Hi, yet another guy seeking some advice 
I am building my ultimate 3-way speaker system (or shoud I say 2.5?)
The bass is handled by a pair of Lambda SB12 drivers in a 125 liter sealed enclosure (build from 32 mm MDF, with a double baffle and matrix ).
It will be crossed over at 150 Hz (24 dB/octave LR) by an active crossover (Marchand XM44). A lower crossover is possible.
The mid and high unit will be in a separate enclosure on top of the bass box.
For the tweeter I was able to buy a pair of Accuton C23-6 ceramic domes for a reasonable price.
Now what mid unit to use in between?? What parameters are important here? Of course there is the sensitivity of the Accuton (89.5 dB/watt). I guess the mid unit shoud be equal or lower.
But are there any other important factors.
My short list consists of the following units:
Accuton C94-8 89.1 dB/watt
Scan Speak 18W/8545 88 dB/watt
PHL 1230 93 dB/watt @ 16 ohm => 90 dB/w @ 8 ohm!!!
Now the Lambda SB12 has a rather high Mms (145 gr). Is this important?? The SS is rather heavy too with an Mms of 20 gr, the PHL is quite light Mms 12 gr, the Accuton about 15 gr.
It is rather obvious the C94-6 will go well with the C23-6, but is it a good match with the Lambda?
Of course it would be best just to try them, but Im afraid thats not an option. There is no shop around here that sells them all.
Another question. What is a sensible cross over frequency? I was thinking of around 2500 Hz, maybe with a 12 dB series filter. Any advice on this is welcome too.
By the way I like all kind of music (classic2hard rock, female vocals I listen to a lot).
Amplifier for mid/high will be a DIY Aleph5. Low end will be driven by a Crown K2 (eventually).
Well hope this wasnt to boring, any advice is welcome.
I am building my ultimate 3-way speaker system (or shoud I say 2.5?)
The bass is handled by a pair of Lambda SB12 drivers in a 125 liter sealed enclosure (build from 32 mm MDF, with a double baffle and matrix
). It will be crossed over at 150 Hz (24 dB/octave LR) by an active crossover (Marchand XM44). A lower crossover is possible.
The mid and high unit will be in a separate enclosure on top of the bass box.
For the tweeter I was able to buy a pair of Accuton C23-6 ceramic domes for a reasonable price.
Now what mid unit to use in between?? What parameters are important here? Of course there is the sensitivity of the Accuton (89.5 dB/watt). I guess the mid unit shoud be equal or lower.
But are there any other important factors.
My short list consists of the following units:
Accuton C94-8 89.1 dB/watt
Scan Speak 18W/8545 88 dB/watt
PHL 1230 93 dB/watt @ 16 ohm => 90 dB/w @ 8 ohm!!!
Now the Lambda SB12 has a rather high Mms (145 gr). Is this important?? The SS is rather heavy too with an Mms of 20 gr, the PHL is quite light Mms 12 gr, the Accuton about 15 gr.
It is rather obvious the C94-6 will go well with the C23-6, but is it a good match with the Lambda?
Of course it would be best just to try them, but Im afraid thats not an option. There is no shop around here that sells them all.
Another question. What is a sensible cross over frequency? I was thinking of around 2500 Hz, maybe with a 12 dB series filter. Any advice on this is welcome too.
By the way I like all kind of music (classic2hard rock, female vocals I listen to a lot).
Amplifier for mid/high will be a DIY Aleph5. Low end will be driven by a Crown K2 (eventually).
Well hope this wasnt to boring, any advice is welcome.
A higher Mms takes the Fs down. Also the efficiency goes down.
Look at the Cms. If this is high the Fs goes up agian and efficiency goes down again. (You need more force to move the cone)
A driver with high Mms and low Cms has higher efficiency but can sound boomy.
In this case I think it's best tu use an amp with higher DF.
Look at the Cms. If this is high the Fs goes up agian and efficiency goes down again. (You need more force to move the cone)
A driver with high Mms and low Cms has higher efficiency but can sound boomy.
In this case I think it's best tu use an amp with higher DF.
Okay, lowering the bass/mid crossover might me better. Lets say 100 Hz (if I set it to 50 Hz, the Lambda wil hardly be used I think )
The Cms of the Lambda is 0.4 mm/N, don't know if thats high or low.
