I need low end to compliment a pair of speakers I made.
How do I go about looking at Thiele-Small parameters to determine the right choice. I'm interested in a bass range from 30-70 hz approximately. I'll be driving it with this amp.
Dayton Audio DTA-2.1BT2 100W 2.1 Class D Bluetooth Amplifier with Sub Frequency Adjustment
I'd like the speaker driver/box to be as small as possible.
Could someone please advise on how to go about just using Thiele-Small parameters.
Any advise is welcome.
Regards,
d.
In the meantime, I've just come across a driver (that is very large) used for bass guitar and on sale. Even though this goes against the size constraint, could it be used i.e. Celestion BL15-300X. Here are the parameters.
Celestion BL15-300X (8) - 15 inch Bass Guitar Speaker
General Specifications
Nominal diameter 381mm/15in
Power rating 300Wrms
Nominal impedance 8Ω
Sensitivity 96dB
Magnet type Ferrite
Voice coil diameter 63.5mm/2.5in
Coil material Copper
Cone material Kevlar loaded paper
Former material Polyimide
Surround material Cloth-sealed
Frequency range 42-3500Hz
Xmax 4.25mm/0.16in
Gap depth 8mm/0.31in
Voice coil winding width 16.5mm/0.64in
Small Signal Parameters
D=0.33m/12.99in
Fs=48.1Hz
Mair=14.15g/0.499oz
Qms=2.989
Qes=1.004
Mmd=68.24g/2.41oz
Qts=0.751
Re=3.15Ω
Vas=137.69lt/4.86ft3
BI=8.83Tm
Cms=0.133mm/N
Rms=8.327kg/s
Le (at 1kHz)0.47mH
How do I go about looking at Thiele-Small parameters to determine the right choice. I'm interested in a bass range from 30-70 hz approximately. I'll be driving it with this amp.
Dayton Audio DTA-2.1BT2 100W 2.1 Class D Bluetooth Amplifier with Sub Frequency Adjustment
I'd like the speaker driver/box to be as small as possible.
Could someone please advise on how to go about just using Thiele-Small parameters.
Any advise is welcome.
Regards,
d.
In the meantime, I've just come across a driver (that is very large) used for bass guitar and on sale. Even though this goes against the size constraint, could it be used i.e. Celestion BL15-300X. Here are the parameters.
Celestion BL15-300X (8) - 15 inch Bass Guitar Speaker
General Specifications
Nominal diameter 381mm/15in
Power rating 300Wrms
Nominal impedance 8Ω
Sensitivity 96dB
Magnet type Ferrite
Voice coil diameter 63.5mm/2.5in
Coil material Copper
Cone material Kevlar loaded paper
Former material Polyimide
Surround material Cloth-sealed
Frequency range 42-3500Hz
Xmax 4.25mm/0.16in
Gap depth 8mm/0.31in
Voice coil winding width 16.5mm/0.64in
Small Signal Parameters
D=0.33m/12.99in
Fs=48.1Hz
Mair=14.15g/0.499oz
Qms=2.989
Qes=1.004
Mmd=68.24g/2.41oz
Qts=0.751
Re=3.15Ω
Vas=137.69lt/4.86ft3
BI=8.83Tm
Cms=0.133mm/N
Rms=8.327kg/s
Le (at 1kHz)0.47mH
Big question there.
Quick answer, i wouldn't use that driver.
Hmm,
Fs 48hz
Qts .75
It won't go low enough without a bunch of eq.
How big of a driver ?
How much do you want to spend ?
How small of a box ?
2ft3 ?
Do you want a sealed box or a ported (usually lower f3 but bigger box) ?
Are you making your own box ?
If you have your heart set on that driver, possibly a bandpass, might be big though.
There are online calculators tht crunch numbers for you.
We enjoy questions like this.
Quick answer, i wouldn't use that driver.
Hmm,
Fs 48hz
Qts .75
It won't go low enough without a bunch of eq.
How big of a driver ?
How much do you want to spend ?
How small of a box ?
2ft3 ?
Do you want a sealed box or a ported (usually lower f3 but bigger box) ?
Are you making your own box ?
If you have your heart set on that driver, possibly a bandpass, might be big though.
There are online calculators tht crunch numbers for you.
We enjoy questions like this.
Greets!
