UMAX 15" Sub Build

[JonMarsh]

This isn't a design project, more of a project build report in progress-

Putting together a bigger sub for GF's HT setup- had some issues using a 10" UMAX sub in a standard PE sub cabinet (interference with brace, I think) and this is to address this, plus put something together with a cherry veneer that may at least resemble if not exactly match the equipment cabinet I talked her into buying from Magnolia HiF... you may see a pattern here, in that I am digging myself a deeper hole all the time. Hmmm.l


While looking at knock down cabinets for another project, I came across the one PE offers specifically for the UMAX 15" sub. Seemed like a pretty good deal, if the build design and quality were similar to the smaller ones I'd already been experimenting with, so I decided to go that direction, with some tweaks.



Basic assembly is straight forward, though of course, aided and abetted if you have an assortment of clamps. More clamps is always a good thing...




I put together a base made of a few layers of MDF, and of course, epoxy coated the whole cabinet with a couple of layers in preparation for the veneering.






Sanding it smooth is a bit of a time consuming process- the epoxy coat is both for the PSA backed veneer to adhere to, and is a good surface for the paint for the front panel and base.


The weather was nice and warm outside yesterday, though raw cherry shouldn't be in the sun very long, so I finished those steps after moving into the shade.




I could tell I was on a lucky streak yesterday because I even found my veneering scraping tool, and quickly, though I was prepared to make a home made one from an oak board.









The planned finishing process is to start next Saturday, doing the final sanding, then a coat or two of de-waxed shellac, a very light finish sanding, then wipe on poly. Until then, it's sitting in darkness, to hopefully prevent any uneven darkening of the cherry. I hear that's kind of touchy, and this is my first project attempting anything with cherry. The target piece of furniture is fairly light, so I aim to keep this one that way.

More reporting to come, including acoustical tests. This may get used with a Hypex sub amp I have, or it just may be driven with an Aragon Palladium mono block. Depends on whether the Hypex has the guts or not- it's got a nice EQ section, but that may not be needed in room. We'll have to see...

[Steve Manning]

The planned finishing process is to start next Saturday, doing the final sanding, then a coat or two of de-waxed shellac, a very light finish sanding, then wipe on poly. Until then, it's sitting in darkness, to hopefully prevent any uneven darkening of the cherry. I hear that's kind of touchy, and this is my first project attempting anything with cherry. The target piece of furniture is fairly light, so I aim to keep this one that way.

Looking good Jon ......... Depending on how light the target piece is, you might want to consider this stuff https://generalfinishes.com/retail-p...t#.VTUUV5Nrnng I used it on my remote table that I did a little while back that's solid cherry, there's some pic's in the woodworking advise thread. It does not add the yellowish tint that the shellac and oil type poly will to the wood. Also being water based it's great to use.

[JonMarsh]

Thanks for the recommendation- I'll check it out!

[jim1961]

Once your finished and you get to the measurement phase, id be curious what kind of EQ you employ to make the response flat.

[Hank]

+1 General Finishes - been around forever - good products

[JonMarsh]

Once your finished and you get to the measurement phase, id be curious what kind of EQ you employ to make the response flat.

That may be a little tricky- going for near field quasi-anechoic flatness is easy- the Hypex unit has a variable frequency/variable gain LF boost- including none at all. How that translates into the room, and it's acoustics, might be another matter. The UMAX drivers seem to model well in sealed or IB setups, so at least I don't have to worry about LF protection for below the port tuning.

[jim1961]

That may be a little tricky- going for near field quasi-anechoic flatness is easy- the Hypex unit has a variable frequency/variable gain LF boost- including none at all. How that translates into the room, and it's acoustics, might be another matter. The UMAX drivers seem to model well in sealed or IB setups, so at least I don't have to worry about LF protection for below the port tuning.

