First speaker build, seeking guidance on full range

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BJosephs

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Joined 2011
Just doing some last minute thinking: Are there any simple bracing options that I might be able to work in? I was planning on doing this bracing free for now to keep this experiment simple. I've seen the holy brace and it's just not in the scope of this first experiment - don't have the material or tools - but something simpler might be possible. Could I cut and glue in some wooden dowels?
 
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guangui

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Joined 2013
BJosephs said:
Just doing some last minute thinking: Are there any simple bracing options that I might be able to work in? I was planning on doing this bracing free for now to keep this experiment simple. I've seen the holy brace and it's just not in the scope of this first experiment - don't have the material or tools - but something simpler might be possible. Could I cut and glue in some wooden dowels?
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What Dave said, plus, if you are going to veneer, not paint, the enclosures you can use finishing nails or small diameter screws, along with glue, to hold the bracing in place. I am not an experienced woodworker, so this technique helps me a lot to keep things aligned. If painting, you can always do the same, but need to drive the nail/screw deeper into the wood, then patch the hole; more work.
 
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BJosephs

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Joined 2011
Hi guangui,

Thanks for the advice. I actually just finished the last fabrication step before glue up. Plywood was cut up by a shop for me - things look reasonable, a couple out of square cuts to deal with but nothing major - and everything is going together with biscuit joints. I built a Thiele style guitar cab a few months back with the glue/screw method and wanted to try something different. This is a two person job for sure. I just wrapped up routing out the rebate and hole for the driver. Just need to pilot the speaker screw holes and go pick up some more clamps for glue up.

Definitely glad I didn't go with the super pensils - these things are huge as it is!
 
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guangui

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Joined 2013
BJosephs said:
Hi guangui,

Thanks for the advice. I actually just finished the last fabrication step before glue up. Plywood was cut up by a shop for me - things look reasonable, a couple out of square cuts to deal with but nothing major - and everything is going together with biscuit joints. I built a Thiele style guitar cab a few months back with the glue/screw method and wanted to try something different. This is a two person job for sure. I just wrapped up routing out the rebate and hole for the driver. Just need to pilot the speaker screw holes and go pick up some more clamps for glue up.

Definitely glad I didn't go with the super pensils - these things are huge as it is!
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Glad it's working out...Upload pics of your build when you have a chance.
 
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pnix

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Joined 2014
Scottmoose said:
-Related to the above, I would suggest being a little careful of assuming a ruler-flat on-axis response is necessarily a good guide to what might be called 'practical' performance. It's very tempting to use that as the baseline, and it does have value -I doubt many would argue on that front. However, many wideband drivers have a response trend that is rising at higher frequencies. This is not because their designers are fools who lack the wisdom of us forum-dwellers who obviously think we can do a better job than they can, but because they are trying to compensate for the naturally greater directionality of cone drivers at higher frequencies. Basically, they're putting a lift in the on-axis response to give a wider useable listening axis, which is not necessarily a bad thing, as the majority of people, especially if you don't have a dedicated listening room, do not tend to listen purely on the driver's axis. As a trade-off, it's not a bad one, although it does put them at a disadvantage if you then use the on-axis response as your comparative basis vis-à-vis drivers that are intended to be ruler-flat (or as close as possible) under those conditions.
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How does a rising on-axis response give a "wider useable listening axis"? Are you referring to time-intensity trading? If yes the numbers would need to look significantly different.

With rising on-axis response one would need to listen off-axis. In such a situation small changes in listening position will result in huge variations of the direct sound. Not a desirable situation. All full range drivers I've measured so far have lower frequency response variance around the 0 deg axis. But any full range driver with a rising on-axis response will sound shrill at 0 deg. Again not a desirable situation.
Furthermore stereo works only within a small sweet spot. Better optimize everything for that area if you're serious about sound reproduction. If a speaker needs to sound spectrally OK in any location of a room better forget about wide range drivers and build a multi way box which has wider dispersion.

Full range drivers are OK for low volume near field listening or as a cheap alternative for high directivity concepts. In the latter case only drivers of about 8" make sense.
 
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Bjohannesen

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Joined 2005
coolcat.dk/bjoern/TABAQ_TL_for_TB.pdf
Hi BJosephs

Xaborus is right, start with no stuffing. Stuff upper 2/3 rd. And yes, it is the bass to focus on. It can be hard to hear dips and peaks, but the sweep as mentioned - or playing different sinus tones, will indicate uneven SPL.

Listen to the opening, sound that is not bass if unwanted sound.

I use AudioTool with a low-cost calibrated mice. Maybe not the most accurate tool, but very good for the price. And it will show you the differences in stuffing, placement of the speaker in your listening room, baffle step correction filter etc.

Hi
Bjørn
 
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BJosephs

Member
Joined 2011
Well, I finally got the drivers mounted so I just rushed and put 1 lb in each with reckless abandon. The backs are just taped on for now but I couldn't wait to hear them so see below. I'm only 20 hours into breaking them in so volumes are low and the bass is eq'd down... but so far I am very, very pleased.

e81f9beeaf778ef5efd5a1783fcab3c3.jpg
 
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BJosephs

Member
Joined 2011
With the volumes up the bass gets a bit "wonky" so I added about 25% more fluff to each, packed a bit more into the upper 2/3 as Bjohannesen suggested, and lastly sealed the back up with 14 #8 screws. Bass is tight now - maybe a little too much so, but I'm going to keep listening and make an adjustment in a few days.

One last thought: On the subject of how appropriate full range speakers (MA drivers in pensil cabs specifically) are for "heavy" music there wasn't a ton of info or testimony to make me sure I wasn't taking a bad gamble. My opinion is that if "heavy listening" is not mutually exclusive with "critical listening" then you may be pleasantly surprised with what a low power full range speaker can offer - regardless of how much riffing their may be :)


Thanks again to everyone for all the help, totally worth it.
 
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