Fs much too high for worthwhile 30 Hz capability; Qts much too high for a small box, though nowadays could be digitally EQ'd to meet your criteria, but with a way too tiny Xmax for such an acoustically inefficient cab alignment equates to a very low output, so would probably only be suitable for a near-field/computer desktop type system or maybe tiny room attached home/apt. system where the sub is at the listening position.
Search for highest Xmax, ~21-30 Hz Fs, < ~0.42 Qts you can find in 12-15", then compute [Vd] swept volume = Sd*Xmax to find which one moves the most air.
The Vas spec ideally needs to be high for the acoustic efficiency required for only 100 W, but then 'small as possible' will be quite large.
GM
Fs much too high for worthwhile 30 Hz capability; Qts much too high for a small box, though nowadays could be digitally EQ'd to meet your criteria, but with a way too tiny Xmax for such an acoustically inefficient cab alignment equates to a very low output, so would probably only be suitable for a near-field/computer desktop type system or maybe tiny room attached home/apt. system where the sub is at the listening position.
Search for highest Xmax, ~21-30 Hz Fs, < ~0.42 Qts you can find in 12-15", then compute [Vd] swept volume = Sd*Xmax to find which one moves the most air.
The Vas spec ideally needs to be high for the acoustic efficiency required for only 100 W, but then 'small as possible' will be quite large.
GM
Thanks Norman and GM, really appreciate!
In regards to your questions:
How big of a driver ?
12" and smaller
How much do you want to spend ?
$100 at most on the driver, don't know whether that's possible
How small of a box ?
Smaller than 2 cubic feet, if possible
Do you want a sealed box or a ported (usually lower f3 but bigger box) ?
Either is fine.
Are you making your own box ?
Yes, am planning to, however am also looking at buying a sub in the used market. Any recommendations ? This is for music listening only, not movies etc. Looking for accurate distortion free sound.
In regards to your questions:
How big of a driver ?
12" and smaller
How much do you want to spend ?
$100 at most on the driver, don't know whether that's possible
How small of a box ?
Smaller than 2 cubic feet, if possible
Do you want a sealed box or a ported (usually lower f3 but bigger box) ?
Either is fine.
Are you making your own box ?
Yes, am planning to, however am also looking at buying a sub in the used market. Any recommendations ? This is for music listening only, not movies etc. Looking for accurate distortion free sound.
GM,
Thanks for the rules of thumb etc. I was wondering, given that information, how to scour the internet to find the driver in question. I found a site that somewhat caters to querying i.e. loudspeakerdatabase.com
Are there other databases that are exhaustive, or this information is not generally collated ?
I found a few drivers that potentially would work, on the site mentioned prior.
Thanks once again for the help.
Thanks for the rules of thumb etc. I was wondering, given that information, how to scour the internet to find the driver in question. I found a site that somewhat caters to querying i.e. loudspeakerdatabase.com
Are there other databases that are exhaustive, or this information is not generally collated ?
I found a few drivers that potentially would work, on the site mentioned prior.
Thanks once again for the help.
I found a used driver that is implemented in the Yamaha HS8 subwoofer. However, cannot find the T-S parameters anywhere on the web. Would this work ?
Yamaha YF170A00 8" Woofer For HS8S | Full Compass Systems
Access to this page has been denied.
Sorry, don't have any other info. on this.
Thanks in advance.
Yamaha YF170A00 8" Woofer For HS8S | Full Compass Systems
Access to this page has been denied.
Sorry, don't have any other info. on this.
Thanks in advance.
Without qts, vas, and fs, there is no way to know what it will do without testing it.
On that 8", hard to know how much eq boost then subsonic protection that is done by its subwoofer amp.
Here are some quick tips i go by.
Ported.
I usually look for qts near .4, then that driver makes for a box as big as Vas, and you tune to its fs, that is now its f3 (3db down).
You can get around this quick rule using a low qts driver with a very low fs, but that is usually a big 15, think qts .25 - .3, fs 20hz. Off the top of my head, i think f3 tuning around 30hz in a much smaller box than qts .4
Sealeds.
If you want f3 close to 30hz.......
Usually bigger drivers with qts above .4 and again low fs.
Box can get big.
In general, porteds are smller and have higher f3.
But it can be hard to tune low (30hz) in a smaller box.
And passive radiators add to the cost.