How the speaker measures in a near field quasi-anechoic manner seems to me secondary (almost irrelevant) compared to how it measures at your listening position. That is, after all, where you will hear it :W

[JonMarsh]

Yeah, but if the box itself doesn't do right (say, a mis-aligned ported setup) then it's not likely to be right anywhere else. I'm in favor of working on the setup and positioning; more so than EQ tricks for a specific listening position (that's my inner curmudgeon talking, of course), because if you pick the wrong listening position based on room modalities, then it would be pretty messed up for other listening positions. Obviously, all room dependent. But because the family room is quite large, and opens in to the dining room and kitchen, there aren't many issues with early reflections and just putting a sub at the boundaries works pretty well...

[jim1961]

Yeah, but if the box itself doesn't do right (say, a mis-aligned ported setup) then it's not likely to be right anywhere else. I'm in favor of working on the setup and positioning; more so than EQ tricks for a specific listening position (that's my inner curmudgeon talking, of course), because if you pick the wrong listening position based on room modalities, then it would be pretty messed up for other listening positions. Obviously, all room dependent. But because the family room is quite large, and opens in to the dining room and kitchen, there aren't many issues with early reflections and just putting a sub at the boundaries works pretty well...

You could also say, to some extent, that the proper tuning depends on its room placement. Meaning optimum tuning for one place in the room may not be the same as another. My dual 10 sub I measured in the front of my room and the back recently. The frequency responses were way different, and required: 1) a level change, 2) phase change, 3) different XO point to measure the flattest and decay properly. I also had different Group Delay issues.

Not saying the speaker shouldn't be in its design parameters and tested and measured in a near field. It should.

[JonMarsh]

Life is complicated, ain't it? :W

[JonMarsh]

Did the final sand before finish, and put two coats of the General Finishes Poly on with my Fuji Mighty Mite 4 sprayer- that combination is sweet and easy to work with. This poly sets up pretty hard in an hour and a half in warm weather, later this AM after it's warmed up I'll do a light sand and hope to do three more coats and sanding today. The water based GF poly cleans up easy, and so far the finish itself looks like it will work out fine.

Film at 11... if I have time after dinner with daughter and fiancé at a local Greek restaurant named after the island they're visiting to get married- Santorini.

Image not available

Some folks aren't charmed that I suggested this idea to them in lieu of a conventional wedding and reception, but I think this is going to work out well, as it will be a great experience for the kids, going to Europe for the first time - spending some time in Athens and London, too.

[Steve Manning]

Did the final sand before finish, and put two coats of the General Finishes Poly on with my Fuji Mighty Mite 4 sprayer- that combination is sweet and easy to work with. This poly sets up pretty hard in an hour and a half in warm weather, later this AM after it's warmed up I'll do a light sand and hope to do three more coats and sanding today. The water based GF poly cleans up easy, and so far the finish itself looks like it will work out fine.

Glad your liking the water based poly Jon ...... I thought you might like it for the reasons you've listed. You can just about get your finish done in a day with that stuff.:T

[JonMarsh]

Glad your liking the water based poly Jon ...... I thought you might like it for the reasons you've listed. You can just about get your finish done in a day with that stuff.:T

Yeah, originally I was just planning on starting on the actual application today, but as it's cool in the AM, I figured get a start mid afternoon yesterday.

I did the 400 grit sand after the first two coats and put a 3rd on- feeling and looking very good at this point, and just put a 4th coat on for now. No reason this part shouldn't be finished this afternoon; then I'll let it sit up, and mask and shoot the front panel and base. Frankly, I'm beginning to think I should have done the Ardents with this stuff.

Live and learn, thanks for the nudge, Steve.

[Steve Manning]

Yeah, originally I was just planning on starting on the actual application today, but as it's cool in the AM, I figured get a start mid afternoon yesterday.

I did the 400 grit sand after the first two coats and put a 3rd on- feeling and looking very good at this point, and just put a 4th coat on for now. No reason this part shouldn't be finished this afternoon; then I'll let it sit up, and mask and shoot the front panel and base. Frankly, I'm beginning to think I should have done the Ardents with this stuff.

Live and learn, thanks for the nudge, Steve.

You're most certainly welcome ........ as one added note .... when I did my remote table, I did 4 coats and hit the last coat when it was dry with a 2000 grit just to knock any little nibs down (very little pressure) and it turned out very smooth.

