Ultimax 18 mechanical noise and distortion test
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- Опубліковано 23 сер 2024
- I have to say I am very impressed with the Ultimax 18, I didn't really expect it to be this good. It's more than just a woofer that can remove items from shelves in the next room, it's also a high performance woofer with low non linear distortion and next to nothing in mechanical noise.
I just got one of these the other day and can't wait to set it up. I really appreciated the video. Keep up the great work!
Yeah I'm really impressed with it, I never expected it to have that much excursion without making noise, it's pretty amazing!
Thanks for the mechanical noise test results.
The actual speaker looks light, it seemed like the magnets magnetic attraction to the metal stool was a strong force but once that magnetic attraction broke away the speaker itself seemed to be light.
Cool to see your distortion measuring setup. I was going to say your 2nd harmonic distortion will go up (air spring distortion) once you put the drivers in a box but your IB setup probably has enough air space where this won't matter.
I may have mentioned this in another of your videos ... my Ultimax 15 were an absolute disaster .... they very quickly failed when pushed at low frequency namely 20hz
Using IB24s now and there is no comparison |
I hope you have a better experience with them
GREAT JOB
6 in the attic?! You can tell people to look for the house with the roof popping up and down when giving directions.
Was my plan 6 back then? I put in 12.
No baffle, inside a room with a lot of reflecting and resonating things. Is the distortion measurement even useful in that situation? Not being critical, only curious. I typically see distortion measured outside with the woofer in a box.
Ideally yes but the mic is relatively close to the driver and any near by reflections should have about the same content of fundamental and harmonics so it wouldn't make much difference. Basically the reflections are both attenuated relative to the direct and also very similar to the direct sound so not much contribution to the total. No baffle is an advantage, no off axis radiation to reflect off the walls. But yes, you are correct, ideally away from reflections is better.
Measuring a more full bandwidth frequency response however really needs to be away from reflections. Now that I've moved into a place with more room outside I finally have room to do outdoor measurements again, didn't really have a good place to do it when this was done.
@@mfkhometheater7742 Good to know. I am doing research on potential theater subwoofer upgrades and am having a hard time finding science-heavy info. Rattling wall videos are only amusing for so long.
@@dustind5176 I know what you mean, before I ordered and tested mine the only thing I could find were those kinds of reviews. Thing is, any big driver with a lot of excursion can shake the walls so those reviews aren't telling us anything. The real question is, can it do it with low distortion and low noise. No one seems to address this and most don't have the equipment to measure distortion even if they wanted to. The Umik microphones from miniDSP and mics from Parts Express can't do it because the microphones themselves have too much distortion. It takes something like the Earthworks or a B&K to do it but these are far more expensive than the Umik.
Btw, I have eight more 18" Ultimax drivers coming. I was going to order seven to go with the one I had but because of the price break at eight, it wasn't much more to just get the eight. I guess the extra will just be a spare... or maybe a subwoofer for the down stairs TV:-) The eight will be in the attic above the theater in an infinite baffle. The plan is to mount them magnet to magnet with a spacer between them to keep the pole vents open. This will cancel mechanical energy so nothing vibrates. The plan is to use these for single digits to about 27 Hz and use open baffle woofers each side of the screen, eight 15" woofers in each floor to ceiling column. The dipoles can handle 27 Hz to 80 Hz.
@@mfkhometheater7742 Have you considered mounting them cone to magnet? Any mechanical nonlinearities get cancelled out due to the inverted polarities (one moves away from the magnet while the other moves towards the magnet). Another benefit, if I remember correctly, is it reduces 2nd order harmonics.
Most folks don't/can't do it because of mechanical noise, but, if the UM18 is quiet enough, it could be a possibility. Also, some drivers are so linear when looking at Klippel measurements, inverting one woofer doesn't result in as great of a performance gain.
That said, if you like to tinker, it could be worth setting up a test rig to see if turning one woofer around provides a measurable improvement in distortion...?
*edit*
Come to think of it, you have a huge volume of air you can move with 16 total woofers. The cone excursion is likely going to be fairly low and thus low in distortion anyway. Inverting half the woofers may not even amount to much gain just because no single driver will ever be pushed hard.
