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Thanks Kipman725. I think this will work well for my needs. Since I’m just using it for testing purposes (no measurements), I won’t even need to worry about modifying it for roll off.

I need a small source device to be able to test our powered subwoofers. A phone doesn't provide enough voltage to push our subwoofers to their limits. I have used a computer with a USB interface (Focusrite 2i2) and it can get fairly loud but I forgot my computer at home one day and couldn't test. So I'm hoping for something pretty small that I can play through or attached to a phone and has enough voltage to get the subwoofers really moving. Does anyone have some ideas on such a mini preamp with subwoofer out? Thanks. David

This will trim an 1/8” off of the top part of the circle with a handheld router. Then follow that with a pattern bit with the bearing near the router to get the bottom removed. 2 bits and 2 passes and you’ve enlarged it 1/8”. https://www.amazon.com/Amana-Tool-MR0100-Bearing-Diameter/dp/B002QB0PVK

Interestingly, my 212s are the aluminum horn versions and I like them better than the wooden horn versions. Like you said, lots of opinions.

I may be the odd man out but I actually didn’t think the high-end or low-end on the SH-50s (BeastAudio’s) was that impressive, at least from a detail and articulate standpoint. To me, the high-end on the SH-50s seemed rolled off and when we looked at the measurements, sure enough, the high-end started rolling off around 17,000 Hz. On the low-end there was plenty of midbass but I didn’t find it as detailed as I would have liked. On the flip side, I thought the soundstage and point-source of the speakers were phenomenal. But overall, I liked my JTR 212s over the SH-50s because the detail was better on the 212s. I ended up taking my 212s to Beast’s house so the listening was blind A/B back and forth. I actually started a thread on AVS trying to get Danley to produce a home-theater version of the SH-50/60 with a slightly better compression driver but after some initial talks with a Danley person in the thread, it didn’t end up going anywhere. Edit: I should also mentioned that my sealed 212s were at a severe disadvantage when comparing midbass. But up top the 212s were noticeably better to my ears.

I know. Such a small table saw. I have a CNC but that table saw is so nice!

You may want to grab body filler if you’re going to paint it. Much better than high-build primer or wood putty. Looking good though. And one key with the magnets is don’t mess up the polarity unless you’re using magnets on one side and steel discs on the other side.

The modules in the SP1-4000 to SP2-12000 to my knowledge are not made by Hypex. And since I use the SpeakerPower amps for my business, my only response due to potential liability is to get SpeakerPower’s recommendation before trying it.

The SP2-12000 is a dual mono design so the channels can not be bridged. That’s what I was told by Brian Oppegaard when I asked him one time. I’m not sure what their operating configuration is.

Good point, my testing was with sealed enclosures so ported or horns would indeed be different. However, I agree with SME to go with thicker foam as I doubt 1” will do much of anything until you get over 1,000 Hz or so. The following link goes over absorption of different products and thicknesses at different frequencies. https://www.bobgolds.com/AbsorptionCoefficients.htm

I tested with my sealed 18” and 24” subs filled with blue jean insulation. I was able to measure a small difference but was able to use a very minor DSP entry to get the non-filled sub to match the filled sub. So yes there may be a minor difference but in the scheme of things, it won’t really matter and since you yourself said you didn’t like dealing with the adhesive, I say pass.

I doubt it would make any difference. Bass waves are just too long and will go through that foam like it isn’t there. For speakers, sure but for subs, don’t think you’d be able to measure a difference with the foam.

Dang, that’s almost as big as our sealed 24 at around 10 cuft. Our standard cube version is 28”x28”x27”deep but we’ve also made an end tableversion, which gets pretty big. Pretty much 30”x30” 32” tall.

You’ve tied the sides into the top and bottom but cross-bracing has been shown to be most effective. It may not need the sides tied together but if it were me, I’d probably tie the two sides together at least near the middle.

Looks really nice for anyone but especially for a rookie builder. Great work. Only comment I have is you have really nice bracing on the left and right but what about tying the two sides together?

I think you may be referring to group delay. See if the following article addresses some of your thoughts on the matter. http://stereointegrity.com/wp-content/uploads/SIGroupDelay.pdf A subwoofer is the entire system of driver, cabinet, amplifier, and signal (processing). My 24” subs are flat to 7 Hz in most rooms and I’ve played them at shows up to 120Hz. People were pretty incredulous that a 24” sub could play that cleanly and “tightly” up to 120Hz. I haven’t really compared my subs to other subs in terms of group delay but it is one of the graphs that I look at when designing a subwoofer and setting the DSP for the driver to the enclosure.

