C = 1/(2pi R Fc) = 1/(6.28 x 8ohm x 80 Hz)
= 248.8 uF
Thank you X. Mystery solved. Now I understand where GM's 248.8uF comes from. All good.
Now that you have that sorted, let me throw a qrench into it.
While at 80 Hz the impedance is 9Ω, an octave lower it is over 50. That is sans box. A sealed box will push that resonance peak higher in frequency, a box with a hole in it (unless aperiodic) will be much more complex with 2 peaks.
Put that in you calculation ans see what happens. you will see how pooely a seies cap is that close to resonance. So if you haven’t done the box yet an sperioidc box that works to depress the resonance peal making the passive XO a bit less problematic, you dpn’t need extra bass extension.
dave
While at 80 Hz the impedance is 9Ω, an octave lower it is over 50. That is sans box. A sealed box will push that resonance peak higher in frequency, a box with a hole in it (unless aperiodic) will be much more complex with 2 peaks.
Put that in you calculation ans see what happens. you will see how pooely a seies cap is that close to resonance. So if you haven’t done the box yet an sperioidc box that works to depress the resonance peal making the passive XO a bit less problematic, you dpn’t need extra bass extension.
dave
Eyeballing the chart and doing in-head math, 250uF yields SPL 88@100hz, 83@75hz, 81@56hz below which it stops filtering so 80-82 down to 40hz. Aperiodic as Dave suggests, or try sealed ~Vas/3 (double the resonance frequency to 60hz) without the cap.
Okay, so I bought four SEAS FA22 because I got them for a very nice price.
What would happen if I simply used two FA22 in the same cabinet, just wired identically from the speaker binding posts? Higher output, more bass, higher sensitivity, or is it just a bad idea?
I saw a speaker design on the Markaudio CHR-120 where two drivers were used...
What would happen if I simply used two FA22 in the same cabinet, just wired identically from the speaker binding posts? Higher output, more bass, higher sensitivity, or is it just a bad idea?
I saw a speaker design on the Markaudio CHR-120 where two drivers were used...
Here’s a couple of pics of the first two FA22 drivers in the cabinet that they came in. I’ve hooked them up to a little QUAD Vena and I very pleasantly surprised by how nice everything sounds.
The next two FA22 will arrive tomorrow. I’ll probably try to put two FA22s in each speaker and see what happens.
After that I’ll try finding a suitable bass driver to make a real WAW.
The next two FA22 will arrive tomorrow. I’ll probably try to put two FA22s in each speaker and see what happens.
After that I’ll try finding a suitable bass driver to make a real WAW.
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Oh, and the cabs are sealed and just over 1 meter tall and have an internal volume of about 66 liters.
If you do not use a HP on the FA22 the woofer XO is gonna be low. 50-60 Hz with the 66 litre enclosure.
dave
dave
Thank you for that...
A couple of questions:
- Is there a thread here where the sound characteristics of the many various fullrangers are discussed? How does the FA22 sound compared to something from SB Acoustics or Markaudio? Does that thread exist?
- And if I want to build a simple WAW using the FA22 with a super simple crossover, which a 10" or 12" woofer would you guys recommend? This would go in a new cabinet and I would prefer to have decent sensitivity and keep the internal volume under, say, 70-80 liters: Does any woofers spring to mind? I was thinking simply about the SEAS A26 and then cross it over around 500 Hz....
A couple of questions:
- Is there a thread here where the sound characteristics of the many various fullrangers are discussed? How does the FA22 sound compared to something from SB Acoustics or Markaudio? Does that thread exist?
- And if I want to build a simple WAW using the FA22 with a super simple crossover, which a 10" or 12" woofer would you guys recommend? This would go in a new cabinet and I would prefer to have decent sensitivity and keep the internal volume under, say, 70-80 liters: Does any woofers spring to mind? I was thinking simply about the SEAS A26 and then cross it over around 500 Hz....
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You will find people’s opinons thru-out many threads. I have heard lots of MA drivers, and have FA22 (fully tweaked up) so could giv emy opinions.
With the FA22 (especially if you have 2, you only need help REALLY low down. As simple as you are going to get is a plate-amp and REL style integration.
FA22 is the kind of FR you buy to get bass from the FR, not as a WAW. A smaller driver typically makes a better midTweeter.
Makes more sense to pursue an enclosure that drags more bottom out of them Scott has published a reflex and an ML-TL that will do that.
dave
With the FA22 (especially if you have 2, you only need help REALLY low down. As simple as you are going to get is a plate-amp and REL style integration.
