Hello friends.
I will be using the Accuton C173N-T6-90 6.5" Midrange driver. 93.2dB.
Znom 6 ohm, Re 6.5 ohm, fs 73Hz, Qms 6.54, Qes .32, Qts .30, Mms 15.75, Cms .3 mm/N, Sd 145 cm2, Vas 8.8 ltrs.
I would like to build the midrange enclosure as to naturally rolloff the low end at around 200Hz. I can experiment, but what volume should I start at to cut the fewest cuts for my experiment boxes?. The unit has a natural rolloff at 110Hz; if that means anything. I would like to get away from using a large Cap at the low end.
Thanking you in advance
I will be using the Accuton C173N-T6-90 6.5" Midrange driver. 93.2dB.
Znom 6 ohm, Re 6.5 ohm, fs 73Hz, Qms 6.54, Qes .32, Qts .30, Mms 15.75, Cms .3 mm/N, Sd 145 cm2, Vas 8.8 ltrs.
I would like to build the midrange enclosure as to naturally rolloff the low end at around 200Hz. I can experiment, but what volume should I start at to cut the fewest cuts for my experiment boxes?. The unit has a natural rolloff at 110Hz; if that means anything. I would like to get away from using a large Cap at the low end.
Thanking you in advance
anywhere from 2-5l sealed should do. 2l gives Qtc of .7 and -3dB around 175Hz. Pushing closer to 5l brings the Qtc to around .5 and the f3 to 200Hz
Edit: reread your title, around 1l will also bring the f3 to around 200Hz but with a bump in the reponse and a high Qtc. I would go for the 5l box in preference if space allows
Edit: reread your title, around 1l will also bring the f3 to around 200Hz but with a bump in the reponse and a high Qtc. I would go for the 5l box in preference if space allows
Thank you all for your quick responses.
I am using a tubed amp, the Atma-Sphere MA1 mklll OTL.
I was going to use a series resistor for a reason; The tweeter is the Accuton C25N-6-13, 1", with 92dB. The C173N is 93.2dB. Is this a difference I should worry about?.
What would the series resistor do to my acoustic low end rolloff idea?.
My original calculation has 1.5 l?. Where would that put my f3?.
I think I need an LCR for the cone breakup at 4500Hz, will that make a difference?.
I am using a tubed amp, the Atma-Sphere MA1 mklll OTL.
I was going to use a series resistor for a reason; The tweeter is the Accuton C25N-6-13, 1", with 92dB. The C173N is 93.2dB. Is this a difference I should worry about?.
What would the series resistor do to my acoustic low end rolloff idea?.
My original calculation has 1.5 l?. Where would that put my f3?.
I think I need an LCR for the cone breakup at 4500Hz, will that make a difference?.
Cousin Billy said:
Sensitivity match is no problem...you may even need padding down the tweeter, but may depend on other things like crossover design, or actual real life sensitivity etc.
Reason is that you will cross the mid below 200hz, hence you will need to make some BSC on the mid, which means it may be down around 90db at cross point to tweeter
A different option would be if the woofer could compensate fore the BSC both below and above mids rolloff, but it may be real tricky and be the cause of phase problems
There would be good reasons to cross the mid a bit higher, maybe just above 300hz...and then use a woofer section with sensitivity higher than the mid, though it may not be easy to make such a woofer section
Another option could be 2.5 way with addition of another but different driver... a small woofer with specs making it play lower than the "mid"...may not be that easy either
I am hoping to make something similar with bigger 18"/12" pro woofers...have not tried it yet
Appology if it sounds confusing, but thats because it really isnt that easy, either way
inertial said:Is it the Atma-sphere OCL also ?
Paolo
A quick look on the Atma-Sphere website, I'm not expert of electronics,
and there is not mentioned OCL word , but I thik it is so because the double independent floating power supplies, no need of output capacitor I suppose.
They claim the output stage is "ultra-safe", I hope for you you do not have to experiments the opposite ( rare) case !
One more: one of the function of the rear volume is to absorb the rear wave; the more volume ( stuffed) the better.