[JonMarsh]

You're most certainly welcome ........ as one added note .... when I did my remote table, I did 4 coats and hit the last coat when it was dry with a 2000 grit just to knock any little nibs down (very little pressure) and it turned out very smooth.

That's similar to my game plan for this- the way this has worked out:

• A sand with 220 and 400
• Two coats to fill the pores and build up a bit
• A 2nd sand with 400- the surface felt surprisingly rough before this, but just one pass knocked this down well
• 1st of three planned follow up coats- and it's very smooth and nice looking at this point, though not what I'd call "deep"- nice enough to draw positive comments from GF when she was on her way out to the garden
• Just finished another coat, which took very little time to appear dry to the touch- (based on touching the front panel which will be black when finished)
• One more coat, then possibly a 1000 and 2000 grit wet sand to finish the surface,
• Followed up last by minwax paste wax- probably unnecessary, but when I'm doing something different for the first time, I tend to get a bit OCD just to cover my bases.

Unless I get some kind of unexpected surprise, I'll certainly be using this stuff a lot in the future...

[Steve Manning]

That's similar to my game plan for this- the way this has worked out:

• A sand with 220 and 400
• Two coats to fill the pores and build up a bit
• A 2nd sand with 400- the surface felt surprisingly rough before this, but just one pass knocked this down well
• 1st of three planned follow up coats- and it's very smooth and nice looking at this point, though not what I'd call "deep"- nice enough to draw positive comments from GF when she was on her way out to the garden
• Just finished another coat, which took very little time to appear dry to the touch- (based on touching the front panel which will be black when finished)
• One more coat, then possibly a 1000 and 2000 grit wet sand to finish the surface,
• Followed up last by minwax paste wax- probably unnecessary, but when I'm doing something different for the first time, I tend to get a bit OCD just to cover my bases.

Unless I get some kind of unexpected surprise, I'll certainly be using this stuff a lot in the future...

I want to say that General Finishes recommends not using wax on this stuff, I'll have to check to make sure as to the why, I think it's due to yellowing which is one of the reasons to go with this finish to begin with.

[---k---]

Hurry up and get to the listening impressions and measurements.

We moved last month. I now have an unfinished basement to do whatever I want with. I already got rid of my ported sub box and am seriously thinking about getting rid of my pair of Sound Splinter 15's and picking up 4 of the Utilmax 15"s to do an IB or something. Not sure. But, I'm anxious to hear what you think of the driver. I got little more excited when you mentioned the Utilmax for an IB a while back.

[JonMarsh]

I want to say that General Finishes recommends not using wax on this stuff, I'll have to check to make sure as to the why, I think it's due to yellowing which is one of the reasons to go with this finish to begin with.

That seems reasonable, I guess I just like the idea of having something else on the surface to take the hit in case of a spill or something. The box looks fine, but I'm still thinking about another coat or two... you know, if some is good, more is better, and too much is just enough.

However, I'm with K on this, too- brought over a connector plate and some connectors and wires today so I can get this wired up- hopefully next weekend- still have to paint the front and base.

[dar47]

K, Unfinished basement! I would not go back to boxes. IB all the way baby.:B

[5th element]

K, Unfinished basement! I would not go back to boxes. IB all the way baby.:B

It depends what your expectations and requirements are. IB is the way to go if you want to get extension significantly below 20Hz, but if you're a part of the crowd that doesn't really think that that matters then going ported or PR would be the way to go. If you've got the space a properly designed ported/PR box will give you a lot more output down to ~20Hz than IB will for the same number of drivers.

IB is essentially a gigantic sealed box, so the drivers don't unload like they do in a ported cabinet, allowing you to get decent output below resonance, but beyond that that's all it really offers. IB also doesn't address room modes in any way whatsoever, which are the biggest evil when one is interested in getting quality bass in a home environment. 4 UM15 subs placed properly within the room and integrated correctly with a DSP would be a much better idea in my opinion.

[dar47]

Some good points, Matt

If 4 15's in boxes can be placed without issue where you want in the space you would have a capable system, this is especially true if your front speakers lack any real low capability and you need output to 80hrtz. For music i agree this works great. It does take floor space though.

