SPL vs Frequency Chart of Bedroom Icon WF-34s In Stereo Mode With RSW-15 Sub

[nola]

SPL vs Frequency Chart of Bedroom Icon WF-34s In Stereo Mode With RSW-15 Sub.

I hope I did not goof this up by testing 2 speakers and a sub at the same time. If I did, let me know.

Done with RS analog SPL meter. Blue is orig numbers, red is with SPL correction numbers from the net and green is an addl set of corrections posted on audiogon some time ago. I did not have crxn values for all frequencies. Sub crossover was set to 80 Hz. I don't know if the surround spkrs operated in this stereo mode off of the Onkyo 805. The center was not operational. Used test tones generated from my laptop - NCH tone generator and SigJenny, both free.

Also noted that higher freq test tones varied as much as 20 dB (3150 and 2000 Hz) depending on even small changes in position from 400-12500 Hz. But usually moving the SPL around a few feet yield dB readings within 5 db.This was especially variable near headboard of bed, maybe due to hard wood and brick wall reflecting the sound.

Looks like I have sonic holes at 65, 73, 400, 2K, and above 8k. I have not tried the Audisey system nor the sep spkr crxn features on the 805. Guess that's next. However:

-did I do this test correcty

- am I stuck with multiple room nodes, including the sub holes at 65 and 73 Hz?

[Colin]

cool, thanks for posting the chart

I think you have some incredible low bass extension there, that you need room treatment like RealTraps to get rid of the suck-outs and that the roll-off above 8 kHz is natural

[colterphoto1]

sounds like a reasonable test.

Run Audessy, note that it will probably set up your mains as full range'

Do your test, with your test mic in the SAME PLACE as the Audessy mic

Reset speakers to SMALL

Do your test again, note changes.

Pick your preferred setup LARGE OR SMALL

here's the kicker, move your test mic, run your test again. This will demonstrate to you that the eq in audessy (or any system) will only 'flatten' the response at that particular point in the room, at other listening positions the eq may or may not flatten the response. You'd have to do multiple audessy locations and take an average of their measured response to do the most good. Interestingly enought, that's exactly what is done to tune commercial cinemas. A diamond shaped array of mics is setup in the theater and the combination of their measurements are what is used to tune the system.

Michael

[nola]

Thanx folks.

Here is the link to the excel spreadsheet template, there is also one from aci (subwoofer folks in wisconsin), but I think this one is easier to use:

http://home.comcast.net/~thomasw_2/FreqResp.xls

It will lead to a file "FreqResp" under excel. I changed most all of the given number settings in the table and added my own. Thus my graph is actually totally different from that intended by the author. However, as I do know how to do this stuff under excel, it is the best template that I could find. It allows for 3 curves to be drawn. So my 3 curves were: SPL reading, stnd SPL crxn, and addl crxn as given below.

I added the correction values as noted below 100 HZ I added a bunch of test frequncies

Column 1: HZ,

Col 2: basic SPL correction found on the net

Col 3: from a single audiogon posting and never verified elsewhere as being correct, 1250-200 is flat or 0

http://forum.audiogon.com/cgi-bin/fr.pl?htech&983682086&openfrom&2&4#2

Otherwise, where no correction factor is listed, I did not find one. Note that the addl freqs tested were musical note freqs or other values generated by thecomputer tone generator software used. Below 15 Hz (and at 20, sort of) I was not able to yield "sound" or test tone to make a sound. I was kind of impressed by my RSW-15

20000	1	11.2
16000	0	8.5
12500	0.5	6.2
10000	-1	4.4
8000	-2	3
6300	-2	2
5000	-2	1.3
4000	-2	0.8
3150	-1.5	0.5
2500	-1.5	0.3
2000	-1.5	0.2
1600	-0.5	0.1
1250	0
1000	0
800	0
630	0
500	-0.5
400	0
315	-0.5
250	0.5
200	-0.5
160	-0.5	0.1
125	0.5	0.2
100	2	0.3
92.5
82
80	1.5	0.5
78
73.4
69.3
65.4
63	1.5	0.8
61.7
55
50	1.5	1.3
49
43.6
41.2
40	2.5	2
39
35
31.5	3	3
31
27.5
26
25	5	5
21.8
20.6	7.5	7.1
19.4
18.4
16.4
16	11.5
15
12	16.5
10	20

I will try more stuff this week and try a 5.1 test tonight and a lt or rt spkr on its own too. Will also try using the non audisey system to correct specific freqs via 805 itself.

Thx

[nola]

Repeated the test tone tests tonight. Last night was Onkyo 805 stereo mode only with subwoofer. I do not think the center channel speaker nor surrounds let out any sound. Tonight was in Onkyo 805 Theater-Dimentional mode and Neural THX (whatever that is) modes. I do tend to use these for MP3s via lappy and analog signals. I cannot test out dbx or dolby 5.1 without using digital signal source (like HDMI or optical, neither of which I can do from the lappy). Center speaker was used by the Onkyo in tonights tests, but I think the surrounds were silent. I inputed the sound via the 1/8 jack on the laptop and had splitter to 2 analog rca jacks into the onkyo

Wow, what a difference between the sound field settings. The RS SPL was in a slightly different place last night, but that alone would not explain the big to huge diffs between settings. However, many of the peak and valley areas are seen in all 3 settings.

http://picasaweb.google.com/k7100x/BedroomSPLCharts#5355938864258412274 stereo mode from 7 6 9

http://picasaweb.google.com/k7100x/BedroomSPLCharts#5355938864051597234 TD mode and corrections 7 7 9

http://picasaweb.google.com/k7100x/BedroomSPLCharts#5355938863751686402 TD and neural tests 7 7 9

http://picasaweb.google.com/k7100x/BedroomSPLCharts#5355938864494086370 All 3 modes graphed together

not sure what i doing wrong as the pix above do not show up.....