If you toss us qts, fs, and vas, we can toss back box size, f3, tuning, etc.
I have an excel file at work where i enter driver specs and it crunches the numbers.
On that 8", hard to know how much eq boost then subsonic protection that is done by its subwoofer amp.
Here are some quick tips i go by.
Ported.
I usually look for qts near .4, then that driver makes for a box as big as Vas, and you tune to its fs, that is now its f3 (3db down).
You can get around this quick rule using a low qts driver with a very low fs, but that is usually a big 15, think qts .25 - .3, fs 20hz. Off the top of my head, i think f3 tuning around 30hz in a much smaller box than qts .4
Sealeds.
If you want f3 close to 30hz.......
Usually bigger drivers with qts above .4 and again low fs.
Box can get big.
In general, porteds are smller and have higher f3.
But it can be hard to tune low (30hz) in a smaller box.
And passive radiators add to the cost.
If you toss us qts, fs, and vas, we can toss back box size, f3, tuning, etc.
I have an excel file at work where i enter driver specs and it crunches the numbers.
Last edited:
Here.
Speaker Box Enclosure Designer / Calculator
You put in qts, vas, and fs.
Then click sealed or ported.
I used to take a partsexpress catalog, do the numbers, then write them under the driver.
That way, i got an idea what a driver can do.
Speaker Box Enclosure Designer / Calculator
You put in qts, vas, and fs.
Then click sealed or ported.
I used to take a partsexpress catalog, do the numbers, then write them under the driver.
That way, i got an idea what a driver can do.
Accurate ?
People get hostile over that one.
To me the phase angle wrap at the subwoofer point is where you hear problems.
I stuffed my 15s' port (tuned 27hz).
It wasn't any faster than the ported, just an octave less bass.
I think tuning 30hz and below is fine.
Even on the books, the transient response is the same as a sealed an octave above tuning.
I'd swear there was a 12" dayton that would have ported around 2.5ft3 and 25hz tuning.
People get hostile over that one.
To me the phase angle wrap at the subwoofer point is where you hear problems.
I stuffed my 15s' port (tuned 27hz).
It wasn't any faster than the ported, just an octave less bass.
I think tuning 30hz and below is fine.
Even on the books, the transient response is the same as a sealed an octave above tuning.
I'd swear there was a 12" dayton that would have ported around 2.5ft3 and 25hz tuning.
$73 (us, not canada)
10"
Dayton
8mm xmax
Dayton Audio DCS255-4 10" Classic Subwoofer 4 Ohm
50l. (1.74ft3)
F3. 31hz
Tune 33hz
4" port. 14.6" long
10"
Dayton
8mm xmax
Dayton Audio DCS255-4 10" Classic Subwoofer 4 Ohm
50l. (1.74ft3)
F3. 31hz
Tune 33hz
4" port. 14.6" long
Thanks Norman.
I've been using an online calculator too. I'll take the tips provided and find something as the loudspeaker database allows to do queries. That would be my best bet.
Thanks for the Dayton recommendation, however, on the parts express site this is the box info:
Optimum Cabinet Size (determined using BassBox 6 Pro High Fidelity suggestion)
Does that mean that 30Hz cannot be achieved ?
I've been using an online calculator too. I'll take the tips provided and find something as the loudspeaker database allows to do queries. That would be my best bet.
Thanks for the Dayton recommendation, however, on the parts express site this is the box info:
Optimum Cabinet Size (determined using BassBox 6 Pro High Fidelity suggestion)
- Sealed Volume 0.3 ft.³
- Sealed F3-78 Hz
- Vented Volume0.75 ft.³
- Vented F3-47 Hz
Does that mean that 30Hz cannot be achieved ?
I'm looking at the following two options:
Dayton Audio RSS265HO-44 10" Reference HO DVC Subwoofer
Peerless by Tymphany XXLS-300F50AL01-04 12" Black Aluminum Cone Subwoofer 4 Ohm
I have to bust my budget though.
Dayton Audio RSS265HO-44 10" Reference HO DVC Subwoofer
Peerless by Tymphany XXLS-300F50AL01-04 12" Black Aluminum Cone Subwoofer 4 Ohm
I have to bust my budget though.
The Dayton you listed is a dual voice coil sub, and the Peerless has a lower sensitivity than the Dayton that norman suggested, I think norman has provided a better choice at half the cost.
