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Discussion Starter #1 (Edited)
I finished my home theater about 6 years ago, and have loved it ever since.(layout here) The one area that I am still not 100% satisfied, however, is the subwoofer. I just don’t get the deep bass “feeling” I was hoping for, and I assume it’s because of the larger space coupled with an open back wall. I went DIY on my speakers and built one UXL-18 in a sealed case and 3 Tempests. The sub is powered in an inuke3000.
At this point I see 3 possible solutions:
  • Replace the sealed enclosure with a ported enclosure for the UXL-18. I probably should have gone that route initially, but I think was worried about size. (I just measured and I have about 2’ 6” width and 3 feet depth available on my front stage (x2 if I add another subwoofer). Perhaps the full marty?
  • Buy another 18” driver, and put it in a sealed enclosure. (Ideally I’d buy another UXL-18, but they are currently out of stock on Mach 5 audio, and I have no idea when/if they will ever be in stock.) I would place them both on my front stage in between the three tempests.
  • Buy another 18” driver, and mount both in ported enclosures. (My understanding is that mixed subs in ported enclosures work better than mixed in sealed enclosures. I would place them both on my front stage in between the three tempests.
Any advice would be greatly appreciated. Thanks!
 

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REW will tell you what is going on. It's a good tool.

A rough guess is that you need some EQ but that no amount of EQ will make up for not having enough output.

It is not an exact prediction but often using a large ported enclosure can DOUBLE the low frequency output versus the same driver and amp in a sealed box.

So I think it's a great idea to re-do that sub into a larger ported enclosure.

And a second sub, while that will increase output a bit, will have the main benefit of giving you more consistent bass across multiple seats.
 

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Discussion Starter #3 (Edited)
Thanks. I now remember that I went with the sealed sub because that was the only flat pack available at the time. The full marty flatpacks look great. I think I'll start with the rebuild and the room EQ and see if that takes care of my needs.

Regarding a second sub to match with my UXL-18 (ported), any suggestions? The UXL-18 with no availability is making it less appealing. I see the UM18-22, LaVoce SAF184.03 .
 

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Discussion Starter #5 (Edited)
Any other opinions on this? It's not looking promising to secure another UXL-18, and I'm thinking I should go dual subs. So the current thought is: would it be ok to mix my UXL-18 with a Dayton UM18-22, and run them in matching sealed cubes or matching Full Martys? The UM 18 can push 1000 watts RMS, and the UXl-18 can push 1200 watts RMS. Matching sealed cubes would be easier since I already have one completed, and apparently would give me better low frequency bass. I would power them with a Behringer NX 6000. My UXL-18 is 4 ohms, so I assume I would need the other to be 4 ohms as well.
 

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I felt the same with my dual 15s so I got a UM18. It hit hard low and for a very short time I was impressed but the midbass just wasn’t there and it just felt like something was missing (especially with an 18” driver which at the time I bought it seemed huge). I was told to add a 2nd UM but I wasn’t sold on the idea.

To get the tactile feeling on a slab requires a lot of force. I’m not familiar with your driver so I cannot comment on it. With only 2 subs I would definitely look at one of the devastator designs. After I built my first Lavoce 21” San devastator I knew it was what I was looking for. At least equal low end as a UM but on a completely different level with midbass and gave me the tactile impact I was looking for (2 UMs cant keep up with one 21”LaVoce SAN devastator in the midbass region).

I also built 2 18” SAF Devastators and they hit hard too. An NX6000 can drive two. I have 2 21” SANs driven by one Crown XLS 2002 and they pound.
 

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...After I built my first Lavoce 21” San devastator I knew it was what I was looking for. At least equal low end as a UM but on a completely different level with midbass and gave me the tactile impact I was looking for (2 UMs cant keep up with one 21”LaVoce SAN devastator in the midbass region)...
Could you post your in-room frequency response? I am running two SI subs in 10.5 ft³ tuned to 16 Hz., and would like to see what I may be missing.
 

