which frequencies?

**dimmie** · **06-24-06, 03:22 PM**

hey all,

I recently bought myself a BK monolith to acompany my kef eggs. And the time has come for me to do some room eq. Because I have quite some boomyness going on, and I want to get a BFD in the near future.

So I guess first thing's first, I need to know where the spikes are in the bass department, so I guess I'm gonna need to create a map of my room.

Can somebody tell me what frequencies to meassure?, is it smart to take every frequency ranging from say 20 hz. to 150 hz. which is the crossover I want to use. Because I've also heard somebody say to work with octaves.

Thanks,

dimitri

**Sonnie** · **06-24-06, 08:54 PM**

Hey dimmie and welcome to the Shack!

You might would consider using 80hz for your x-over.

As far as response measurements I would dive into to the Room EQ Wizard and take some sweep measurements from 20-200hz (which will actually measure 10-400hz) but then you can view what we all consider the normal 15-200hz and see what your response looks like.

Download and install REW... follow the HELP files step by step and then check out the REW Tips sticky thread in this forum here. That should give you a good start.

**dimmie** · **06-25-06, 02:31 AM**

Quote:

Sonnie wrote:

Hey dimmie and welcome to the Shack!

You might would consider using 80hz for your x-over.

As far as response measurements I would dive into to the Room EQ Wizard and take some sweep measurements from 20-200hz (which will actually measure 10-400hz) but then you can view what we all consider the normal 15-200hz and see what your response looks like.

Download and install REW... follow the HELP files step by step and then check out the REW Tips sticky thread in this forum here. That should give you a good start.

thx sonnie,

should I change it just for measurements?, because I like my sound a whole lot better at this x-over.

**brucek** · **06-25-06, 07:13 AM**

Quote:

should I change it just for measurements?, because I like my sound a whole lot better at this x-over.

No, measure with the crossover in plcae that you like. Measure with the sub only to equalize.

You also may find that once your sub is equalized, that a lower crossover may sound better. Any crossover higher than 80 can result in localization of the subwoofer itself, which many find objectionable....

brucek

**dimmie** · **06-25-06, 08:54 AM**

Quote:

brucek wrote:

No, measure with the crossover in plcae that you like. Measure with the sub only to equalize.

You also may find that once your sub is equalized, that a lower crossover may sound better. Any crossover higher than 80 can result in localization of the subwoofer itself, which many find objectionable....

brucek

You're right, I know. with this crossover I have to keep the sub right next to my front three speakers. sound from my sub is VERY directional now, but as long as I keep it close it's pretty good.

I'll get around to the REW and start learning then, and post any questions that may come up.

thanks guys,

dimitri

p.s. has the BFD been discontinued?

**brucek** · **06-25-06, 09:43 AM**

Quote:

p.s. has the BFD been discontinued?

It appears the 1124 was not available for a while, but that problem seems to have disappeared...

Quote:

sound from my sub is VERY directional now, but as long as I keep it close it's pretty good.

Yeah, you're losing stereo soundstage from your mains also.

brucek

**dimmie** · **06-25-06, 05:12 PM**

Ok....

Am I right when I think I have to connect my pc to my spl meter?....because I figured I could just take my spl meter, take meassurements at different frequencies, write them on a piece of paper and enter those values into a computerprogram which would give me a graph, telling me which frequencies I have to alter using my bfd?.

Or do I have to move my pc downstairs and have it actually take those meassurements physicly?.

I am setting up my home theatre, not a pc soundsystem.

**brucek** · **06-25-06, 05:53 PM**

Quote:

Am I right when I think I have to connect my pc to my spl meter?

Depends on the accuracy you want.

The use of tones and SPL meter combined with an excel chart are available for download here here. Download the excel chart that matches the type of meter you will use and then download some tones and you're ready to go..

The more advanced method that most everyone here uses now is with a PC and a program called Room EQ Wizard (REW) and is also available on the downloads page...

Take your pick.

brucek

**Otto** · **06-25-06, 08:16 PM**

Quote:

brucek wrote:

Take your pick.
brucek

Hi dimmie,

brucek is right when he says "take your pick." However, if I were in your shoes, I'd be happy to carry a PC and monitor (a CRT, even!) to the site. It's worth it.