On the IB side 2 or 4 18's in 2 manifolds ideally placed provided a comparable price performance with way more clean output especially for movies (scary when the house shakes) and I have a high pass at 20Hrtz on mine. With my Ardents and I assume K's Kon's low output is not an issue from the towers so an IB with maybe 1 small fill in box would work pretty good. Maybe just me I like the sealed sound and don't miss the ported box.

[---k---]

Matt,
Good comments and I generally agree with you. I probably should start another thread, but am not quite there yet.

I like that sub-20 hz effect. It's fun. I've heard CJD's IB. What I remember was how the bass seemed to just show up and disappear as needed.

I'm coming from a place of a dual 15 sub ported to 15.5 hz. That thing had monster power to shake a room. It was built specifically to fit one corner of one room. I got rid of it because it was just too big and heavy to carry down a full flight of stairs. It was bad enough carrying it up 5 stairs from our partial basement to the curb, and that was with the drivers removed. But, I'm never building another box that big again! If I build any more big subs, they will be sonotubes!

I'm waffling with what I want to build. I've thought about just building a new pair of ported subs. I've also seriously complemented 4 sealed 15" with one in each corner and a mini-dsp. I still have a pair of sealed boxes for my 15's and may play with them. I've even contemplated building a couple TubaHT horn subs, like I built my brother a few years back. But, I would love to get away from boxes cluttering up the room, and likely only three corners will be available because of the stairs.

I think I need to decide what I'm doing with the front stage first. I was originally thinking about going all out and building a front wall out with the IB in it, 3-identical in-wall speakers, an acoustically transparent screen, projector, and two IB manifolds below the screen at the wall 1/3 points. But, after starting to look at projectors and screens, I'm not so sure. Those screens are expensive! I also don't think I want an absolute dark bunker that works only for movies. Maybe the problem is I'm looking at AVSforums, and none of those guys do anything in moderation. There are good 70" LCDs for less than $2k now. While not as big as a projector/screen, probably big enough and a lot more versatile.

I would love to do all new speakers, but I got so much invested in the Khans and no where to put them that I may reuse them or ask CJD to do new in-wall crossovers.

Ugh, so many decisions. And a pair of bathrooms that need redone. And....

[JonMarsh]

Life is complicated, in all it's permutations... but it sure beats the alternative!

For me, I've gotten addicted to IB or sealed, because of the really tight transient response, and lack of overhang on step inputs if done properly. I'm not in any situation where I can do an IB, so its sealed boxes, though I am playing with the PR thing for HT. But don't think I'd use it for music.

[JonMarsh]

OK, this time I'm going off topic in my own thread, instead of hi-jacking Ben's again... though it's less off topic for his.


I'm seeing a number of reviews for the NAD M17 processor and M27 multi-channel amplifier for HT, and after my experience with the M22, these will get more than a small amount of consideration (funny that the plate amp I have for this build is a 400W Hypex design...

Anyway, this conclusion to the review on "Secretes of Home Theater and High Fidelity" is pretty typical:

http://www.hometheaterhifi.com/proce...es-review.html

• Super-refined sound that’s never harsh or edgy
• Full support for common audio codecs
• Fantastic remote
• Beautiful modern design

Dislikes

• No AirPlay or network streaming features though a Bluesound upgrade is in the works

As you can see, there isn’t really anything to dislike about the M17 & M27. Considering the technology and quality, the price doesn’t seem out of line when compared to other high-end components. That being said, I still look forward to the day when audio this good comes in a less-expensive form.

You’ll notice I haven’t said much about Class D vs Class AB. Many writers talk about the character and nuances of Class D and how they differ from the AB topology that’s so common in receivers and power amps. The fact is, once I started listening to the Masters’ Series, I forgot about all that.

It’s really difficult to say that any particular surround separates are better or worse than another. There are so few choices available that no manufacturer is going to put out a bad product. Differences in usability certainly exist but as far as sound quality goes, it comes down to what kind of character you want. My regular setup is an Integra 80.1 processor and Emotiva XPA amplifiers. They are clean, loud, and detailed. They remind me of a well-oiled machine that cranks out sound without protest.