Cheers,
Paolo
Again thank you all
My Atma-Sphere amps have an output impedence of 2.3 ohms.
How will this effect QTS?. What is the ideal value of QTS?. Let's assume I will need a series resistor. If you read further down, you will see because of my choice of woofers, the series resistor may be mandatory.
If I change this question to; 300Hz acoustic rolloff, that would give me a good starting point. If the rest of the components and crossover started to impact the acoustic rolloff choice, that 300Hz point would allow a simple first order x-over?.
What is the new corresponding volume for a 300Hz rolloff?.
I will be using a pair of Accuton C220-T6-220 woofers in series, 75l enclosure, 89.6dB.
Let me add one other note. My amps are rated at 135 watts into 4 ohms, 140 watts into 8 ohms, and 150 watts into 16 ohms.
My initial calculations give me a speaker impedence of 30 ohms at 45Hz, dropping to 6.0 ohms at 110Hz. Because my amps deliver more power into higher impedences, I should get strong output in the lower octaves. The output peak of the woofers is at 100Hz. A 1st order x-over will allow the mids to help keep the base output up. (woofer cone breakup is at 2500Hz).
Help
My Atma-Sphere amps have an output impedence of 2.3 ohms.
How will this effect QTS?. What is the ideal value of QTS?. Let's assume I will need a series resistor. If you read further down, you will see because of my choice of woofers, the series resistor may be mandatory.
If I change this question to; 300Hz acoustic rolloff, that would give me a good starting point. If the rest of the components and crossover started to impact the acoustic rolloff choice, that 300Hz point would allow a simple first order x-over?.
What is the new corresponding volume for a 300Hz rolloff?.
I will be using a pair of Accuton C220-T6-220 woofers in series, 75l enclosure, 89.6dB.
Let me add one other note. My amps are rated at 135 watts into 4 ohms, 140 watts into 8 ohms, and 150 watts into 16 ohms.
My initial calculations give me a speaker impedence of 30 ohms at 45Hz, dropping to 6.0 ohms at 110Hz. Because my amps deliver more power into higher impedences, I should get strong output in the lower octaves. The output peak of the woofers is at 100Hz. A 1st order x-over will allow the mids to help keep the base output up. (woofer cone breakup is at 2500Hz).
Help
Hi,
I'm afraid I'm going to P on your parade somewhat.
Take a look at :
http://www.humblehomemadehifi.com/Humble_Statement.html
http://www.clofis.nl/nl/thiel/C13-6.pdf
Your amplifiers Zout of 2.3R (assuming it is resistive) will affect
the Qts of all the drivers as will any additional attenuation.
You need to read up on baffle step compensation.
For ~ 90dB midrange to treble you need ~ 96dB in the bass into
half space which becomes ~ 90dB into full space. The mid/treble
above the baffle step is into half space, which how all drivers
are measured for sensitivity, on a very large half space baffle.
In other words to match sensitivities you need to run the bass
drivers in parallel. Also note that for two drivers in parallel
each will see an effective source resistance of 4.6R, not 2.3R.
A highpass less midrange driver will waste power below its
box resonance. The excursion of a driver rolling off in a box
is constant with power as the frequency drops, so low bass
will still modulate the midrange, genarally this is not good.
Your amplifier does not seem to deliver much "more power"
into high impedances, though due to its output impedance
it will produce more voltage, i.e. impedance variations do
cause response variations of the amplifiers output.
Unfortunately it is not as simple as you would like it to be,
with those drivers not doing it properly would be a waste.
/sreten.
http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spkrbldg/DesigningXO.htm
http://www.zaphaudio.com/
http://www.rjbaudio.com/projects.html
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://htguide.com/forum/forumdisplay.php4?f=39
http://www.humblehomemadehifi.com/
http://www.linkwitzlab.com/
http://www.geocities.com/kreskovs/John1.html
I'm afraid I'm going to P on your parade somewhat.