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Can you guys explain for me what you consider 'mid-bass'? A lot of 'mid-bass' drivers run right up to the tweeter, and I know a lot of classic 3-way designs where the woofers run up and meet the midrange at about 500 Hz. In such a context, in terms of octaves, the middle of the bass would be 160-200 Hz. My guess is that you're not referring to this range.

I can understand, certainly, a more efficient driver being more proficient in higher frequency ranges as it isn't intentionally mass-loaded to 'naturally' extend low without the help of EQ. I get that part.

But as far as the mid-bass on a UM-18 not being 'there', I need some help wrapping my head around what you guys are experiencing. I certainly had some initial issues with the UM-18s I got in terms of integration. It sounded bloated, disconnected, kind of just floating out the separated from everything else, but it turned out to be mostly a phase-related issue that was coincidentally corrected with a rough approximation of a Linkwitz transform on both the subwoofer itself (to flatten the hump) and the 8" woofers it was meeting at 80 Hz. That undoubtedly had some impact with frequency response, but in terms of the range that the UM-18 were nominally responsible for, up to 80 Hz, it was all there even before I fixed it, the only thing that improved was the splice between them.

The data-bass.com website measured them behaving well up to 166 Hz, and above that, their response rose. Same website measures them handling the 117 dB nominal level at 30 Hz and up without any significant issues. I am in no way suggesting that better cannot be achieved than the Chinese bang for the buck mass-produced special. I am just curious as to how it's falling short, objectively speaking, and how that's related to what you're hearing. Is the dynamic range capability just short at higher frequencies for the application, like you're playing pretty darn loud in pretty darn large areas at pretty decent distances? Or is it a subjective feeling of 'not quite there' at all levels?
 

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Could you post your in-room frequency response? I am running two SI subs in 10.5 ft³ tuned to 16 Hz., and would like to see what I may be missing.
Sure but it may take a little bit. I’m having an issue with the HDMI connection on my PC and waiting and hoping the new cable ordered will resolve the issue. From memory somewhere above 40Hz and above has to be brought down significantly for a house curve.

Can you guys explain for me what you consider 'mid-bass'?
Midbass is a term I picked up from other comments here which I would classify as somewhere around the range of 40-100Hz. If you model a pro audio driver like a PA460 vs a UM you’ll notice that somewhere around 30Hz and below (going by memory) the UM will take the cake, whereas going up in frequency the PA460 will start having a huge advantage. To be fair, I only had one UM in a box a little bigger than a mini Marty but I did try different locations, boosts/cuts using REW and a mini DSP HD and no matter what I did some bass notes just didn’t have the impact like they did with one of the Pro Audio drivers I tested. I feel as if the UM and PA460 are good examples of this as both have the opposite strengths and while a mini DSP can help get the most out of each of them, in the end a PA460 isn’t capable of the low end that the UM is and the UM can’t reproduce midbass like the PA460 can.

For me, it’s more of a tactile/impact feeling than it is for hearing a loud bass note (if that makes sense).

If this was just my experience I might question my results or perhaps my experience is based off of my rooms response but when you look at GSGs performance chart it pretty much says the same. I also followed JMAX’s thread of “4 UMs aren’t enough” who received help from who I assume to be one of the more knowledgeable members on the forum who helped him dial in his system and he was happy for a short time but eventually replaced all 4 with NSWs which gave him the slam he was looking for (along with a new amp too and I know that’s not exactly a fair comparison), but I’ve seen many other complaints about the UMs lack of midbass but you never see that complaint about pro audio drivers. All 7 pro audio drivers I have pound in that area the from the moment I used them without any EQ and after a house curve was applied. The devastators are a prime example of this - if you look at a model you’ll start seeing a dramatic rise at about 25Hz on up with about a 15dB jump on some models. The downside to the devastator designs may be if you are looking for bass down into the teens or lower as I don’t believe any of the devastator models have HPFs set below 16Hz.

