, given the size restraints i'm working with, the only way to use a 10" is down firing (otherwise the height would need to be around 11.5", which is too tall for my needs) and i can't see how two down firing 10's would fit. the dimensions i've got to work with are 12"W x 17"D x 10"H (30 x 43 x 25 cm) - the cabinet can not exceed 10" tall, with less than that being preferred if possible.
i think i could get away with one of the following...
one front firing 8" driver
one down firing 8" driver
two down firing 8" drivers
one down firing 10" driver
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Hmm, many woofers with enough power handling in a tiny cab tend to have too weak a compliance [Cms] for down-firing apps, so I recommend concentrating on low Vas, medium Fs, Qts, high Pe, Xmax car audio woofers such as the Peerless XXLS series: Parts Express - Subwoofer Qualification Formulae For Downfiring Configurations
GM
GM
It could be a nice integration with its benefits but requires knowlegde and preferably various measurements to get this correct. The drawback is (as you say) the limited dynamic range.
It should in my opinion be possible to integrate the sub well at higher crossover frequencies (some 80-120Hz), even though the solution deviates from the original Wilson approach.
Personally I would prefer higher dynamic range, design for good capacity and carefully tune/adjust the finished system.
To achieve "perfect" integration, in-room measurements are very helpfull. For this I will recommend to use REW or other free measuring software.
Hmmm....
That Wavecor driver T71 pointed to certainly seems pretty
good, but its 3 times the price of the dayton, c'est la vie.
T71 also touches on the issue that low bass extension
is no good if its not loud enough, but peoples typical
listening levels do vary a lot, its hard to generalise.
On a budget with a small box you accept the inevitable
compromises, but if you can chuck money at it, a big
amp with a LT'd driver (or two) will go lower / louder.
Given the form factor I'd recommend two 8" on the
left and right sides in force cancelling mode, or
possibly two racetrack drivers, like the TB W8Q-1071F :
Two of those per side LT'd shouldn't be too shabby, related to the
LT I'd tend to go for a lower Q (0.5 to 0.6) as a target, its more
likely to integrate with the room well than 0.7, and reduces the
constraints of the inevitable amplifier bass boost levels.
IMO F-3dB is irrelevant, F-6dB and F-10dB matter far more IME.
Optimising for F-3dB compromises the transient response IME.
Given the WATTs are tuned to 40Hz, a high pass filter to them at
say 100Hz, presumably 2nd order L/R, will change the nature of
the beast, allowing cleaner high levels, not much experience here.
(IMO you will still need some line level BSC correction, and most
likely at modest volumes this change will be the most important.)
All I can say is simulate and post, iterate with the feedback you get,
until something that seems sensible and fit for purpose emerges.
rgds, sreten.
As an aside I don't what version of the WATT this is but I cannot
remotely see the the PUPPY being -10dB at 62 Hz, please provide
the link - I'm sure that is not what its saying, I will explain.
That Wavecor driver T71 pointed to certainly seems pretty
good, but its 3 times the price of the dayton, c'est la vie.
T71 also touches on the issue that low bass extension
is no good if its not loud enough, but peoples typical
listening levels do vary a lot, its hard to generalise.
On a budget with a small box you accept the inevitable
compromises, but if you can chuck money at it, a big
amp with a LT'd driver (or two) will go lower / louder.
Given the form factor I'd recommend two 8" on the
left and right sides in force cancelling mode, or
possibly two racetrack drivers, like the TB W8Q-1071F :
An externally hosted image should be here but it was not working when we last tested it.
Two of those per side LT'd shouldn't be too shabby, related to the
LT I'd tend to go for a lower Q (0.5 to 0.6) as a target, its more
likely to integrate with the room well than 0.7, and reduces the
constraints of the inevitable amplifier bass boost levels.
IMO F-3dB is irrelevant, F-6dB and F-10dB matter far more IME.
Optimising for F-3dB compromises the transient response IME.
Given the WATTs are tuned to 40Hz, a high pass filter to them at
say 100Hz, presumably 2nd order L/R, will change the nature of
the beast, allowing cleaner high levels, not much experience here.
(IMO you will still need some line level BSC correction, and most
likely at modest volumes this change will be the most important.)
All I can say is simulate and post, iterate with the feedback you get,
until something that seems sensible and fit for purpose emerges.
rgds, sreten.
As an aside I don't what version of the WATT this is but I cannot
remotely see the the PUPPY being -10dB at 62 Hz, please provide
the link - I'm sure that is not what its saying, I will explain.
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For srosenberg's information... I find this issue important, but I do not preach or encourage anyone to destroy their hearing
Now and then I personally find it very tempting and funny to listen to particular records or melodies at higher than avarage levels - even very loud (average above 100dB). But just like cars, you don't need those 100 or 300 bhp engine all the time - in average 10-20 is sufficient to get from A to B.
However, the fun and realism of playing loud is so amputated if the bottom octaves don't follow the higher. Subs and basses will very early enter compression and destroy the sound balance, even make it untolerable flat and painful/unjoyful, if not designed for handling the power. A well designed sub/bass system makes the foundation of a speaker system and music reproduction - but unfortunately it is also often the most expensive part compared the the $/octave cost.
That said, I also have a friend using Quad ESL that listens at some 75-80dB and never feels the need for playing any louder - that's him not me.
Point is and just as sreten says, it is hard to generalise and the needs/ambition could only be defined by yourself.
Hi,
A link was provided, I missed it. The measurements are interesting for the V3.
The WATT on its own definitely needs some BSC reinforcement below 1KHz,
Passive EQ is dirt cheap and very effective, use a simulator, Tina-Ti is free
and very user friendly IMO. IMO you do want near 6dB correction at 100Hz.
(I'd use the averaged in room response as a basis for the correction.)
The reviewer has made the mistake of referring to the PUPPYs driver output
only, rather than the summed port + driver response, that is not shown.
-6dB at 62Hz is mentioned, bur the drivers are heading towards the port null.
Fig 8 is very bizarre, being 45 degrees off axis, the review seems slapdash.
What fig 10 does indicate IMO is lots of bass around 100Hz, which is exactly
the problem the WATT has on its own, so that demos must be a no-brainer.
FWIW the impedance issues could be problematic with valve amplifiers,
personally a 2 ohm dip in the midrange IMO is just pointless poor design,
unless its there to make sure only uber amplifiers sound good with it.
rgds, sreten.
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