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Discussion Starter #1 (Edited)
Hey All,

I just tested my room with my new Umik I bought. Now It seems the room is pretty bad in the sub 200hz department.. I read the guide but I only went to 20K on the one graph. I can make new measurements tomorrow probally for now I will post what I have and see what the experts have to say..

The Room is 19' x 12' x 8' LxWxH. I have a DIY sub with a Mach 5 IXL 18.4 driver with a iNuke 3000DSP in a 12cu. ft. box with a 17hz tune..

neph sub umik.jpg

Neph umik Full range.jpg

View attachment neph 3 umik.mdat

DSCF3027.jpg

DSCF3028.jpg

DSCF3029.jpg

DSCF3030.jpg

DSCF3025.jpg

I have real bad speakers and was going to build some new speakers from DIY Sound group.. I made the measuremnts to see where I need to improve and from what I can tell I need some helb with the Sub and the Highs seem to drop off real bad..

I was wondering what room treatments or what I can currently do to clean up the below 300hz..
 

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Are you going to use a minidsp or some correction? Minidsp is a great choice. If not, your only options are phase/placement to address any anomalies. You’re going to want to rescale the graph to 45-105db(60db window) as it’s a generally accepted standard. Actually the full range sweep looks pretty decent to my eye except one huge discrepancy. I’m not sure how a 12cuft tuned to 17hz is on its face at 30hz. Plz correct me if I’m wrong but that driver is designed for car audio, no? Usually their fs is around 30hz and I’m curious how you modeled this driver for the enclosure. Do you have a high pass engaged on the inuke maybe? It looks like a filter at 30hz with a steep slope. If this is for movies, you are missing out!
Edit:

Ok. So I went and looked, but when I click t/s parameters I see nothing. ??? Anyway, I probably underestimated this driver, but definitely check the amp settings. You should be getting response much lower than 30hz.
 

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Discussion Starter #3
IXL-18.4

Thiele-Small parameters:

Fs = 17.7 Hz
Re = 3.4 ohms[dc]
Le = 6.09 mH
Qt = 0.37
Qes = 0.39
Qms = 5.59
Mms = 434.34 grams
Rms = 8.69 kg/s
Cms = 0.184 mm/N
Vas = 274.1 liters
Sd= 1029.22 cm^2
Bl = 20.51 Tm
Lp(2.83V/1m) = 91.60 dB

I do believe the IXL 18.4 is for HT use.. I had gotten the design from the guy at Mach 5 he designed the box I just used that as it was perfect for me at the time..

I am a total noob and do not know what I need to get the readings fixed.. I will recheck the PEQ on the iNuke as I was in there messing around and might have killed the 30hz by mistake..

As for the Mini DSP will that correct some issues I have?? I will check the 30hz problem now.. but I followed this guide to set the inuke below 20hz:


http://www.avsforum.com/forum/155-diy-speakers-subs/1461489-how-extend-high-pass-filter-below-20hz-dcx2496.html

It does go down low just not to sure why it dipped in the 30hz range there??
 

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I think the minidsp has a lot of potential to fix your issues but placement is the first thing to address, and really, I don’t see anything really terrible other than that weird roll off at 30. Curious what you find in the settings.
 

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Discussion Starter #5
Well I checked the settings in the iNuke I did not find anything that looked like it would make that dip..

I am unsure what is going on, but could it be a blown speaker or the iNuke itself going bad?? I did another reading and it looked the same with the dip in the 20's??

I sure hope it is just a placement issue but it is in the right rear corner woofer facing into the room??


subdip 20's.jpg
 

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Discussion Starter #6
Well I done a bit of reading and placement seems to be the best bang for the buck. But the only problem the subwoofer is a monster and weighs a ton.. I will need help moving it..

I was wondering if the speakerside should face into the room or at the rear wall?? I could try moving it myself to a more frontal position??

Not sure what to do but I know I need to do something.. Will go read some more threads here and there but hopefully I can get this solved..
 

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Discussion Starter #7 (Edited)
Well I turned the subwoofer to face the rear wall and back a bit to about 6" from the wall.. It did not help the Null was still there..

OK I just tested the mic on my PC it seems to be working just fine. I think there might be something wrong with the speaker itself..

I moved it around the null should have responded some way as placement seems to fix some issues..

I really have no idea what is wrong I just wait for someone to chime in and maybe has an idea what is wrong..
 

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Take the sub outdoors. Sweep it out in the open. No room affecting it. If you get the same or similar curve my thought is that sub it tuned around 28-32 hz. Take it outside and do a measurement. Middle of driveway with nothing around maybe. If that drop is gone it’s a really bad room null. It really looks like it drops off from a high tune though. Make sure you sweep inside with only the one sub. Ensure no other sources are present.


Sent from my iPad using Tapatalk Pro
 

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Discussion Starter #9
Well that is the thing the sub is very heavy and I really don't feel like moving it outside if possible..


Thing is this sub is supposed to have a 17hz tune maybe I am not totally getting it but is this not a HT Sub?? Maybe it is not even a IXL 18.4??

I have to think that could be possible too?? If it was a Mach 5 IXL 18.4 would it be stamped on there somewhere??
 

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You either have a HPF engaged or that box is tuned to 30 Hz, be it by design or build flaw. The rise below 20 is room gain, the content itself in free air would continue to fall off. If you don’t want to take it outdoors, then the safe assumption is the box build or a filter.


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Discussion Starter #11
Well I tested just the sub from 10-200Hz. I ran REW with the Umik Pointed at the Subwoofer about 6" and the correct calibration file loaded and got the following reading, this was with no filters or EQ in the iNuke:


subonly.jpg


I did set the HPF filter on the iNuke but I read a guide on How to set it below 20Hz it should be set to 16Hz?? the above graph does look like the Sub is working as it should?
 