The NAD combo is more like an experienced craftsman who personally and painstakingly labors over every note of music before gently releasing it to the speakers. It’s not to say that the M17/M27 combo is polite. If you want loud, you can split your eardrums without difficulty. And the M27’s heat level will barely rise above room temperature while doing it. It’s just that there’s a refinement, sweetness, and accuracy present that I haven’t heard in other Class D products.

In the simplest language, the combo sounds amazing no matter what the volume level. There’s no sweet spot; it’s just sweet no matter what. If you’re looking for high-end theater separates, you’d do well to audition the M17 Processor and M27 Amplifier. I greatly enjoyed my time with them and give them my highest recommendation.

Oh, and there is progress on the sub finishing; another fine sand on the top and another coat on already, a couple more to go today, and we should be through with the General Finishes poly. This stuff is the real deal, in my opinion- like all good finishes, it's a little time consuming, if you're OCD about cleaning the equipment after each spraying, and giving it a full 1-1/2 to two hours between coats. But, it's a great looking and feeling finish.

[Steve Manning]

Oh, and there is progress on the sub finishing; another fine sand on the top and another coat on already, a couple more to go today, and we should be through with the General Finishes poly. This stuff is the real deal, in my opinion- like all good finishes, it's a little time consuming, if you're OCD about cleaning the equipment after each spraying, and giving it a full 1-1/2 to two hours between coats. But, it's a great looking and feeling finish.

Hey Jon, I have found that you don't need to clean in between coats, just at the end of the day. Before I shoot a second coat I make sure that if there is any dried poly at the tip to clean that off and give the sprayer a good swirl to make sure the poly is mixed and your ready to go. At the end of the day if you plan on shooting the next day, fill and spray two fills of hot water though the gun and your good to go. I don't know if you follow Marc Spagnuolo of the Wood Whiperer, but he has a good video on using this stuff. http://www.thewoodwhisperer.com/vide...ode=posts&ap=1. Apparently he spent some time in a finishing shop so he seems to know his way around finishing. His site is a good source of wood working information in general.

[JonMarsh]

Hey Jon, I have found that you don't need to clean in between coats, just at the end of the day. Before I shoot a second coat I make sure that if there is any dried poly at the tip to clean that off and give the sprayer a good swirl to make sure the poly is mixed and your ready to go. At the end of the day if you plan on shooting the next day, fill and spray two fills of hot water though the gun and your good to go. I don't know if you follow Marc Spagnuolo of the Wood Whiperer, but he has a good video on using this stuff. http://www.thewoodwhisperer.com/vide...ode=posts&ap=1. Apparently he spent some time in a finishing shop so he seems to know his way around finishing. His site is a good source of wood working information in general.

That's a great link- thanks. I was thinking about that today, cleaning the gun completely each time, but as you know I don't know what I don't know, and I figure better safe than sorry. I'll keep that in mind in the future, especially when I just shooting a couple or three coats.

I do love my Fuji Mighty Mite IV, though, so I figure a little extra work taking care of it is not really a big deal.



I believe at this point I'm done spraying this cabinet- it's looking quite nice to me, I did a 400 grit on the top first today, which was feeling just a little rough after the last three coats, and just finished a second set of three.




As I'm wont to say, I'm really just a wires and sparks guy trying to play a woodworker on TV, and not really doing a good job of it!



But GF is quite happy with how this looks, and so am I - so I can put a checkmark on the calendar for the various things done, including this.

I wish I wasn't traveling on business next week and needing to attend to work stuff for the trip tomorrow- I could probably have this finished this weekend otherwise.

[5th element]

I'd be quite happy with that too. The finish looks like it will be very forgiving over time too.

[Steve Manning]

Looks very nice Jon:T

Your right 5th on the finish being rather forgiving ..... my understanding is if it's gets scratched all it takes is a light sand and spray on another coat or two of finish and it's all better. As a matter of fact I stuck my fat fingers on a recent project that was not completely dry (on the last coat no less) and the process does indeed work.

