Danny Richie
Stunt Coordinator
- Joined
- Apr 8, 2002
- Messages
- 171
Hi Guys,
Thanks for including me in the conversation over here.
First to Christopher.
You're headed in the right direction. Whether you get kits from us or Adire your $1,000. is going to go much further that it ever would purchasing a retail product, and you'll have fun building them too.
First I'll take the MTM issue on its side thing.
Everything said so far is very accurate.
An MTM on its side will cause a dip in the off axis horizontal dispersion due to a cancelling effect of the woofers being delayed in time from one to the next.
Where it occurs, how far off axis you need to be for it to occur, and how bad it occurs is dependant on several things, some have already been mentioned.
Without getting real technical, a wide center to center woofer spacing causes it to occur sooner and the dip will get deeper faster too.
A wider woofer spacing puts the cancellation point lower in frequency where the tweeter is even less likely to help.
A low crossover point helps but most tweeters cannot play low enough to solve the problem.
Our A/V-2 and the sealed box A/V-3S has a 9.5" center to center woofer spacing. This is fairly close as MTM's go.
Woofer cancellation is pretty deep at 1kHz at 50 degrees off axis.
At 40 degrees off axis it centers around 1.3kHz and is still significant.
At 30 degrees off axis it centers around 1.6kHz and is light but still there.
At 25 degrees off axis it looks good. Frequency of cancellation has shifted up to the tweeter range and is very small.
From our web site on the A/V-3S page: "On its side, as pictured above, the off axis horizontal response is good to about 25 degrees off axis. If seating forces some to be outside that range then the standard A/V-1, with the tweeter mounted above the woofer, is recommended as it has a wider horizontal coverage range."
The A/V-2 and A/V-3S gives 50 degrees of total coverage area very accurately. For most settings this is "A" Okay.
Next subject looks like woofer surface area, big verses small, blah, blah, blah.
Here Thomas is correct about needing to be able to move more air to hit higher SPL's in low frequencies. There is no substitute for displacement when hitting high SPL's in the low frequencies.
You can't just look at surface area here though. X-max capabilities, and how a driver is loaded can make a difference too. Transmission lines like the one used on the floor standing A/V-3 adds additional low frequency output that you can't get from a ported enclosure using the same drivers.
Here though is where you have examine what is important.
Small drivers have advantages over larger ones too.
Some of you may remember that our original A/V-3 used a pair of 16 ohm 6.5" woofers. Now they use a pair of 16 ohm 5.25" woofers.
There were good reasons why we switched.
By comparison the larger woofers could produce about 4db more output in the 35 to 40Hz region.
The smaller woofers excelled in midrange speed, detail, and clarity in the higher frequencies. Other advantages are a smaller enclosure that is an inch narrower which has a higher WAF.
The transmission line design, with the newer version, controlled the woofers better in the bottom end and power handling was as good as the larger woofers.
Plus, most people use a more capable and much larger sub-woofer to cover those bottom end levels up to 50hz or so, and needing a greater low end output level of the A/V-3 was just not important.
Anytime you can relieve a woofer of low frequency duty and long exertions it will be more capable of accuracy in the higher levels. It is hard to do everything all at once and low frequencies are much more demanding of a woofer.
Distortion levels also depend on output levels. A like Darren's A/V-2 or Ryan T's A/V-1's do not suffer from low frequency distortion levels as he has mentioned. Because of the tuning level of those speakers the impedance rises sharply through the low frequency ranges and they don't see as much power in some of those ranges.
Those two speakers are 10db down by 40Hz, and 20db down by 30Hz.
Certainly distortion levels will rise at the lower levels, but the output level is so far down that the distortion level is not a factor.
If your receiver can be set to remove 50Hz and down from those speakers then the distortion in the low levels goes pretty much to zero in a big hurry. Blending with a sub in that area is pretty easy too.
So we choose the smaller drivers.
Now as far as output level is concerned:
Output level is no problem for smaller drivers. It's output level at low frequencies that are a problem.
From 60Hz and up Darren's A/V-2's will hit some high SPL's with no problem. I have driven them hard with 400 watt Melos tube mono-blocks and they were scary loud. Clean and clear, but loud!
And our speakers do not have a week midrange. Our M-130 woofers are well known for having a great midrange performance. They are widely used in the DIY community and by other commercial companies for the midrange qualities.
We strive to offer accurate speakers that are very musical. If that is what you are looking for then consider our products. If you are looking for something else then they may not be for you.