I have my subs crossed over at 100Hz and I’ve yet to integrate them with my mains (I’ll save that learning adventure for when I get my room construction completed).:)
 

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Midbass is a term I picked up from other comments here which I would classify as somewhere around the range of 40-100Hz....
I think that makes sense. Playing with parametric EQ settings, it seems that emphasis centered about 60-65 Hz is where you get your 'kick'. Maybe that's also more of the range where the human body resonates as well. I also find that after I set up driver correction/integration for the flattest response, when I adjust the curve with global EQ, I blend into the generic 'bass' control a lower frequency bass shelf filter with a turnover at 125 Hz, as well as a parametric peaking filter centered from 60-65 Hz, depending on how it interacts with the room/driver combinations. This has been drastically beneficial to me from a subjective standpoint, including a bit of what I think is being described, that 'tactile' impact sensation, regardless of the system.

However, I don't think most people have access to highly adjustable global EQ in their setups, (hence possibly why often the subs ride 'hot'), and if you start EQ'ing the subwoofer alone merely for subjective effect in it's higher range and aren't careful, you start screwing with the phase relationships at the crossover point, and if things were working well in that regard, they can fall apart, giving the impression that the EQ not only didn't fix anything, but made things worse.

But even so, in terms of what you're talking about, I was also looking at the compression curves of the Ultimax 18, and in that regard, it seems a little bit like a one show pony when it comes to dynamic range, at least as it was evaluated, in that it doesn't compress much at all at 33 Hz, which is probably the frequency of the most impressive 'BOOM' that is still reasonably audible, but it backs off compared to high-efficiency, very high-power handling units substantially moving away from that impedance peak, probably because the coil is heating up a whole lot more. This would change the tonal balance, as well as the dynamic performance. Maybe that's the brunt of what people are noticing. In the most recent units I received, they aren't even like that sample, and as such, I would expect that the prize pony is centers closer to 39 Hz, but the principles would be the same.

You could EQ to compensate for the frequency response (and if you're careful to take into account integration with the main speakers, get some good benefit, or if not just make it worse) but you can't EQ out the compression, or for that matter compensate for the frequency response shifting at higher output levels. If you could program that into the Dynamic EQ present in some room 'correction' systems, that would certainly help. It wouldn't 'correct' the dynamic nature of the behavior, only compensate, and while the playback level settings might be some kind of predictor as to what kind of compression effects to expect, it doesn't really know the program content and how that would interact thermally.... So maybe throw that idea in the trash, or at least shelve it as a experiment to kill time.

But anyway, thank you for explaining that. It makes a lot of sense.
 

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...But anyway, thank you for explaining that. It makes a lot of sense.
(y)

Kinda feel bad pointing out the faults of the UM as I know many love them and they are good drivers. I just think many aren’t aware of what they are missing out on with only UMs. I tried EQ and with my tests it just didn’t seem to help enough like you said. When I tested instead of just focusing on the MLP I stood right next to the UM on a suspended floor and the impact difference felt on the floor on many bass notes vs. a dual PA460 was very clear (much more than I expected even though dual drivers is a big advantage). The difficult part in all this is you pretty much have to buy and build to really know what you are getting as this isn’t something you can just go to the store and make comparisons.

If you want to see what you are missing out on the cheapest way to see is by adding a PA-460. You can get one for about $85 with a PE coupon and you only need about 350-400 watts to power one up.
 

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Could you post your in-room frequency response? I am running two SI subs in 10.5 ft³ tuned to 16 Hz., and would like to see what I may be missing.
Sorry for taking so long to respond. My HDMI cable for my computer was bad and the replacement finally showed up a couple days ago and I couldn't take any measurements without it. I'm reworking a lot in my room and I've pulled all seating out of my room except 2 seats so I cleared my previous settings and ran some quick measurements and changed the timings to ensure all summed without any losses - too much is being changed to dial anything in at this point. I was surprised to see the drastic jump at 45Hz on my SAFs as no other measurements in the past were quite that drastic. Having said that here is what I have.