[JonMarsh]

Final finishing and assembly

This space reserved for final finishing and final assembly pictures not on this computer- very routine stuff, just time consuming. As always, coating MDF with epoxy and sanding it smooth makes a great base finish for any follow on work- should be mandatory, IMO.

After getting the basic wood finish taken care of, next step was masking and spraying the front baffle and base- this was just high end rattle can work, I didn't want to run black paint through the HVLP sprayer for such a non-critical task.




The finished results met my modest expectations for appearance - I wasn't looking for a piano black style finish, just something durable a little beyond flat black... W



The Dayton Audio subwoofer feet kit (as used on their own finished sub cabinets) works quite well, and is something I use on all floor standing speakers these days, where and when I can't get away with a spike setup (such as GF's hardwood floors!).




As always lately, I have my faithful quality audit companion, making sure I do a good job writing up these projects, cleaning up the photographs, and taking a break to give her some attention...






Six inch thick fiberglass was cut into pieces to do a wrap around quarter wedge in each corner between the braces, then a roughly foot square piece to go over the center brace area where the four braces meet. The cabinet is sitting on a carpeted small furniture dolly, the sort you can usually buy at hardware stores, which makes it much easier to move around, as it is getting rather heavy.



Push a few bits out of the way and slide it into a possibly temporary position (possibly not!) - the Hypex plate amp will need a small enclosure, probably make something with scraps of LBL and MDF.



And for those who are interested, the near field response of the UMAX 15 in this PE recommended enclosure kit:

RAW driver response, full range:




Response with 120 Hz crossover in Hypex DS4.0 with a dab of low end EQ:



Both measured with the cabinet on it's back, driver pointed up, and mic at about 18". (always measure "near field" at driver diameter away for integration)

Subjectively, when the driver is in the lower frequency part of the sine chirp sweep, it definitely shakes the walls and rattles the pictures and stuff... it gets the job done, no muss, no fuss. Same goes for the Hypex DS 4.0 plate amp, which is 400W at 4 ohms. OTOH, integration with music and bass in the higher part of the range seems just fine- note the extended response to 500 Hz, which means the crossover doesn't get significantly modified by subwoofer problems just above the crossover point- so the phase response should be good in the crossover region. Pretty good for a 15" driver.



Now, here's a wacked out idea- build one of these with the 15 or 18 with a DS 4.0 driving it or them, and use the high level inputs, with outputs from the stereo mains (say, Ardents or Isiris or Modula MT or whatever...) and just turn the crossover frequency way down and use it just to fill in the bottom octave. After I rebuild the 10" one I may play around with the concept, possibly just for some computer monitors, but who knows... might work pretty wicked with some of the low frequency module designs I'm playing with for the line arrays...

Also, if I was doing this for myself, I'd probably go with the Denovo 4 cu ft enclosure, which would give a somewhat lower FB, but considerations for GF's system, and the height of the 3 cu ft enclosure, which matched the component cabinet, that seems to have been the right choice.

[JonMarsh]

Post mortem on the original 10" UMAX...

OK, the $64 dollar question is what went wrong with the original 10" UMAX build? I heard a rattling kind of sound within a week or two of first setting it up for GF, and it's been that way for over a year, though it makes the LF output expected, too.

I've got a couple more pictures, but basically it seems to be a combination of the glue on the front surround detaching several places, and in spite of dual spider assemblies, the voice coil rubbing on the pole piece, though with its very heavy duty construction, continuing to work as the rubbing was only on the inside of part of the VC former.

It's hard to get an auto focus setup to focus on the inside of the former, as opposed to somewhere outside, but this is clear enough to highlight the issue.

I would call this a driver fault, and I should have investigated it immediately after noticing the problem- but being so busy, and as it was making woofs and GF thought it sounded OK, didn't hear what I did bad, it just got put off.

I don't know if this was a problem confined to single driver or just that family of drivers; the 15" is working fine in the new cabinet. Given all the work put into the small sub, I'm torn between ditching the cabinet, and actually rebuilding it with another UMAX 10' and another Hypex DS4. The amp seems to work quite well, and of course, it's my favorite class D brand.

If a second 10" fails, then we have a syndrome to be concerned about.

Any one else had any issues with the UMAX drivers?

