That's exactly what I meant. Like my EL70 at 20hz example. At the desired SPL, it's fine. So when you tout this drivers bass performance, what are you comparing it to. How does it perform.
My room is different than your room. You may have a big mode right are 50hz lifting the "performance" of this speaker up, and I may have a big null right at 50hz, making this speaker look like it can only reach 70hz. The nearfield normalizes that. The in-room response actually means nothing. You compare it to the nearfield response to see what's happening out in the room.
The additive power sweeps show the frequencies that this speaker struggles with. So if the sweeps bunch up around 70hz (between tuning and Fs) you may hypothesis that excursion is running up. If it's broad bunching, maybe power compression. Etc.
You do this: Lilmike's Mic
You don't have to do the Linkwitz mod if you're keeping the SPL down.
Perhaps in absolute terms, the driver placement you describe would be better. However, I had specific design goals and limitations with this build, one of which was the fact that the drivers needed to be high enough to clear the foot of our bed.
Consequently, if the drivers had been where you describe, the sound would be pounding directly into the foot of the bed, which would result in them sounding considerably worse from the listening position (in the bed). I cannot imagine anyone can fail to see the obvious advantage of the driver position I chose.
If I did not have this requirement, I probably would have just built Cyburg's Needle or TABAQ.
Well I've got two in each tower, one front and one top firing. They get pretty loud and I've yet to bottom them. I am running mine as surrounds but like to move them up front every once in a while just for kicks. 4 per tower if spaced close enough could sound very good with quite a surprising amount of spl.
Scott
Scott
That's what i intend to illustrate, by frequency response analysis from the listening position. I will include an SPL measurement as well.
I will test it in two rooms and nearfield, if I have time. That should give a fairly general sense as to how it "sounds", no?
I honestly do not understand what any of that means. Perhaps I am wasting my time attempting to measure anything.
Thanks!
The nearfield will tell the most. And takes no time at all if you're already measuring in the room.
Don't worry about the power compression stuff then. I can do that with mine if I cared to prove it's good. Except I don't have mine in this enclosure.
You're not wasting your time. Unless you don't care to know. If you measure and post your measurements, then you will be able to show the extension and shape of the bass.
If you care about the >200hz performance, I have an on-axis FR I can post. I keep forgetting to grab it off my home computer though. It's very flat. I don't normally check for distortion, but there is some audible in the treble. Checking for distortion is much more difficult. Requires a very controlled setup that very few people actually do.
Don't worry about the power compression stuff then. I can do that with mine if I cared to prove it's good. Except I don't have mine in this enclosure.
You're not wasting your time. Unless you don't care to know. If you measure and post your measurements, then you will be able to show the extension and shape of the bass.
If you care about the >200hz performance, I have an on-axis FR I can post. I keep forgetting to grab it off my home computer though. It's very flat. I don't normally check for distortion, but there is some audible in the treble. Checking for distortion is much more difficult. Requires a very controlled setup that very few people actually do.
I had some time after work to mess around with HOLMimpulse, and here is what I came up with.
Blue = Listening position
Burgundy = about 1ft away from the left driver
Green = on floor, about 1ft away from the port opening
SPL meter in listening position peaked at 88.9dB
As you can see, the cheap webcam mic I am using isn't great at the top end
Blue = Listening position
Burgundy = about 1ft away from the left driver
Green = on floor, about 1ft away from the port opening
SPL meter in listening position peaked at 88.9dB
As you can see, the cheap webcam mic I am using isn't great at the top end
An externally hosted image should be here but it was not working when we last tested it.
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I have no idea how accurate it is, but the graph seems to reflect my listening experience; usable bass into the mid 30Hz range from these tiny, cheap 3" drivers which have an Fs of 106Hz. To me, that says that something is right about the cabinet, but hey, I'm an amateur. Are they hi-fi? Probably not by most definitions. Are they incredibly satisfying for the intended purpose? Oh yes!
Any time I got the mic closer, the app complained about clipping. I was too impatient to reduce the gain on the mic and/or lower the volume on the amp and start over. Nevertheless, I did run a measure with the mic about an inch from the port at one point and, despite the clipping error, the graph looked pretty much the same as it does at 1 foot. I really do think I am getting that solid 40Hz right out of the port, but again this is my first measurement session, so... grain of salt and all that.
I should also mention that the normal listening level for these speakers, in our bedroom, comes nowhere near what I was pushing through them during the test. I really only drove them that hard as a demonstration. At the medium to low SPLs that they are usually pushing (maybe 80-82dB peaks), they are very smooth and coherent all the way across the spectrum, IMO. They were never designed to be "cranked", and nobody should ever build this project with that in mind.
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Yes. There are still lots about it that I don't understand, but I was able to figure out what I needed to get the job done. Thanks for the recommendation. The other app that I was eager about ended up not impressing me.
I wish I could convince someone to model this in MJK. I am very curious to see what I have done... by accident...
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Hey Cogitech,
The near field should look something like this
You can see where there is a big null in the lower range. That's where the port kicks in. If you don't get this, something is going on. I think the room is still swamping the results. You'd have to turn it down to avoid clipping. Get as close you can.
The near field should look something like this
You can see where there is a big null in the lower range. That's where the port kicks in. If you don't get this, something is going on. I think the room is still swamping the results. You'd have to turn it down to avoid clipping. Get as close you can.
If I have some more time over the holidays I will make another effort at measuring. The next few days are going to be very busy though...
Thanks for your assistance with all this. Thanks to XRK, too.
P.S. I can't believe the "buyout" deal on these speakers is still active. I built these over a year ago! Might have to buy more, "just cuz".
Thanks for your assistance with all this. Thanks to XRK, too.
P.S. I can't believe the "buyout" deal on these speakers is still active. I built these over a year ago! Might have to buy more, "just cuz".
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The best part; they sound fantastic! Not as refined as my microTowers of course, and they reach their SPL limit sooner than the microTowers, but I never expected them to compete with the mTs anyway. I also did not expect them to sound as good as they do, with as much bass as they have. I am truly amazed what can be done with a single 3" driver. I've been walking around with a stupid grin for the last couple of hours. My wife is getting annoyed.
I also bought some (4), plan to build yours and smaller 2.1 version, with a small sub. Is there a dimension on your cabinet in this thread?
gychang
...box 42" h x 4.5" w x 6.5" d (exterior dimensions) for a total interior volume of 13.3 litres, with a tuning of 52.5hz (port 1.5" dia. x 2.5" L)...
anyone built TABAQ with these drivers, wonder what the difference will be, like the idea of TABAQ not being as tall as nanoT?
gychang
Hi gychang, I have build them both the nanotowers but a dipole versión, with one firing upwards, and the Tabaq, both sound nice, But I would choose Tabaq, becouse of size and better sound.
Here you can find some graphs
http://www.diyaudio.com/forums/full-range/88787-tabaq-tl-tang-band-30.html#post2991072
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