Red - Dual LaVoce SAN 214.5's in V5 HCR Devastators up front - bridged off of one Crown XLS2002
Gray - Dual LaVoce SAF 184.03's in modded V7 HCR Devastators on the sides (1.5ms delay) - bridged off of one Crown XLS2002
Blue - Solo NSW 6021 in a Finalizer V2 in the back left corner (4ms delay) running on a Crown CTS3000 bridged +5dB Mini DSP + higher gain setting on the Cleanbox Pro
Green - Summation of all. No EQ on any of the subs.

3077435


Hope that helps!
 

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Is this the measurements of just the subwoofers by themselves? If so, do you have information with response with the mains integrated as well?

You mentioned delay, are these set so that woofers are aligned at MLP?

To about 55 Hz, the summation looks great. The flat plateau is interesting, but looks like it is simply the sum of two peaks having to do with the combined room response. You may choose to address that with a couple of parametric EQ cut filters globally to flatten it out later after seeing. What is interesting is that you have that roughly 85 Hz notch, which not only seems related to something the room is doing, but because the green line is actually lower than part of the grey line near where the blue and grey intersection in amplitude, implies that the blue and the grey may have some phasing differences. Whether you can or want to do anything about that, I don't know, but it might make a little sense to at least try applying a 'treble' shelving boost on the grey line subwoofer, maybe 6 dB or so with a turnover of 70 Hz or so to see if that can fill in for you a little. It will not only make the blue and grey output less equal, but it will affect the phase response. It may simply move your notch in a different direction (I would guess up, if it does), but you never know until you try and see, and maybe if it does, it will move it to a place that the main speakers can cover up anyways. Try, see, listen, repeat until satisfied.

As a general process regarding subwoofer integration, I like to run the process to get the drivers to do what they 'should' first, so that even before the room gets ahold of them to screw up what you hear, they've got a chance out of the gate, optimize room placement for flattest response, trying to duck peaks and nulls, set time-alignment between drivers, apply crossovers for flattest summation and phase alignment (which may mean revisiting driver response correction), then apply global correction to flatten the whole room response. Why global? Because if I try to correct the room by just selectively targeting drivers, even drivers that dominate that range, it can change the summation with other drivers, which may or may not introduce other issues. I'm not saying it cannot be done well another way, just my reasoning for my own preference. I don't necessarily push for the flattest it can be, but in that direction, and from there, once I know that I'm getting ALL the frequencies I could want to hear, apply EQ to taste, playing with different content to see what sounds subjectively 'good' to me, and measure it from time to time to make sure I'm not doing anything seriously whacky. I might even see if backing off on some of the room correction settings sound subjectively better or more 'natural'. But I think I'm getting kind of redundant...

My point being, , once you've got the response so you know you actually have access to the whole frequency range, and can hear what 'flat' sounds like, and most likely verify that with most content is sounds pretty unimpressive, regardless of low frequency extension limits, play with some content, maybe electronic dance music or anything really, so long as it has regular and even low frequency content that you can use to judge the presentation you're after, and play with the center frequency as well as amplitude of a global parametric EQ boost to figure out the 'sound' you want to enhance. When you can correlate the subjective effect to numerical values, it saves a bit of tail chasing when it comes to drawing your final (or default) curve.
 

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Right now that was just a measurement of the subs only without any EQ. I just set delays to get the best summation in about 15 minutes. I'm in the midst of room modification so I'll save that for when I've finished. The subs are mostly where they will be with perhaps a slight ****ing a little. The integration with the mains will be another project and will be a learning experience for me. I have a mini-DSP which applies EQ to all of the subs but perhaps it might be best to also learn MSO for the best overall room response. A lot of work to do first before I will be able to get to that. The curve is definitely midbass heavy and will have to be toned down. Even when I do have a house curve when the volume gets a bit louder the curve starts to flatten.
 
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