Special thanks here to our customers. You guys give great feedback and I appreciate it.
Thanks for including me in the conversation over here.
First to Christopher.
You're headed in the right direction. Whether you get kits from us or Adire your $1,000. is going to go much further that it ever would purchasing a retail product, and you'll have fun building them too.
First I'll take the MTM issue on its side thing.
Everything said so far is very accurate.
An MTM on its side will cause a dip in the off axis horizontal dispersion due to a cancelling effect of the woofers being delayed in time from one to the next.
Where it occurs, how far off axis you need to be for it to occur, and how bad it occurs is dependant on several things, some have already been mentioned.
Without getting real technical, a wide center to center woofer spacing causes it to occur sooner and the dip will get deeper faster too.
A wider woofer spacing puts the cancellation point lower in frequency where the tweeter is even less likely to help.
A low crossover point helps but most tweeters cannot play low enough to solve the problem.
Our A/V-2 and the sealed box A/V-3S has a 9.5" center to center woofer spacing. This is fairly close as MTM's go.
Woofer cancellation is pretty deep at 1kHz at 50 degrees off axis.
At 40 degrees off axis it centers around 1.3kHz and is still significant.
At 30 degrees off axis it centers around 1.6kHz and is light but still there.
At 25 degrees off axis it looks good. Frequency of cancellation has shifted up to the tweeter range and is very small.
From our web site on the A/V-3S page: "On its side, as pictured above, the off axis horizontal response is good to about 25 degrees off axis. If seating forces some to be outside that range then the standard A/V-1, with the tweeter mounted above the woofer, is recommended as it has a wider horizontal coverage range."
The A/V-2 and A/V-3S gives 50 degrees of total coverage area very accurately. For most settings this is "A" Okay.
Next subject looks like woofer surface area, big verses small, blah, blah, blah.
Here Thomas is correct about needing to be able to move more air to hit higher SPL's in low frequencies. There is no substitute for displacement when hitting high SPL's in the low frequencies.
You can't just look at surface area here though. X-max capabilities, and how a driver is loaded can make a difference too. Transmission lines like the one used on the floor standing A/V-3 adds additional low frequency output that you can't get from a ported enclosure using the same drivers.
Here though is where you have examine what is important.
Small drivers have advantages over larger ones too.
Some of you may remember that our original A/V-3 used a pair of 16 ohm 6.5" woofers. Now they use a pair of 16 ohm 5.25" woofers.
There were good reasons why we switched.
By comparison the larger woofers could produce about 4db more output in the 35 to 40Hz region.
The smaller woofers excelled in midrange speed, detail, and clarity in the higher frequencies. Other advantages are a smaller enclosure that is an inch narrower which has a higher WAF.
The transmission line design, with the newer version, controlled the woofers better in the bottom end and power handling was as good as the larger woofers.
Plus, most people use a more capable and much larger sub-woofer to cover those bottom end levels up to 50hz or so, and needing a greater low end output level of the A/V-3 was just not important.
Anytime you can relieve a woofer of low frequency duty and long exertions it will be more capable of accuracy in the higher levels. It is hard to do everything all at once and low frequencies are much more demanding of a woofer.
Distortion levels also depend on output levels. A like Darren's A/V-2 or Ryan T's A/V-1's do not suffer from low frequency distortion levels as he has mentioned. Because of the tuning level of those speakers the impedance rises sharply through the low frequency ranges and they don't see as much power in some of those ranges.
Those two speakers are 10db down by 40Hz, and 20db down by 30Hz.
Certainly distortion levels will rise at the lower levels, but the output level is so far down that the distortion level is not a factor.
If your receiver can be set to remove 50Hz and down from those speakers then the distortion in the low levels goes pretty much to zero in a big hurry. Blending with a sub in that area is pretty easy too.
So we choose the smaller drivers.
Now as far as output level is concerned:
Output level is no problem for smaller drivers. It's output level at low frequencies that are a problem.
From 60Hz and up Darren's A/V-2's will hit some high SPL's with no problem. I have driven them hard with 400 watt Melos tube mono-blocks and they were scary loud. Clean and clear, but loud!
And our speakers do not have a week midrange. Our M-130 woofers are well known for having a great midrange performance. They are widely used in the DIY community and by other commercial companies for the midrange qualities.
We strive to offer accurate speakers that are very musical. If that is what you are looking for then consider our products. If you are looking for something else then they may not be for you.
Special thanks here to our customers. You guys give great feedback and I appreciate it.