The Crown amp I want to use for the sub has a DF of 3000 (10-400 Hz), so no problem there I think. Also it has lots of power ( see http://www.crownaudio.com/pdf/amps/136713.pdf). Probably a 350 watt@8 ohm K1 will be enough if I drop to 100 Hz. Fortunately the amps are very efficient (>90% or so, not a lot of heat here)
The PLH will not be a good choice I understand. So the Acouton and SS are the remaining competitors. Both can do 60 Hz in a appropriate BR housing.
A MTM setup is nice, buT I have a few problems with that:
- The efficiency will double I guess so probably exceed the 89.5 dB/w of the Accuton tweeter.
- I always see that using 2 woofers (or mids) results in low impedances ( < 4 ohm) and more irregular curves. A SE Aleph5 is not that fond on this. Impedance should remain above 5 or 6 ohm.
- costs, not that much of an issue if its good (I will use the speakers for 10 years or more).
Or do I see things wrong here??
What about the 2500Hz crossover point, does that make sense or should I aim higher?
Thanks for the answers so far,
Ronald
)The Cms of the Lambda is 0.4 mm/N, don't know if thats high or low.
The Crown amp I want to use for the sub has a DF of 3000 (10-400 Hz), so no problem there I think. Also it has lots of power ( see http://www.crownaudio.com/pdf/amps/136713.pdf). Probably a 350 watt@8 ohm K1 will be enough if I drop to 100 Hz. Fortunately the amps are very efficient (>90% or so, not a lot of heat here)
The PLH will not be a good choice I understand. So the Acouton and SS are the remaining competitors. Both can do 60 Hz in a appropriate BR housing.
A MTM setup is nice, buT I have a few problems with that:
- The efficiency will double I guess so probably exceed the 89.5 dB/w of the Accuton tweeter.
- I always see that using 2 woofers (or mids) results in low impedances ( < 4 ohm) and more irregular curves. A SE Aleph5 is not that fond on this. Impedance should remain above 5 or 6 ohm.
- costs, not that much of an issue if its good (I will use the speakers for 10 years or more).
Or do I see things wrong here??
What about the 2500Hz crossover point, does that make sense or should I aim higher?
Thanks for the answers so far,
Ronald
The 16 Ohm PHL 1230 you mentioned will go 8 Ohm if doubled. 96dB will be the midband sensitivity of the pair. If you correct -4dB for 4pi to 2pi step compensation you will get 92dB. Use one PHL 1220 8 Ohm instead. Half the pair's money, same impedance, 89dB when corrected, single point source. Fair enough?
Keep in mind that the PHL steps allover many well respected High-End brands when it comes to sound quality. Nexo, L-Acoustics, Stage Accompany etc. have reasons using PHL.
Keep in mind that the PHL steps allover many well respected High-End brands when it comes to sound quality. Nexo, L-Acoustics, Stage Accompany etc. have reasons using PHL.
You may want to consider putting the mid in a sealed box with a Q of .7. This will determine F3. Then use a 2nd order high pass module in the Marchand with with the same F3.
The combined rolloff of the enclosed mid and the high pass module will provide a fourth order high pass with an F6 equal to the aforementioned F3.
With a low pass 4th order module with F6 set to the same frequency as F6 of the high pass, you will then have a perfect LR
fourth order network.
You may also want to consider a more efficient mid as you will need to compensate for the baffle step roll-off unless the Marchand can do this for you.
The combined rolloff of the enclosed mid and the high pass module will provide a fourth order high pass with an F6 equal to the aforementioned F3.
With a low pass 4th order module with F6 set to the same frequency as F6 of the high pass, you will then have a perfect LR
fourth order network.
You may also want to consider a more efficient mid as you will need to compensate for the baffle step roll-off unless the Marchand can do this for you.
More intersring ideas.
Btw WinISD gave for a sealed box with Qtc = 0.71 for the 1220 a volume of 4.21 liter and Fb of 135.8 Hz. Maybe I did something wrong, but is seems a little high.
Will have to do some reading how to calculate baffle step roll-off
Marchand XM44 does have an option for baffle step correction. Didnt purchase that (yet)
Btw WinISD gave for a sealed box with Qtc = 0.71 for the 1220 a volume of 4.21 liter and Fb of 135.8 Hz. Maybe I did something wrong, but is seems a little high.
Will have to do some reading how to calculate baffle step roll-off
Marchand XM44 does have an option for baffle step correction. Didnt purchase that (yet)
Actually I don't like 4 ways. Most of the time you will crossing over somewhere between 300-1500. I always understood thats a rather critical area.