Take a look at :
http://www.humblehomemadehifi.com/Humble_Statement.html
http://www.clofis.nl/nl/thiel/C13-6.pdf
Your amplifiers Zout of 2.3R (assuming it is resistive) will affect
the Qts of all the drivers as will any additional attenuation.
You need to read up on baffle step compensation.
For ~ 90dB midrange to treble you need ~ 96dB in the bass into
half space which becomes ~ 90dB into full space. The mid/treble
above the baffle step is into half space, which how all drivers
are measured for sensitivity, on a very large half space baffle.
In other words to match sensitivities you need to run the bass
drivers in parallel. Also note that for two drivers in parallel
each will see an effective source resistance of 4.6R, not 2.3R.
A highpass less midrange driver will waste power below its
box resonance. The excursion of a driver rolling off in a box
is constant with power as the frequency drops, so low bass
will still modulate the midrange, genarally this is not good.
Your amplifier does not seem to deliver much "more power"
into high impedances, though due to its output impedance
it will produce more voltage, i.e. impedance variations do
cause response variations of the amplifiers output.
Unfortunately it is not as simple as you would like it to be,
with those drivers not doing it properly would be a waste.
/sreten.http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spkrbldg/DesigningXO.htm
http://www.zaphaudio.com/
http://www.rjbaudio.com/projects.html
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://htguide.com/forum/forumdisplay.php4?f=39
http://www.humblehomemadehifi.com/
http://www.linkwitzlab.com/
http://www.geocities.com/kreskovs/John1.html
sreten, you are not p-ing on my parade if it helps me build a better speaker.
I have Tony Gee's Humble Statement info, he sent it to me some months ago. My enclosure design will be very close to his. His speakers are optimally used with solid state amplification. Since my amplifiers are staying, and they are tubed output transformerless, I am commited to the path I am on. Tube friendly speakers.
Are you saying I should offset the woofers in the cabinet's?. Should i round off the top of his speakers more?.
Any advice would be helpful. I will continue to read some of your attachments.
I have Tony Gee's Humble Statement info, he sent it to me some months ago. My enclosure design will be very close to his. His speakers are optimally used with solid state amplification. Since my amplifiers are staying, and they are tubed output transformerless, I am commited to the path I am on. Tube friendly speakers.
Are you saying I should offset the woofers in the cabinet's?. Should i round off the top of his speakers more?.
Any advice would be helpful. I will continue to read some of your attachments.
Hi,
Using a lot of info from TG build and those software tools you can
model the effects of your source impedance into the design, but
that is assuming you know exactly the nature of the source
impedance, if it basically constant resistive or more complex.
I'm not saying you should offset the woofers. I am saying for ~ 90dB
midband you need to use your two woofers in parallel for near full
BSC. If you want to use them in series then you need to be clever
and design in line level passive BSC, which is also more adjustable.
http://www.musicanddesign.com/HybridDesign.html
/sreten.
Using a lot of info from TG build and those software tools you can
model the effects of your source impedance into the design, but
that is assuming you know exactly the nature of the source
impedance, if it basically constant resistive or more complex.
I'm not saying you should offset the woofers. I am saying for ~ 90dB
midband you need to use your two woofers in parallel for near full
BSC. If you want to use them in series then you need to be clever
and design in line level passive BSC, which is also more adjustable.
http://www.musicanddesign.com/HybridDesign.html
/sreten.As far vas I know Thiel woofer dont produce much bass, if any...they are what you would call exstremely tight, no matter what you do
Well, the older models may be a bit better in this respect, and there does exist a version with 11ohm, but the new one with underhung neo rolls of around 60hz, which is redicously
Now it seems you have the money, so you could consider to use multiple woofers like the new ScanSpeak Illuminator, like say 4 woofers placed 2 on top and 2 at the bottom
Well, the older models may be a bit better in this respect, and there does exist a version with 11ohm, but the new one with underhung neo rolls of around 60hz, which is redicously
Now it seems you have the money, so you could consider to use multiple woofers like the new ScanSpeak Illuminator, like say 4 woofers placed 2 on top and 2 at the bottom
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