Quote:

dimmie wrote:

I am setting up my home theatre, not a pc soundsystem.

Correct. This is much more important than setting up a pc soundsystem...

Go for it!

**dimmie** · **06-26-06, 02:39 PM**

Can somebody tell me what kind of cable I'll be needing for the spl to pc connection?. If I leave my pc where it is right now, I'll need about 10 meters of it. Is that gonna be expensive?.

I'll also have to check if I've got the right input on my mainboard as I don't have a seperate soundcard, but onboard audio on the mainboard. I've got a standard line in jack, will that be sufficient?.

How do I run the sweep?, do I burn it on cd?, and play it on my dvd player?. Or do I have to send a signal from my pc to my amp with yet another cable?.

questions...questions

Help would be appreciated

dimitri

**brucek** · **06-26-06, 02:58 PM**

Quote:

If I leave my pc where it is right now, I'll need about 10 meters of it. Is that gonna be expensive?.

That's really too long. You will pick up too much noise. Drag your PC over to the system and get a sensible length set of cables....

Here's a wiring diagram:

Quote:

I've got a standard line in jack, will that be sufficient?.

Yep.

Quote:

How do I run the sweep?

Read all of this. Your questions will all be answered..

brucek

**dimmie** · **06-26-06, 03:17 PM**

thanks again,

What are the benefits over the connections that you exampled, and the one which doesn't include the amp in the chain(as seen on the supplied help files).

I would like to keep it as simple as possible as I'm starting to break out in sweat after doing some reading. I understand that in the second schematic one also meassures main speaker response. but as I want to equalize the sub foremost, won't that be enough for the moment?.

I'm just trying to keep the start as simple as possible, because it all sounds pretty pro to me.

dimitri

tell me if I'm wrong of course

**brucek** · **06-26-06, 07:15 PM**

Quote:

What are the benefits over the connections that you exampled, and the one which doesn't include the amp in the chain

None. Actually you're at a bit of a disadvantage in that configuration because you don't have the bass management employed - which you want so you're able to track a standard crossover target in REW.

Then after you equalize with the sub only, you add the mains and check for phase problems and any negative interaction around the crossover frequency. You can't do this if you feed the BFD directly.

Quote:

because it all sounds pretty pro to me

No, it's easy.

brucek

**Sonnie** · **06-26-06, 11:54 PM**

Hey dimitri... it just looks intimidating because it's a lot of info. I thought the same thing and procrastinated using it for a while. I even think brucek procrastinated a little too in the beginning... not even close to being intimidating to him though. lol

We were somewhat encouraged by Bob (Malice) and brucek jumped in feet first and started to report back how easy it really was and actually I think he was having a lot of fun with it. I looked and thought... uh huh... that program is for the smart ones only.

I finally sat down and just took it one page at a time... HELP FILE! It really lays it out nicely when you do one step at a time. Once you've done it all once you'll look back and realize how easy it really is. It's really and truly not as bad as many people think.

Remember that we are here to help you if you run into a stumbling block.

I run from my soundcard output into my front inputs on my receiver so that I get the 80hz crossover included on my measurements. Not a necessity but an option and then you know how your x-over is effecting the response too.

**dimmie** · **06-27-06, 06:32 AM**

I'll have to get some cables then....

**JimP** · **06-27-06, 07:44 AM**

I would be very careful about the assumption that you want a flat response across your sub frequency range into the crossover and above. Yes, you do want to eliminate wild peaks and dips, but beyond that, adding some SPL to the full sub range and a bump at 35 dbs can do more to improve your total sound than adding more woofage.

**dimmie** · **06-27-06, 12:47 PM**

So, make the connection as stated in the example and let the amp(x-over) run along?.

I can measure first without the BFD right?, just to get a room response picture before I purchase the BFD?. It'll be some weeks before I can buy one.

**brucek** · **06-27-06, 01:04 PM**

Quote:

I can measure first without the BFD right?,

Yep..

**dimmie** · **06-27-06, 01:38 PM**

**dimmie** · **07-22-06, 02:32 PM**

hey guys,

I'm about to start measuring, but I was wondering if the line in/out plug which I use to connect my sub cable to my pc both have to be the double one showed in the schematic or that I can use two single ones?. I have to go shop for them this week, hope I can get them easy.

thank you

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