[colterphoto1]

forget about the sound field settings. just get the audessy and the room setup first. it's getting too complicated to make any sense of the last set of reading. Either correct or don't correct your findings and report one set please.

[michael hurd]

Trouble is that it's hard to quantify what is going on with the method that you used to measure. While you can get a picture of the overall FR ( sort of, I will get to that in a bit ) when you move the meter an inch and re-measure, you will get different results. Move the meter another foot, and again, you will have totally different results.

RE: measurement. Soon, you will be so confused, you won't know what to measure. As far as actual FR, we can't really percieve narrow band dips of a few frequencies. ( our mind fills that in ) Using a sweep based method and a microphone that's calibrated can give you more accuracy, as well as giving you an idea of any problems in the time domain. You can see this as 'ringing' in a waterfall plot you can generate with software and the impulse response.

Generally many measurements that are averaged can show up actual problems in the room: this is mainly how Audessy works. ( not sure of the spelling )

The software looks for trends among the averaged measurements and 'corrects' what it feels is not right. This software is not without it's bugs though. I have read a few accounts where the software mistakenly identified the F3 of the speakers it was connected to, due to room interaction.

Bottom line, if it sounds decent, it should be decent. Measurement can be a red herring if you aren't sure what to chase. Try auto correction, you may like it, you may not. More than a few people are unhappy with the results in the bass department.

[nola]

Michael, oh Master of the Home Made Sub, thanx.

Yes, I did drive myself nuts. And yup, no clue how to change the room nodes. I am rearranging the bedroom once again (due to more construction) and have made a new audio rack this week. So no more recent in room tests. I appreciate what you have noted too. I have found my Audyssey mic again and may retest this weekend or next week.

I also want to take a few spkrs into the parking lot here (only semi open space) to test a few spkrs sans room effects. If I do this, I will go from laptop output directly to a SS amp (?LT channel only), then to 1 speaker. Likely hold RS SPL meter about 3 ft of the ground, aimed straight up and maybe plugged directly into lappy to try to record output SPL of test tones. O/W I will have to record results all manually.I figure to do this about 9-12 ft from the spkr and to do 1 set straight on and another a few feet away (?15-30 degreesoff center). At least this might tell me that my spkrs are in spec. On a Lacala I also want to test an un-recapped AA network, my recapped AA, and one of the ALK Unis that I made. I would like to test the ALK trachorn too. Could also test each driver separately to check the effective roll offs from the passive networks. I would also like to test the WF-34 towers vs some new AV123 525s. Would also like to check my H Is and H IIs, and Academies. Of course all of this depends on weather, and it gets very hot and humid here over the 6 plus months of summer. Last weekend was sheer and utter misery, perfect for indoor stuff only.

I am getting some Altec 511s soon (902 drivers just arrived), but do not have a 2 way xover as yet. Is there a way to adjust a AA for 2 way use with a crossover at 500 Hz? Maybe later this fall I will get an active xover ?Behringer, dbx, or Ashley.

[DrWho]

http://www.hometheatershack.com/roomeq/

[nola]

Tried it last night with the RS SPL plugged into the lappy. I don't quite understand these curves. I used the RS SPL correction table. This portion went to just shy of 200 Hz. This chart and the ones above are different. This was automatic and fast!

WF-34s Lt/Rt and av123 gear C RL RR and RSW-15 sub. Onkyo 805, I think non Audyssey corrected. Sub xover at 80 controlled via the onkyo. My my my, have I got bass - and some room nodes.

Thanx so much for the link DrWho, whomever you may be

[DrWho]

If you step up to the Behringer ECM8000 ($50) and a mixer with phantom power (like the UB802 for $50), then you could do pretty reliable full range measurements.

One thing I'd like to throw out there (since you took so many measurements), is that even though the frequency response is all over the map in different locations of the room, most of what you see is the result of the same problem. In other words, just cuz you move to another spot doesn't mean that problem doesn't still exist. The waterfall plot might help you to see how the room is ringing. At spots where you've got nulls, you'll usually see it come back up in the tail of the reverb...we hear direct sound and indirect sound (reverb) differently, so this often causes spatial ambiguity in the music.

Also keep in mind that you can create boundary cancellation based on where you place the microphone:
http://www.peavey.com/support/technotes/soundsystems/boundarycancellation.cfm
I bring it up because the wavelength of 71Hz is about 16 feet (1132 / 71), so the 1/4 wavelength is around 4ft. I see a lot of dips at that frequency which can sometimes be accounted for a ceiling or floor reflection to the microphone. Putting the mic 4ft off the ground gets you both the floor and ceiling at the same frequency in an 8ft tall room. 4ft from the back wall just makes it even worse. If you ever get the chance, you can see it more clearly by going outside....measure in the middle of your driveway with nothing surrounding you and then measure again after pulling your car up so that you'll get a reflection to the mic. You'll see the addition of one dip if you do it right. Move the car closer and the dip will move up in frequency and then move it further away and it will go down in frequency. You can do the same thing by putting the speaker and microphone up into the air as well - and then the ground itself becomes the reflection path.