[JonMarsh]

Not an uncommon issue...

On the UMAX 10" reviews... there is a frequent story on this driver. I will take a look at the reviews for the other models. Sounds a like likes they have QC issues and my experience was by no means unique...

I feel your pain. I had two drivers with mechanical noise. I returned one (spider rattle... QC issue with gluing) and just haven't had the time to return the other one yet. I replaced the UM10-22 on my application with a Sundown sa8-v2 and was blown away at the difference. Granted, the Ultimax was in the recommended sealed enclosure, the sa8v2 in the recommended ported, but I was surprised the Ultimax could even be used in a sealed enclosure. It was SO no matter how much power it was fed. I am willing to bet these subs are really supposed to be for ported. After hearing the sa8v2 in the slot port box, I wondered why I ever went sealed! Nobody believes an 8 can do what is being done in a Miata...

The mechanical rattle is internal on the 2nd driver, and is evident during excursion below xmax. At the time I had experienced the issue, I had to box up several projects as I had to raise children. Still do.. but I'm wanting to get back to my hobbies.

Btw... I saw what appeared to be potential misalignment issues with the two drivers I had experience with. The rubber surround and bumper seem offset, and that can make a voice coil slap inside the gap. My first Ultimax had slight misalignment, but the 2nd one is worse. It looks as if the bumpers were glued on a little sloppy. I don't care much for looks, but I have been spoiled by the QC of other Dayton products, so I can say this particular sub seems to have been made by an entirely different club.

Response from Parts Express:
Mike V · Product Management · a year ago
Austin, I apologize for the issue that you are having with the Ultimax 10" subwoofer. I, myself, have two of these in my car and have had nothing but tremendous performance from them.

These subwoofers have an industry-leading 5-year warranty for defects in material and workmanship. Please contact our technical support staff for a return authorization to get a replacement.

I am quite certain you will find the replacement will be more than satisfactory!

♂
austin123a · 6 months ago
I received my replacement a few months ago a finally got around to installing it. Got the same noise. I used the old box first, then a new smaller box. Even free-air this speaker makes an obvious mechanical noise. I ran it for a few days at medium volumes to see if breaking in the suspension would help, but it didn't. I'm beginning to see why the price on this sub was dropped from $160. I don't see the point of returning it for another $30 shipment cost...I'm already into a useless sub for $200.

Caveat Emptor... I've already promised GF that if the UMAX 15 develops a problem, it will be replaced with a different brand of driver. However, I'm not very worried, as checking the reviews, there are no reported problems, and all users of the UMAX 15" seem to be pretty satisfied.

BTW, the 10" UMAX is out of stock, new stock not expected until July 14. Maybe this time it will be sorted out properly.

[Face]

John, do you have any measurements of the 10 that you could share? I'm curious about how high it could be used. Thanks.

[JonMarsh]

I do have some- I'll have to go look them up- will post later, probably by this evening.

Found it quicker than I expected...

Similar actually to the 15".



Probably usable to about 300-350. With the copper pole cap, distortion should be kept at bay in that range. efficiency is quite low, though- something to keep in mind unless you're purely active.

An alternative combo would be SW223BD02, with the scanspeak Pr, stock weight, in a 1.25 cu ft enclosure (Driver out front, PR out back). It models very well, down to about 23 Hz, goes up high quite clean, (based on the driver alone), and I should be testing a built example pretty soon. more bucks, of course...

[Face]

Thank you again Jon.

[Steve Manning]

Jon, sub looks great ....... how many coats of epoxy did you apply to the mdf prior to painting and do you then see any difference in absorption between a machined edge vs untouched board?

Also as an FYI, since your liking the water based top coat these days, here's something you can check out next time you want to do a quick and dirty paint job. https://generalfinishes.com/retail-p...rniture-paints. Put a few coats of the water poly on top and your done, you can also mix the colors to make something custom as well.

