A few pages ago I discussed adding 2 12" subs to help out the bottom end. Not to use a crossover between them and the arrays and be done with it, but to see if I could use the subs to balance the left and right side separately. Right now the left side works harder at 30 Hz, while the right side makes up for a dip in the left array at ~70 Hz.
The subs would be used to level that out, while making the job of the arrays a bit more relaxed in the bottom end.
In my basket would be 2x 12"subs from Scan Speak, the 30W/4558T00 and 2 sub amps ~300 to 400 watt power (including headroom) yet to be determined.
It's not needed for music, but would help with Home Theatre and might make things more interesting if I can use them to balance the sound even more.
It's more of a challenge to see what I can do with it. While creating more headroom at lower frequencies. I'll still run the arrays full range, though with a more relaxed first octave.
The subs would be used to level that out, while making the job of the arrays a bit more relaxed in the bottom end.
In my basket would be 2x 12"subs from Scan Speak, the 30W/4558T00 and 2 sub amps ~300 to 400 watt power (including headroom) yet to be determined.
It's not needed for music, but would help with Home Theatre and might make things more interesting if I can use them to balance the sound even more.
It's more of a challenge to see what I can do with it. While creating more headroom at lower frequencies. I'll still run the arrays full range, though with a more relaxed first octave.
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The is what has been so great about this thread. You have shown us measuring is worth the hassle. But more importantly I have learned thru your example, what the measurements are actually showing us and how we can use them to optimize our systems.
This is an accomplishment in itself. The two other systems I have built: Avebury and my four way open baffle, have their favorite recordings. (Although I am reworking the open baffle and have not tried DSP with them yet, so we well see if that takes them to a new level.) With the Cheap and Cheerful Arrays, I got closer to enjoying everything, although missing that "bit more" the other systems had on those "select" recordings. Hence, part of my reasoning for redoing the cabinets. The measurements showed Avebury had a cleaner Impulse response early on in the 0 - 3ms area, which I believe is due to the better cabinet, as it is placed in the same spot in the room as the arrays. It makes sense, as the cabinets of the arrays was an absolute hack build with lots of sharp corners. We will see how much better the new cabinets measure. We will also see how well the circular shape works too.
Either way, Know, Ronald, that You are a great inspiration on this forum.
Thank you Allen, that's a kind thing to say.
I love the spirit of this thought, BYRTT! This made me smile this morning!
All I seem to do is listen lately. Can't stop smiling either! Still that headroom project is eating on the inside. What if...
This week no listening for me though, I can hear the high tones but the lower ones are blocked by a cold. How I love our climate...
Suddenly the system in my car seemed way more bright than usual! No way I'm firing up the arrays while that lasts. It would only lead to (very) bad decisions.
This week no listening for me though, I can hear the high tones but the lower ones are blocked by a cold. How I love our climate...
Suddenly the system in my car seemed way more bright than usual! No way I'm firing up the arrays while that lasts. It would only lead to (very) bad decisions.
A quick question from a complete audio novice: If the enclosure volume behind each Vifa unit was increased from 2 litres to 4 litres what measurable effect would this have on the very bottom of the frequency response?
In other words would the -3dB point be extended or would there be less frequency response boost needed for the lower end?
Thanks.
In other words would the -3dB point be extended or would there be less frequency response boost needed for the lower end?
Thanks.
You'd need a bit less power on the bottom end to reach the same numbers. Even though I say a bit less, look at the link Perceval added, these numbers rise fast.
I use a liberal amount of stuffing making my enclosure "seem" bigger than it is, confirmed with impedance measurements, but that's not going to make 2 litres turn into into 4.
Bigger would be better from a bottom end perspective, but the net gain is only marginal once you pass 2 litres. A good simulator software can show you this.
Here's an impedance plot as measured compared to the design using 52 litres (my internal volume excluding drivers)
You'll notice my peak is way lower than the simulation suggested.
Part of this is the use of a multiple driver array not being calculated correctly. It would take 250 litres in WinISD Pro to come close to my measured result:
In WinISD I just chose 25 drivers while in reality they would be wired in series/parallel.
