HarleyMo Posted September 3, 2006 Share Posted September 3, 2006 This is a curve from my diy khorns. Since Im not much of an audio engineer, Im wondering how bad this really is. I know there can be alot of things that factor into the curve. Room size, shape, sound deadening etc. My room is not the best, and I know it, will be moving them to the basement when I finish it. Walls are pretty bare so lots of reflections Im sure. The measurements were taken with pink noice at a flat 70db, with a strykes basszone test cd and a rat shack analog meter. The meter was at the listening position approx 8 feet in front of the speakers which are about 15' apart. Corrections have been applied. Thanks for your guys input. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted September 3, 2006 Share Posted September 3, 2006 What would concern me is the "sag" between about 800 to 2.5KHZ. The bass region is so room dependent as to be an insignificant region in an analysis of this type.as long as it sounds "right". Any necessary corrections can be made when the horns are in their permanent location. What driver/horn squaker combo are you using? Rick Quote Link to comment Share on other sites More sharing options...
HarleyMo Posted September 3, 2006 Author Share Posted September 3, 2006 k55-V spring loaded terminals. K400 horn. Crossover is an ALK. They actually sound Very Good. I wanted to do the curve just for the heck of it, not cause they were sounding bad. Thanks Harley Quote Link to comment Share on other sites More sharing options...
DrWho Posted September 3, 2006 Share Posted September 3, 2006 Hmmm, even for the ratshack meter that's a bit extreme... The bass bin looks a bit hot, but it's probably from standing waves in the room. What are the dimensions of your room and is it sealed well or open to the rest of the house? And what test tones were you running on the CD? One thing you might try is to redo the test, but move the SPL meter around and take the largest measurement within a reasonable radius around the listening position. At the higher frequencies you'll notice that moving as much as an inch or two will have dramatic swings (which you can also hear yourself when you move your head around). This is all the result of standing waves - so moving the meter around helps alleviate this issue. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted September 3, 2006 Share Posted September 3, 2006 some of it doesn't make sense.... for a KH bin gotta be .. measurement technique, and room ..... Quote Link to comment Share on other sites More sharing options...
HarleyMo Posted September 3, 2006 Author Share Posted September 3, 2006 Well, I know the room sucks. Its very open, opens up to the kitchen eating area in back and to the left opens to entry way to house, bay window on right. Lots of relections Im sure. Where is the best place to put the meter to get the most accurate reading? Quote Link to comment Share on other sites More sharing options...
DrWho Posted September 3, 2006 Share Posted September 3, 2006 move the SPL meter around and take the largest measurement within a reasonable radius around the listening position The best place to measure is many locations at once - like within arm's reach. No matter what, constant test tones are going to stabilize into standing waves inside the room. By taking the loudest measurement from moving the mic around you are essentially measuring the peaks of all the standing waves. If the speaker is 3dB less at 800Hz than 500Hz, then the peaks should show the same difference (a fairly accurate assumption). The reason you need to move the mic around is because the peaks for 500Hz and 800Hz occur at different positions in the room (because their wavelengths are different). Quote Link to comment Share on other sites More sharing options...
HarleyMo Posted September 3, 2006 Author Share Posted September 3, 2006 Ok, I retested to fix the "technique" problem. I placed the meter on a tripod away from furniture and approx tweeter highth. This is what I got. Sorry Dr Who, I did this before I read your suggestion. Ill do that next. Quote Link to comment Share on other sites More sharing options...
rcarlton Posted September 3, 2006 Share Posted September 3, 2006 Here is a reading using the RS SPL meter of my K-Horn. Used corrections. The meter is not very good after 10KHz. Quote Link to comment Share on other sites More sharing options...
rcarlton Posted September 3, 2006 Share Posted September 3, 2006 K-horn reading using a microphone. Ignore the lower frequencies, used a subwoofer. Note somewhat flatter response at higher frequencies. Quote Link to comment Share on other sites More sharing options...
rcarlton Posted September 3, 2006 Share Posted September 3, 2006 Home Theater Shack has some guidelines for sharing graphs from REW that work well. Quote Link to comment Share on other sites More sharing options...
jwc Posted September 4, 2006 Share Posted September 4, 2006 The response between 50-80Hz is consistently low. Is there a way for you to EQ a little? I have found that I like for that range to be very prominent for good-quick thumping. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted September 4, 2006 Share Posted September 4, 2006 Harley that secong graph and Ron's mic graph are more like what I would expect from a Khorn with room gain in the bass region. In yours Harley, the return at 9KHz of the K55V is evident. A P-trap would help there. How are the horns coupled in the corner? Loose coupling could explain the drop off between 200-400Hz. Rick Quote Link to comment Share on other sites More sharing options...
HarleyMo Posted September 5, 2006 Author Share Posted September 5, 2006 Well, Ive tried to get them into the corners as tight as possible and have some foam tube insulation on the tailboard to try to help seal them. Ill check that and see if I can get them to seal better. As for the ptrap, Ive heard of them Ill search the forum and do some research. Thanks Harley Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted September 5, 2006 Share Posted September 5, 2006 The wavelengths at 500-200Hz are 2 - 5 ft long. I agree about snugging the cabinets ito the corners, but that drop off could also be the distance of the mic to the floor (or ceiling). Your measurements using long duration signals will include large dose of room effects. If you place a blanket or pillow on the floor, does the dip attenuate? Good luck and I think you are taking the right approach by employing some measurements (although they are not always straight forward). -Tom Quote Link to comment Share on other sites More sharing options...
HarleyMo Posted September 5, 2006 Author Share Posted September 5, 2006 Well, like I said earlier in the thread. The speakers sound great, I am very happy with what I hear coming out of them and how they turned out cosmetically. I had access to the sound meter and thought I would measure them to see how they compared to factory speakers. The meter during the second measurement was on a tripod 4 foot above the carpeted floor and centered approx 8 feet in front of the speakers. The room has a 12foot vaulted cealing. Im sure the dip is room related. Quote Link to comment Share on other sites More sharing options...
rcarlton Posted September 5, 2006 Share Posted September 5, 2006 It might be a good idea to put the meter right at your listening position, at the same height as your ears. How does it look now? That is the position you want to tune the room with acoustic treatments. Quote Link to comment Share on other sites More sharing options...
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