Using a (stereo) sub to support a 3 way system is perhaps more sensible, eg crossover freqs of 60, 250 and 3000 Hz with 12, 8, 4, 1 " units or so. Still I would end up with too much speaker, even for my taste (a bassbox of 90*47*60 cm and a 3 way system of say 60*30*40 on top of that....)
Using a (stereo) sub to support a 3 way system is perhaps more sensible, eg crossover freqs of 60, 250 and 3000 Hz with 12, 8, 4, 1 " units or so. Still I would end up with too much speaker, even for my taste (a bassbox of 90*47*60 cm and a 3 way system of say 60*30*40 on top of that....)
60,250,3000Hz is a 4 way? right? 12" 8" 4" 1"?
ok i am in agreement with you on many counts.
when i built my system in 1995 in too used a 2way+ sub route.
my subs use 2 x 12" (each) from Audio Concepts (www.audioc.com)
the 2 way is a MTM using 8546 and 9900
today there are better drivers available...besides I managed at the time to get the SS drivers at a fraction of the retail price and that was the only way i could afford the system
i am very impressed by the accuton drivers particularly the 23-6 and 94-8 that you mentioned. also PHL. so i was thinking yo could use the PHL from 60-250, the 94-8 from 250-3k, and the 23-6 from 3k up
another alternate would be a sub + 2 way using a Jordan JX125 or 150 with a Raven or Esg
ok i am in agreement with you on many counts.
when i built my system in 1995 in too used a 2way+ sub route.
my subs use 2 x 12" (each) from Audio Concepts (www.audioc.com)
the 2 way is a MTM using 8546 and 9900
today there are better drivers available...besides I managed at the time to get the SS drivers at a fraction of the retail price and that was the only way i could afford the system
i am very impressed by the accuton drivers particularly the 23-6 and 94-8 that you mentioned. also PHL. so i was thinking yo could use the PHL from 60-250, the 94-8 from 250-3k, and the 23-6 from 3k up
another alternate would be a sub + 2 way using a Jordan JX125 or 150 with a Raven or Esg
I think I will try to work out a box with a single PHL1220. Probably lower the crossover freq to the Lambdas in the future to around 100 Hz.
Salas, I understood you use the 1220 crossed over at 3000 Hz with a third order filter. Do you have some schema of that filter?? would be nice to have some starting point for the filterdesign, because I'm new to it.
Personally I think the Thiel will be able to handle a little lower crossover, especially with 18 db/octave. Maybe someting like 2700 Hz or so.
Btw Navin, ik I had a much larger room (than 43 m^2) I would opt for a 8" PHL + this 90 mm Accuton. However, I hope 3 units will be enough for me to cover 30 hz - 20 Khz.
Salas, I understood you use the 1220 crossed over at 3000 Hz with a third order filter. Do you have some schema of that filter?? would be nice to have some starting point for the filterdesign, because I'm new to it.
Personally I think the Thiel will be able to handle a little lower crossover, especially with 18 db/octave. Maybe someting like 2700 Hz or so.
Btw Navin, ik I had a much larger room (than 43 m^2) I would opt for a 8" PHL + this 90 mm Accuton. However, I hope 3 units will be enough for me to cover 30 hz - 20 Khz.
>Now what mid unit to use in between?? What parameters are important here?
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To get the optimum tonal balance, you've limited your selection to whatever Accuton recommends for its tweeter due to its diaphragm material. At the other end, you're starting with an underdamped alignment that will only get more so if driven hard enough to induce VC thermal compression, so like the others recommended, the lower/steeper you can XO it the better.
GM
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To get the optimum tonal balance, you've limited your selection to whatever Accuton recommends for its tweeter due to its diaphragm material. At the other end, you're starting with an underdamped alignment that will only get more so if driven hard enough to induce VC thermal compression, so like the others recommended, the lower/steeper you can XO it the better.
GM
what are the pro and cons of using 3 drivers with high order fitler sopes (3rd order +) v/s using 4 drivers with low order filter slopes (6 or 9 db/octave)
Accuton states on their site that their driver are all very wide range and can be used with 1st order XOs. Is this accurate? for example the 79-6 can be used from 200-4k? 1st order wow!
Accuton states on their site that their driver are all very wide range and can be used with 1st order XOs. Is this accurate? for example the 79-6 can be used from 200-4k? 1st order wow!
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