I use a liberal amount of stuffing making my enclosure "seem" bigger than it is, confirmed with impedance measurements, but that's not going to make 2 litres turn into into 4
.Bigger would be better from a bottom end perspective, but the net gain is only marginal once you pass 2 litres. A good simulator software can show you this.
Here's an impedance plot as measured compared to the design using 52 litres (my internal volume excluding drivers)
You'll notice my peak is way lower than the simulation suggested.
Part of this is the use of a multiple driver array not being calculated correctly. It would take 250 litres in WinISD Pro to come close to my measured result:
In WinISD I just chose 25 drivers while in reality they would be wired in series/parallel.
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I found that some of the simulators do not seem to like the TS parameters of the TC9 and give some strange results. I had to go up to 400 litres for a single driver to get the Q to be anywhere near 0.8 with Jeff Bagby's woofer simulator. That is in no way to run that spreadsheet down as I have found it to be very accurate in comparison to others with bigger woofers.
The Bassboxx Pro sims I ran seem right to me so I am fairly confident in them at least from a comparative point of view. A 2L effective chamber shows a Q of 0.8 and an F3 of 139Hz which matches pretty well to your actual measurements.
This is the excursion plot to go with the graph I posted on the other thread, as you can see the yellow trace (10 litres) exceeds xmax with a lot less than 18 watts below resonance as there is very little cone control. The box is bigger and more efficient but not well controlled. 4 litres would go somewhere in between the yellow and red.
To me the Qt is too high to go any higher than 2.5L. Maybe if you were trying to use a flea powered SET amp there might be a valid reason but with a solid state amp of 100W or more I don't see the point.
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wesayso, clean your inBox, can't send you new messages... yours is full... busy man!
Again? Should be alright now
I can't believe the number of line array threads lately... keep this up and we might need our own separate forum under loudspeakers .
We don't really belong in the full range, nor in the multi way. Neh it would be a shame, because we wouldn't be as visual to the regular traffic.
Sometimes I forget to check out the Planars and Exotics forum even though there are jewels to bee seen there as well.
Lets keep it as is...
.We don't really belong in the full range, nor in the multi way. Neh it would be a shame, because we wouldn't be as visual to the regular traffic.
Sometimes I forget to check out the Planars and Exotics forum even though there are jewels to bee seen there as well.
Lets keep it as is...
Wesayso,
Your line array is set up for your room.
Would there be any acoustic problems if it was used in a room with a 9-foot ceiling or even a 10-foot ceiling?
In other words, would the number of drive units per array have to be increased from the existing 25 units to accommodate (in terms of acoustic performance) the extra height of the ceiling?
Thank you.
Your line array is set up for your room.
Would there be any acoustic problems if it was used in a room with a 9-foot ceiling or even a 10-foot ceiling?
In other words, would the number of drive units per array have to be increased from the existing 25 units to accommodate (in terms of acoustic performance) the extra height of the ceiling?
Thank you.
Not wesayso but as long as you cover at least 70% of the room height the floor to ceiling concept still holds.
You can certainly use more drivers to cover the full height which may have some benefit or may make it more difficult to get a reasonable impedance depending on the number of drivers.
Full height is also difficult unless you build it in place or have a ceiling soffit as otherwise you can't tilt it upright.
Placement, EQ, room treatment etc. are all much more important to the final outcome than the exact coverage as long as you make it over 70% with more obviously being better.
I can't believe the number of line array threads lately... keep this up and we might need our own separate forum under loudspeakers
I think the availability of flexible EQ and FIR options has made taming the issues arrays present a much more realistic proposition. Frequency dependant windowing also helps to show that the combing is more of problem for the eye than the ear
I think that your towers took the concept to a much more refined place both aesthetically and sonically. Certainly they were the main inspiration for me to try my own
Did you see my post regarding Vifa/peerless?
This is the fiberglass version the one in the IDS25:
Anybody interested in a group buy of the ultimate Vifa/Peerless/Thympany driver TG9FD10-08 .
Price around $6 but there has to be many interested as minimum number of drivers for that price is >2000 pcs.
This is the fiberglass version the one in the IDS25:
Anybody interested in a group buy of the ultimate Vifa/Peerless/Thympany driver TG9FD10-08 .
Price around $6 but there has to be many interested as minimum number of drivers for that price is >2000 pcs.