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Discussion Starter #12
OK I ran some more tests to day. this is the lates w/Front L/R + Sub graph.. I did the test from 2 - 20KHz but modeled the JPG for the sub Only..

AS you will see I still get a null from around 20-26hz?? I am unsure what is going on there as the separate sub test showed the sub is working at least I think it is Working Properly just that void there when doing the full test..

Does the above graph the post above this one show that the subwoofer is tuned at 17Hz ??


new sub.jpg
 

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Discussion Starter #13 (Edited)
OK I was making some mistakes with setting up REW.. I do believe I corrected them and have some new mdats.. I took 2 measurements and made notes in the files I saved..

One measurement was at listening position and SUB ONLY.. the 2nd was taken at 3feet from speaker center cone with the mic..

I made a mistake with the Mic setting I was setting the mic gain too 81 and it needed to be at like 10 or under.. I thought the laptop had Win 10 but it has Win 7 so I goofed there probally why they read so high..

I corrected that and here is a SPL Graph with the new measurements. they look similar but not as high DB wise..

both measurments.jpg



here are the 2 mdat files incase anyone wants a more detailed look:
https://1drv.ms/u/s!AgDOJnMP-19IqSO0RBRxsnLpx4Yd


EDIT: I was rereading the faq and guide I was able to get Asio working last night. In the Guide it states to test the Speaker front L w/Sub?? Is that still how I should do it for a Full range reading??
 

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Discussion Starter #14
I had made some adjustments in the PEQ and came to a better graph.. here it is:



subflat.jpg


Now I read some of the guides especially this one:

http://www.hometheatershack.com/forums/rew-forum/6818-minimal-eq-target-levels-hard-knee-house-curve-long.html


I followed along and did as he described there to use a 1.6 smoothing and EQ it. From what I can tell I have an improvement from where I started.. I think the Subwoofer is about as good as I can get it from all I see and read..

Now should I bother measuring the other speakers in my system or would that be pointless as I plan on building some DIY Speakers??

Now a Couple of the measurements I had some configuration issues but currently I have Asio4all working on the laptop. I can now test all 8 channels.. I have a 7.1 system..

The One thing I don't get yet in the setup guide it states I should be able to set the AVR to 7.1 channel input which when I do I hear no sound.. I have to set it to TV on the AVR.

I am curious to know why I can not use the 7.1 channel input like when I run my SACD/DDVD-Audio Player Denon 1930ci?? Is this mode not the same they talk about in the setup guide that I set on my AVR Marantz 4001..
 

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Discussion Starter #15
OK Moving on I made some more measurements just a minute ago and mostly it was for measuring for the distance setting which I was able to do.. I was able to see what the distance was and set the Reference Speaker that was closest to the mik..

But I imagine these are good for regular measuring. The measurements are made at Main Listening Position and at 75DB SPL Reading..

I double checked the levels and set them as I think I finally figured out how to set it up correctly..

From what I was able to discover setting the levels the AVR is supposed to set the Main Volume Automatically but with my receiver I have to adjust the Main Volume to get it set..

So the Problem I am having is trying to figure out what to set the Main Volume Level at.. I seen some say to set the MVL at ZERO but that seems way too loud..

Soon I am getting a new AVR With Audyssey and that should not matter anymore as the newer AVR Play the Pink Noise at a Set level..

Here is the mdat in case anybody wants a peak.. Remember these are the speakers I will be replacing.. Right now I tuned up the sub a bit and it goes down to 16hz preet loud now..

Now sure what else to do with REW and this post seems a bit slow so hopefully I can get the new AVR in January and get the new speakers started in Feb... Still trying to decide what DIY Speakers to get.. I am thinking maybe those bookshelves I saw a DIY Group..


https://1drv.ms/u/s!AgDOJnMP-19IqSb1VyjwaeQfb8gh
 

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Discussion Starter #16
Hi All,

I was wondering if anybody still visits here in the REW section of the Forums.. Been kinda quiet here last week or so..

OR is it because of the Holiday..?
 

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Discussion Starter #18
So do you think I will need any room treatments?? did you see the sub measurements I took?

In the MLP there was a dip but when I measured from about 1foot away from the subwoofer it looked fine, Do you think there is some sort of cancelation thing going on with my sub..

I did try and move the sub I even turned it 180 facing the rear wall about 1 foot.. IT still looked the same with the dip..
 

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If you’re talking about the dip seen in Post #13, it’s caused by the sub’s interaction with the room. A different location might take care of it. Typically best response is achieved with the sub in a corner with uninterrupted walls in both directions (i.e. no open doorways). Typically there will be a peak in response, but that is easily dealt with via parametric EQ.

Just noticed your pictures from the first page of the thread. I’m shocked that such an impressive sub is dead in the water below 30 Hz. What happened to the 17 Hz tuning?

Regards,
Wayne
 

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Discussion Starter #20
If you’re talking about the dip seen in Post #13, it’s caused by the sub’s interaction with the room. A different location might take care of it. Typically best response is achieved with the sub in a corner with uninterrupted walls in both directions (i.e. no open doorways). Typically there will be a peak in response, but that is easily dealt with via parametric EQ.

Just noticed your pictures from the first page of the thread. I’m shocked that such an impressive sub is dead in the water below 30 Hz. What happened to the 17 Hz tuning?

Regards,
Wayne
Well that is exactly what I been trying to determine with the sub.. Either the sub is broke or it is not the sub I thought it was..

I really do not know what to do.. The sub is supposed to be a Mach 5 IXL 18.4 with a 17hz tune.. I do not believe there is any markings on the sub itself so either the sub is broke or it is a fake..
 
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