I used typical 4th order ported equations, and .707 qtc for sealed.
You can make a ported box whatever size you want and tune wherever.
The equation i used is an old one, but gives max flat to a low f3.
You can make it bigger and tune lower, makes for higher f3 but lower f9.
Ebs, or extended bass shelf.
My buddy would use ported sbb4, best transient response (due to tuning to fs becoming system f9).
Then he adds boost, subsonic filter at tuning (+6db).
That makes for a small box, deep extension, and huge headroom, especially for a woof/sub that naturally has no low bass (qts under .35).
In a sub, i like 30hz tuning better than 40hz, more boom, less thunk.
But this stuff can be very subjective.
You can make a ported box whatever size you want and tune wherever.
The equation i used is an old one, but gives max flat to a low f3.
You can make it bigger and tune lower, makes for higher f3 but lower f9.
Ebs, or extended bass shelf.
My buddy would use ported sbb4, best transient response (due to tuning to fs becoming system f9).
Then he adds boost, subsonic filter at tuning (+6db).
That makes for a small box, deep extension, and huge headroom, especially for a woof/sub that naturally has no low bass (qts under .35).
In a sub, i like 30hz tuning better than 40hz, more boom, less thunk.
But this stuff can be very subjective.
Is this for a house or a car ?
The rs265ho (wow, many great reviews on parts express).
but, you said keep it under $100.
The Dayton is $153
Speaker Stats
fs 27.6 hz
vas 1.23 ft3
qts 0.45
I get...………….
Standard ported
vb 1.76 ft3
f3 23.55 hz
tune 24.68 hz
Sealed
VB = 0.84 Ft3
fsb = 43.36 hz
F3 = 43.37 hz
I like that driver sealed for a car, would work nicely.
I try to aim for qtc .707 with F3 near 45hz for a vehicle.
But, a ported has less excursion near tuning = less travel = less harmonic distortion, but can bottom out from frequencies below tuning.
The $150 tymphany, I get...…….
Speaker Stats
fs 22.4 hz
vas 4 ft3
qts 0.399
Standard ported
vb 3.86 ft3
f3 22.76 hz
tune 22.65 hz
and sealed qtc .707
VB = 1.87 Ft3
fsb = 39.69 hz
F3 = 39.70 hz
Notice, peerless goes a little lower (sealed), but has a bigger box.
And qts = .4, so Vb ported = Vas
Dayton has a slightly bigger coil, so less heat melting, but usually bottoming it out will kill it faster. Peerless is a single coil also.
The rs265ho (wow, many great reviews on parts express).
but, you said keep it under $100.
The Dayton is $153
Speaker Stats
fs 27.6 hz
vas 1.23 ft3
qts 0.45
I get...………….
Standard ported
vb 1.76 ft3
f3 23.55 hz
tune 24.68 hz
Sealed
VB = 0.84 Ft3
fsb = 43.36 hz
F3 = 43.37 hz
I like that driver sealed for a car, would work nicely.
I try to aim for qtc .707 with F3 near 45hz for a vehicle.
But, a ported has less excursion near tuning = less travel = less harmonic distortion, but can bottom out from frequencies below tuning.
The $150 tymphany, I get...…….
Speaker Stats
fs 22.4 hz
vas 4 ft3
qts 0.399
Standard ported
vb 3.86 ft3
f3 22.76 hz
tune 22.65 hz
and sealed qtc .707
VB = 1.87 Ft3
fsb = 39.69 hz
F3 = 39.70 hz
Notice, peerless goes a little lower (sealed), but has a bigger box.
And qts = .4, so Vb ported = Vas
Dayton has a slightly bigger coil, so less heat melting, but usually bottoming it out will kill it faster. Peerless is a single coil also.
Humm, way behind........ so my 'knee jerk' response is dual MCM 55-2421 or bust the budget a bit and use [4] sealed = 'fat' 15" [880 cm^2] + DSP.
GM
how about this, a little over budget,
higher sensitivity, bigger coil, works well in a small box,
Peerless by Tymphany SDF-250F75PR01-06 10" Paper Cone Subwoofer
higher sensitivity, bigger coil, works well in a small box,
Peerless by Tymphany SDF-250F75PR01-06 10" Paper Cone Subwoofer
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