@@dustind5176 You do remember correctly, it does reduce 2nd harmonic distortion. As recently as 2015 I was mounting woofers with one reversed but I started thinking that I might be better off to keep that 2nd harmonic to help mask the 3rd harmonic which isn't decreased.
Back in the early 90's my brother Marshall and I did the experiment with two 12" woofers in a sealed box and it did dramatically reduce the 2nd harmonic. At the time we didn't think about this being less masking for the 3rd and we continued to mount woofers with one reversed. I think Marshall may have done it even more recently than me. Siegfried Linkwitz always mounted them with one reversed and I don't think he ever changed that. If I remember correctly Brian Elliot didn't do it that way when he used conventional 12" drivers. Now days he uses cheap 10" drivers coupled to large cardboard panels and those things produce the cleanest bass I've ever heard. At 16 Hz the 2nd is something like 55 ~ 60 dB down and the 3rd around 65 ~ 70 dB. Brian is the guy that taught Siegfried about open baffle speakers but unfortunately Brian has no internet presence. The guy is 92 years old and still doing DIY speaker building though so you have to give him credit for that:-)
Yeah the idea of having so many woofers is to have more surface area and less excursion so with sixteen 15" limited to 27 Hz they shouldn't be a problem and the eight 18" being in infinite baffle instead of dipole also should provide plenty of output with very little excursion.
May I ask the model number of 15" from Newark you will be using? I would like to get some as well for a open baffle setup.
The plan is to use eight of them on each side. I'm using the 8 ohm version so they will be in parallel pairs with an Emotiva BasX 4-ch amplifier for each column of eight woofers.
They will be mounted magnet to magnet with a spacer between that's open so as not to block the vented pole pieces. Each pair will be vertical, one facing up, one facing down with the cone front sides open to the room and the magnet sides open to the rear. This cancels the mechanical energy in the frames. You have to be careful though, you want the open area of the baffle to be at least as large as the cone areas so it doesn't accelerate the air. In the back it's already accelerated by the relatively small openings in the frame so the back opening only needs to be as large as the openings in the frames.
@@mfkhometheater7742 Wow that will be amazing.
So many I ask what model of Mcm driver 15" for that you will be using?
@@jordenb9469 www.newark.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=15003&productSeoURL=mcm-audio-select&partNumber=80R7013&storeId=10194&langId=-1&krypto=TpKkbLv5LYuiVk3OTBCxsdj%2FncoEvpTQSvZaSWOFq8ggNSda03jzQKWKgqxth%2F%2BF4vs10GXM37ozTqfwxx0LUA%3D%3D
They're cheap but in open baffle they sound amazing! I use two of the 12" version in my 2-ch system and have gotten lots of compliments on the amazing bass quality. No one can believe that the woofers are so inexpensive and sound that good. I wouldn't use them in a box design however, the Qts is much higher than the spec so they wouldn't work well in any box system, just open baffle or infinite baffle.
@@mfkhometheater7742 Thank you. Would be great if you put your finished build on UA-cam.
Thanks again.
@@jordenb9469 Oh yeah, once I get it all built I'll post it. Right now I'm in Dresden Germany so not getting anything done on the theater. I did a little bit before this trip, mainly building the frame that will support the screen frame. I might put together an update later with some photos of that. I'll be taking the last two weeks of this month off work and hope to make a lot of progress on building the speakers.
Can I run 2 of these in my SUV in a 14.4 cu.ft ported enclosure, tuned to 31Hz on 5500 watts RMS? I have 2 18s already that has great SPL, i’m just looking for something with a little better sound quality
I'm going to run one 10 ported 1.5 cubes ,on 600w in my civic.
What is your favorite woofer? Thanks
Don't know if I have a favorite, it just depends on the application.
Hello. Can you please make a video on your Altec Voice of the Theater loudspeakers? They look very interesting. Thanks
Hopefully someday, right now I'm still just trying to get the theater up and running. I have such limited time due to my work travel, it's taking forever to get that done. Still, it would be cool to do a video telling a little about the A7's, they are some pretty nice old speakers.
My brother and I built the cabinets and I bought all the hardware on ebay. I bought drivers that were in need of repair and shipped them to Great Plains Audio to be reconed with original Altec cones. I figured that was the best way to make sure they were in good condition.
One of these days I would like to build a set of Altec Model 19's but I don't really have a good place to put them.