I don’t want to frighten someone away from using one but a router can be incredibly dangerous as it can jump when the bit catches, which is why you hear people telling you to cut in the direction where it pulls into the work. When cutting a hole, the bit is touching both sides at the same time so it can pull in any direction, which is why you need to take multiple passes to get to full depth in a cut. You also need to sometimes take multiple passes even when cutting in one sided the bit. My best advice is to make sure the work piece is secured and will not move during cutting. Make sure you personally have a solid, wide base to make sure you aren’t pulled off balance. And finally, make sure you have the electrical cord pulled onto your shoulder or is otherwise out of your way. You need your full concentration on routing, anything moving or getting in your way is dangerous as it will take away your concentration, which is when accidents happen. The router is a fantastic tool but needs to be respected. Please don’t be too scared by my writings, just be careful and focused. Good luck in getting things done.

Thanks. Very cool. How thick of plywood can you cut through with the 150w laser? And how fast is it in terms of inches per minute (or mm :))?

Very cool. I usually do full size tests, hadn't thought enough about doing smaller scale. Can you share more about your machine especially laser power? And is the laser able to do those dados by simply reducing the power? How consistent is the dado depth via that method? Really cool!

You probably didn’t mean higher frequencies but just to be clear for others, unsupported enclosure walls resonate lower and may start to get into the range of the subwoofer and then we might start to hear them as bad bass harmonics. Think of it as larger drums play deeper and smaller drums play higher. With bracing, we’re actually trying to make the unbraced areas smaller, which will push the panel resonances up into the higher frequencies and out of the range of subwoofer bass. The other thing I’ll say about bracing is to purposely make them uneven. If you place a long brace dead center in a panel, you’re breaking the panel into two halves with the exact same resonant frequency and then doubling the amplitude of that resonant frequency since there are 2 halves. So work on unequal bracing with maybe 45/55 instead of 50/50. And like SME stated, plan on bracing every 6-8”. This will push the resonant frequencies of the panels to around 400-500 Hz and out of the passband of a subwoofer. Looking forward to seeing this project come to fruition.

You might be better served asking over at the DIYAudio site as many over there discuss speaker designs and speaker modifications. Now Tom Danley is a true innovator in loudspeaker design but fortunately for you the SH-100B looks to be a more simple design. But even with the speaker being of a simple design, it likely won’t be as easy as simply replacing the coax with a better coax. You’ll need to worry about sensitivity and the crossover so at a minimum I think you’ll need to redo the crossover. With that said, I really wish Danley focused on more of the home theater market with slightly more detailed top end character. I think if you were able to finish this project by utilizing a better coaxial, it should make quite a difference in the detail of that speaker. Note: I haven’t heard this speaker but I’ve heard several Danley designs and felt they had rolled off top end (measurements showed this as well) as well as missing some articulate detail, which is the basis for my improvement comments. Overall I feel Danley makes some amazing speakers that could be even better with a more detailed top end.

By the way, I didn’t mean to come off as a jerk if I did. Simply meant that those are fine subwoofers but there are some pretty special subwoofers out there that you should experience too. Sorry, I am not familiar with that particular driver but you could just build an enclosure of the same size as the original REL. To really design a different size or different type of enclosure (ported for instance), you’d need to get the Thiel-Small parameters for that driver.

JTR and Seaton are over in Chicago, you may want to see if you can experience their subwoofer designs. REL and SVS make fine subs and products, both good companies but they don’t quite have the firepower many strive for on this site. You will also find there are many very knowledgeable people on this site that develop their own high-powered subwoofer designs that are extremely capable and great-sounding. And in my opinion and many others on this site, lots of bass means nothing if it doesn’t sound detailed and articulate. I hope you stick around and share your knowledge.

My commercial subs are just under 9 cf with 4,000w continuous and like I said, flat to 7 Hz with a Linkwitz Transform and room gain. So 10-12cf should give you plenty of low-end output but not as much above 40 as if you went ported but the 40+ Hz would really only be usable in venues as they’d be too loud for a home theater in my opinion. So the sealed 10-12 cf is straight forward and a proven performer while not being TOO big.

Then get cracking. Lol!