FA22 is the kind of FR you buy to get bass from the FR, not as a WAW. A smaller driver typically makes a better midTweeter.
Makes more sense to pursue an enclosure that drags more bottom out of them Scott has published a reflex and an ML-TL that will do that.
dave
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Thank you.
Yes, I'm gonna play around with these four FA22s. Try them with two in parallel in each speaker cabinet and just use my sub for deep bass. It's basically only when I listen to electronic music that I need the sub with the FA22 right now. So maybe I can eek out a bit more bass with four drivers and a bigger cab?
I'm pretty happy with the speakers I bought. The guy who made them put in the recommended filter to tame the treble, btw.
Thank you for your time🙂
Yes, I'm gonna play around with these four FA22s. Try them with two in parallel in each speaker cabinet and just use my sub for deep bass. It's basically only when I listen to electronic music that I need the sub with the FA22 right now. So maybe I can eek out a bit more bass with four drivers and a bigger cab?
I'm pretty happy with the speakers I bought. The guy who made them put in the recommended filter to tame the treble, btw.
Thank you for your time🙂
So I've put two FA22 in a 100L cabinet and the result are mixed:
Pros can be boiled down to: much bigger and louder sound. More live-sound, which I like.
Cons: Overblown and woolly bass and lower midrange. There's also some weird stuff going on in the top end as well but I ascribe that to lobing which (I hope) I will fix when I roll off the second driver.
I've put these drivers in a closed cabinet. It's thin-walled and still undamped and unbraced.
So a couple of questions:
- How much of the bloated, woolly bass can be ascribed to the unbraced and undamped cabinet?
- Is the 100L actually too small for two FA22?
- Would adding a port or passive radiator make it easier to control the bass? (That's just me thinking that having an outlet for the pressure would help).
Thank you all🙂
Pros can be boiled down to: much bigger and louder sound. More live-sound, which I like.
Cons: Overblown and woolly bass and lower midrange. There's also some weird stuff going on in the top end as well but I ascribe that to lobing which (I hope) I will fix when I roll off the second driver.
I've put these drivers in a closed cabinet. It's thin-walled and still undamped and unbraced.
So a couple of questions:
- How much of the bloated, woolly bass can be ascribed to the unbraced and undamped cabinet?
- Is the 100L actually too small for two FA22?
- Would adding a port or passive radiator make it easier to control the bass? (That's just me thinking that having an outlet for the pressure would help).
Thank you all🙂
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Yes, the big unbraced walls will act as poorly tuned passive radiators.
A bit. Perhaps make it aperiodic? Opposite of a Vent = PR (making it a BR is very likely to make thigns worse). Aperiodic is a whole subject on its own.
dave
Thank you. I've braced and damped now and that has helped quite a bit. For the money and my skill-level this is now a nice sounding speaker. And nice to experience what wiring in parallel does.
I do think I'll eventually try to switch one of the FA22 with a helper-woofer.
Thanks again🙂
I do think I'll eventually try to switch one of the FA22 with a helper-woofer.
Thanks again🙂
I have that driver. First of all, you don't need a high pass. The speaker is a high passed when you put it in a sealed cabinet. The impedance is so high at resonance that it actually does not have much bass. The capacitor based on calculation does not work because the Zo is too high in a sealed cabinet that the voltage division actually does not take place. Means it has literally no effect unless you are doing it at 500Hz. Xmax is rather high so it is not going to run out of steam.
Subwoofers don't make good WAW woofers IMHO. The bass lacks texture and definition. Use a proper woofer. So in you case if you are running it sealed. Just let it be as it is and let the subwoofer fill in.
The FA22 sounds awesome as a mid bass though if you add in a tweeter instead (or a 3in ch full range) I had it in a TL cabinet and it had a very realistic bass and has real punch. Much better than a normal woofer...
Did you stuff the cabinet with sound absorber materials?
My 2 cents.
Oon
Subwoofers don't make good WAW woofers IMHO. The bass lacks texture and definition. Use a proper woofer. So in you case if you are running it sealed. Just let it be as it is and let the subwoofer fill in.
The FA22 sounds awesome as a mid bass though if you add in a tweeter instead (or a 3in ch full range) I had it in a TL cabinet and it had a very realistic bass and has real punch. Much better than a normal woofer...
Did you stuff the cabinet with sound absorber materials?
My 2 cents.
Oon
Subwoofers typically do not reach high enuff to achieve a good blend with the midTweeter.
dave