Home Theater Shack Forums
Epik Subwoofers manufactures world-leading high performance subwoofers for die-hard home theater and music enthusiasts who won't settle for anything less than the best.
PacParts, Inc.: Since 1969, PacParts has been supplying quality replacement parts & accessories from the most recognized manufacturers in the Consumer Electronics Industry.
GIK Acoustics: Home audio acoustics at its best... especially when you have help from the owners right here at the Shack!  Check out their very affordable acoustic panels!
Discount Merchant:  If you need a replacement bulb for your video device... look no further... save big!
ReliableHardware.com: A Reliable Source for Case, Cabinet and Acoustical Hardware!
Fi Audio: Infinitely amazing balanced high end musicality designed drivers!
SVSound: The Sound Authority in speaker and subwoofers as well as the astounding AS EQ1 Subwoofer Equalizer!
Elite Screens offers the finest in affordable projection screens.
Creative Sound Solutions: Loudspeaker kits and components for subwoofers, midwoofers, woofers and full range speakers!
Emotiva is your Home Theater Component Source for Audiophile Quality Home Theater Equipment at Factory Direct Prices
RAM Electronics: Audio, Video, Home Theater and Computer Cables.
Ultimate Home Entertainment: Providing home theater seating and accessories such as popcorn machines and signage... at very affordable prices!
Go Back   Home Theater Systems - Electronics and Forum - HomeTheaterShack > Equalization | Calibration > REW Forum
Room EQ WizardBFD Guide
Forgot Password?
Favorites Home Theater Links Donations Image Gallery

REW Forum

A little help needed with REW and house curves please.

Discuss A little help needed with REW and house curves please. in the Equalization | Calibration forum; A little help needed with REW and house curves please. Hello, I have spent the last couple days trying to get my head around how to use the REW, but ...


 Reply     Post New Thread
Views: 567 - Replies: 2  
Thread Tools
Old 06-04-07, 04:22 AM   #1
Shackster
Alias: Jamie
Loc: Waikerie, South Australia
User: #9297
Since: May 2007
Posts: 44
  wilsonj is online now  
A little help needed with REW and house curves please.


Hello,

I have spent the last couple days trying to get my head around how to use the REW, but I am still unsure about a few aspects.

My equipment
M-audio 24/96 USB soundcard
EC8000 mic
Behringer 802 mic power
DSP1124P
gereric digital SPL meter

Funny enough I have had this equipment for 2+years and never really got around to using it properly!

OK, so I have managed to calibrate my soundcard, checked leverls and entered in the cal file for the mic.

A question on the next step, checking levels. The REW notes say to increase the vol. until the meter reads 7db. Do they mean my digital SPL meter? C pr A??

Next question, weighting for SPL calibration. Should I have my SPL meter set to C or A. I assume A, as the REW notes say untick the C box if using a mic.....

SPL calibration procedure. I untick the C weighting box, so I assume I don't use C weighting on my digital SPL meter either?

I managed to take some measurements. Everything seemed to go ok here.

Question about the graph. Should I smooth out the freq curve or leave the tab set to "none" ?

Should I look to try and smooth out bumps greater than 3db?

Final questions relate to the house curve. I set up a house curve to give me 10db more at 20hz than at 80hz (0db). When I use this curve and take a reading my frequency plot is always lower than the target curve, so consequently there are no peaks to correct. I manually dragged the target down to where I liked it and worked from there. But this doesn't seem ideal, or correct to me.

I'm not sure I get the target level concept entirely...

Once finished I used my digital SPL meter to calibrate my processor sub output. But find it way under what it was. No problems I wind the level up to 75db like all other channels. Then when watching movies the sub is waaaay overpowering. It feels about 10db too loud.

I have tried to read as many posts here as I could before asking silly questions. Sorry if they have been covered before.

Thanks

Jamie


Forum Rules Reply With Quote
Alt Advertisement
Old 06-04-07, 07:39 AM   #2
Shack Administrator
Platinum Supporter
Alias: brucek
User: #6
Since: Apr 2006
Posts: 7,180
  brucek is online now    
Re: A little help needed with REW and house curves please.


