Yet another cost effective main speakers build

[AllenB]

I thought so. We don't get too many RF guys here in speakers

 

[JRiv]

Hi again.

I've took all the sofa pillows and foams and added them at the sides of the speakers and front bottom to minimize some of the reflections.

Then take few measurements of the speakers with the port open and closed on axis at 3 feet, also added a little PEQ in a dip this time at about ~181Hz with +10db with a Q of 6 to improved it just a bit, so I expect to improve the overall response a bit better over time after learning some more about.

Regards

 

[AllenB]

Then when they aren't enough, out come the quilts and blankets. Then your significant other calls out 'what happened', corrupting the measurement you were just taking.

a little PEQ in a dip this time at about ~181Hz with +10db with a Q of 6

That's quite a hit. Probably a room mode. It's worth considering that when you have opposing forces (sound combining from reflections, similar in level and more out of phase than in) that are conspiring towards a null, EQing becomes like trying to fill an abyss, I'm sure you're familiar with the concept. The room mode will be position specific. Move around a bit and you may find there's too much sound at that frequency. You may find it worthwhile to try moving your speaker around the room.

 

[JRiv]

Hi, you are certainly right about quilts and the blankets.
About the room mode again right, sometimes we just brute-force EQ just to try to quick fix a problem, but many times is quite the contrary.

I've moved the box to take measurements, and the dips and valleys moved in frequency at the lower end, and looked somewhat worse just like on my previous attempts, apparently when they placed in the floor at 8.5" clearance from the back wall, and with the bed at front of them(about 4'), the bed acts like a bass trap slightly improving the low end of the measurements.

Unfortunately this small bedroom is a bit bloated with some stuff around I need to move to another room permanently to gain some space, then will take some more measurements after the cleanup with the sub engaged to see how the overall response looks like, this hobby is getting entertaining.

Regards

 

[AllenB]

A sub, excellent. This can be the key to dealing with room modes.

 

[djn]

Nice build J. All things considered, that graph looks good. How do they sound? Did you do any measurements outside? Room interaction could be causing those nulls and peaks.

 

[JRiv]

Nice build J. All things considered, that graph looks good. How do they sound? Did you do any measurements outside? Room interaction could be causing those nulls and peaks.

Hi djn, thanks for the input, they do sound very nice and have a nice low-end down to about 40ish Hz considering the specs of the mid/woofer used in the project, but indeed there is the room gain factors to be considered as well as they are low tuned on purpose.

I also considering to take some measurements at the outside too, an open garage-like area, but there is still a ceiling there at 8', unfortunately we have very low space area at the back of the house in this old urbanization, but I will try get cleaner response curves.

Regards

 

[JRiv]

Hi, while this grilles are certainly ugly looking in home environments but since Pro audio mid/woofers are fragile by nature(paper cone), wanted to protect them temporarily when I'm not using the speakers.

So I had the idea of using some 10x3mm strong neodymium magnets and reuse some 10" metal grilles I had lying around for a temporal solution, since the magnets are strong enough I only put magnets in four even locations that provides enough pull pressure to hold them.

Note that this mid/woofers I've used had a steel basket plus I've used black-oxide steel screws too, but for cast-aluminum drivers the screws should be steel, however some alloys with enough ferromagnetic metals may work.

Now I'm just looking for a better looking 10" grill to play with, or either a thin wooden or metal ring with grill cloth, or even just a standard square speaker grill cloth covering the horn and the woofer if diy.

P.S. Sorry for the images quality due poor light in the room.

Regards