[JonMarsh]

I used two coats of epoxy- West systems, with 208 hardener. Of course, the edge absorption thing is always the big deal with MDF- I think it varies a bit depending on the quality/grade of the material. Do you mean the absorption of the epoxy? I suppose you could do it with just one pass, but I'm a little OCD and like to make sure I have good coverage- and it does tend to get absorbed on the edges more, noticeably so on the first pass. As you can see, the plinth base, made of three layers of MDF, shows no sign of the layer structure through the paint- that's a combination of cutting/trimming after the layers are glued together, plus the epoxy, plus the follow up sand.

I doubt that I'm a very efficient wood worker; if I knew more I could probably figure out how to get good results with less work; that's the mark of a true expert. In my case, I'm just happy to get fairly good results.

Thanks for the paint link- that looks like it could be very usable. The Rockler in Pleasant Hill is listed as a dealer, so at 12 miles away, I have a possibility for those times I don't have the patience for ordering online!

[Steve Manning]

I used two coats of epoxy- West systems, with 208 hardener. Of course, the edge absorption thing is always the big deal with MDF- I think it varies a bit depending on the quality/grade of the material. Do you mean the absorption of the epoxy? I suppose you could do it with just one pass, but I'm a little OCD and like to make sure I have good coverage- and it does tend to get absorbed on the edges more, noticeably so on the first pass. As you can see, the plinth base, made of three layers of MDF, shows no sign of the layer structure through the paint- that's a combination of cutting/trimming after the layers are glued together, plus the epoxy, plus the follow up sand.

I doubt that I'm a very efficient wood worker; if I knew more I could probably figure out how to get good results with less work; that's the mark of a true expert. In my case, I'm just happy to get fairly good results.

Thanks for the paint link- that looks like it could be very usable. The Rockler in Pleasant Hill is listed as a dealer, so at 12 miles away, I have a possibility for those times I don't have the patience for ordering online!

I was wondering about how the paint absorbed when you applied it after the epoxy ....... just wondering if the machined edges still suck the paint up faster than the non-machines surfaces was all.

[---k---]

You know. I don't read very well. I remembered the old 10" UM w/ Passive Radiator design thread. I was reading this thread all along thinking it was the same. :doh:

[JonMarsh]

I was wondering about how the paint absorbed when you applied it after the epoxy ....... just wondering if the machined edges still suck the paint up faster than the non-machines surfaces was all.

No, that's the point of the epoxy coat- it makes a sealed impervious surface, when done properly- the best way to go with PSA veneer, and also for painting, as the surface is quite non-porous then. The machined edges suck up the epoxy a bit more than the rest. But once two coats are on, and sanded, (150 then 400) it's like painting on fiberglass.

[JonMarsh]

You know. I don't read very well. I remembered the old 10" UM w/ Passive Radiator design thread. I was reading this thread all along thinking it was the same. :doh:

That one is more about the SW223BD01/2 and PR's, though one of the test cabinets is one that's sized for the UMAX 10, though it's a version that comes with a blank baffle. Heck, I can't even keep track of all this stuff, why should you be able to? :W

[Steve Manning]

No, that's the point of the epoxy coat- it makes a sealed impervious surface, when done properly- the best way to go with PSA veneer, and also for painting, as the surface is quite non-porous then. The machined edges suck up the epoxy a bit more than the rest. But once two coats are on, and sanded, (150 then 400) it's like painting on fiberglass.

Cool that's what I was looking for, a good way to seal mdf prior to paint or what ever.

[JonMarsh]

BTW, some pics of the 4 cu ft enclosure, double braces across, and space in the back where one could install a plate amp, maybe even a sub enclosure to seal it off.






This wasn't available when I started this project for GF, and it's larger than she would have cared for- but something to consider for future builds.

[TEK]

I assume that the epoxy method only work when applying paper backed veneer with psa or when using contact glue?
For raw veneer this is probably not the way to go?

[Hdale85]

I built a UMAX 15" as well but went with the Bash 500w amp and the amp is giving me issues....keeps shutting off due to heat? Not sure what I'll do to remedy this or weather to just buy a new amp. I doubt I'd go for the Hypex amp as I believe it's pretty pricey. All in all I love the sub when it is working. I haven't had the amp cut off when watching a movie, just bass heavy music.

[Face]

Go with a proper pro amp instead, the additional head room is worth it.