Quote:
A question on the next step, checking levels. The REW notes say to increase the vol. until the meter reads 75db. Do they mean my digital SPL meter?
Increase the volume of your receiver (the soundcard feeds the CD or AUX input of the receiver) until your digital SPL meter reads 75dB at the listening position. Then you match the REW meter to that level to get a rough calibration between the two (do this by clicking the MIC/METER tab in the Settings routine and select Calibrate SPL).

Note, if you're using a ECM8000 and preamp, after you set the 75dB with the receiver and digital SPL meter, adjust the ECM8000 output and the input level control in REW to get a good input level, then don't touch the ECM8000 preamp level after that. Then Calibrate SPL in the REW program.

Quote:
Should I have my SPL meter set to C or A. I assume A, as the REW notes say untick the C box if using a mic.....
Meter to 'C' weight. The REW has 'C'-weight unticked because the meter calibration file is used in its place. The 'C'-weight of most meters isn't a correct curve down at low frequencies, so we substitute our own file.

Remember in your case, the only reason you're using the SPL meter is to get an initial calibration in the room of 75dB and to match the REW SPL meter to it. After that you use the ECM8000.

Quote:
Should I smooth out the freq curve or leave the tab set to "none" ?
Set smoothing to none. It's only used at higher frequencies where combing causes the graphs to be somewhat unreadable.

Quote:
When I use this curve and take a reading my frequency plot is always lower than the target curve, so consequently there are no peaks to correct. I manually dragged the target down to where I liked it and worked from there. But this doesn't seem ideal, or correct to me.
Attempting a house curve when your natural response is much lower than the target requires manual intervention. Sometimes it just ain't possible to get the curve you want, given the sub and the room.
Take your reading and then place your target at the spot you like and then let REW suggest filters. Then manually see what you can do. Keep in mind that gain is not advised.

Quote:
But find it way under what it was. No problems I wind the level up to 75db like all other channels.
Yeah, filtering lowers the level somewhat and to compensate you have to raise the sub amp a bit. That should be correct if it is balanced with the mains. Shows us a sub only and a sub+mains graph (using vertical scale of 45dB to 105dB and a horizontal scale of 15Hz to 200Hz).

brucek


Forum Rules Reply With Quote
Old 06-05-07, 04:03 AM   #3
Shackster
Alias: Jamie
Loc: Waikerie, South Australia
User: #9297
Since: May 2007
Posts: 44
  wilsonj is online now  
Re: A little help needed with REW and house curves please.


Hi Bruce,

Thanks for your replies. Looks like I have things working right now. I spent some time today with the mains also, playing with xovers in the lexicon. Now I think they integrate nicely with the sub.

Movies now sound more balanced with better bass extension. I can't believe I hadn't done this earlier!!

I'm off to setup Dad's system now.

Thanks again for your help, it was greatly appreciated.

Cheers
Jamie


Forum Rules Reply With Quote
 Reply     Post New Thread

« Home Theater Shack > Equalization | Calibration > REW Forum »

« Previous Thread   Next Thread »

Bookmarks
Thread Tools

Posting Rules
You may not post new threads... You may not post replies... You may not post attachments... You may not edit your posts

BB code is On... Smilies are On... [IMG] code is On... HTML is not allowed!




Parts Express: The #1 Internet source for all your DIY and electronics needs!

Ultimate Home Entertainment

This site is best viewed with a screen resolution of 1280 x 1024 or higher!

All times are GMT -5. The time now is 07:18 PM.



Powered by vBulletin
Copyright ©2000 - 2009, Jelsoft Enterprises Ltd.
Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.

Copyright ©2006 - 2009, Home Theater Shack, LLC.
John Mulcahy and Sonnie Parker - ALL RIGHTS RESERVED!



Projector Screens   AV Carts   Lectern   WhiteBoards   Audio Video   HDMI Cables   Multimedia   AV Blog
Massage Chairs   Wall Fountains   Bath Vanities   Electric Fireplaces   Bunk Beds
Dish Network     Dish Network deals




Sponsor/Vendor Ad Rates

Search Engine Friendly URLs by vBSEO 3.3.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331