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Loudspeaker EQ |
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8960 |
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Yes I agree Andrew. I think I wrote on the forum about my past efforts measuring with REW to generate EQ solutions for an old Behringer digital unit I pressed into service to feed my subs when I had the GX100's at the front. I had to get the MIDI cables out!
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Jon
Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
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Drewan77
Senior Member Joined: 25 May 2013 Location: Chester,England Status: Offline Points: 1544 |
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If you have a mic to measure and can set time delays on the sub (example below: main speakers +2 subs), it does make a big difference Jon...
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Older than I once was, younger than I'll be
............................. Andrew |
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8960 |
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In the end I kept the HF and MF switching apart. on midrange I went for 0dB (stock wiring), +1dB (10R in parallel), and +1.8dB (4R7 in parallel).I have also been having a first stab at blending my big REL subwoofer in with the GX300's. Their Fb is about 32 Hertz so they go quite low to start with. Their reflex design has a faster roll-off, typically 24dB/octave so blending my main subwoofer will be interesting. When the reflex port is plugged on each box plugged they are closed boxes with a Qtc of about 0.7 and Fc=58 Hertz, handy because their rolloff is just under 12dB/octave which is the slope of the REL's low pas filter. So it should be easier to blend.
I soldered up a high level cable for the REL, spades for speaker terminals and Speakon to go into the Q400's socket. Then followed the usual set up procedure: start with sub crossover and level to high, switch phase from 0 to 180 to find which setting is loudest. In theory I would set the sub's LPF on the speaker's -6dB frequency (about 42 for closed box, 32 for reflex), but it's a relatively small listening room of 40 m3. My conclusion this time was I preferred the GX300's alone! |
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Jon
Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8960 |
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Well I have identified three settings that I like enough to hard wire them into a three way switch:
Full HF plus the 4R7 and 3R3 in parallel so about 2.5 dB middle boost compared to stick - "detail excavator" HF on -2dB, no mid-boost - "comfy slippers" HF on -2dB, 10R and 3R3 in parallel for about 1dB mid-boost - "balanced when loud" |
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Jon
Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8960 |
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Incidentally I worked out that the drivers' efficiency bandwidth Product EBP was about 90 so close to the threshold between suitability for closed box and for ported box. The box volume Vb and two speakers' compliance Vas and Qts gave me Qtc of 0.70. So with the port plugs in I have a really good alignment for transients and slow bass rolloff. With the ports open I have plenty of low frequency oomph in my listening room.
The idea of trying midrange boost came from the way the sound I heard changed as the volume is turned up. My speakers have a slight bass boost and rising treble which works well at moderate levels but less so if I am listening to music loudly when I notice the extremes more. I concluded it was probably due to the equal loudness contours (showing low and high frequencies are perceived as quieter at lower sound pressure levels than the middle range of sound) and I think background noise inside and outside the house is a factor too. When doing these comparisons I also try switching one speaker only and listening to the impact on the soundstage. Unsurprisingly the 10 ohm had limited effect on positioning left to right where the 6.8, 4.7 and 2.2 ohm resistors spread/smeared the positioning of voices (overlapping the bass to mid crossover) and guitars/strings (mid and treble). Just an experiment at the moment. However I think I will probably be changing the switch I put in for the HF cut to a double pole unit so I can include a midrange option. I will do some more listening first! |
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Jon
Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8960 |
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Some time ago I made a cheap test rig so my copy of REW 5 could measure the Thiele-Small parameters of the drivers in my GX300 speakers and I could consider the alignment used. Yes it is BB4 and Fb = 32 Hz if you are interested.
This weekend I got round to exploring an option I considered back then. It was to measure and compare the LF impedance curves of the two enclosures. I then matched the two pairs of woofers to get the reflex/speaker alignments as close as possible in the two cabinets. They now have virtually the same impedance peaks and same Fb. The effect is probably limited to a slight difference in rolloff but they are now very close in their sub bass response. I'd be lying if I said I could hear it! |
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Jon
Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
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Ash
Senior Member Joined: 18 Mar 2013 Location: Dorset Status: Offline Points: 4334 |
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I have two pairs of Alpair 12PW that I can use to assist my single pair of 12P below 100Hz. This is so I don't have to use a conventional box to get really low bass in the nearfield. Don't yet know much about crossover designs but won't apply any crossover to the 12P; shall just shallow-slope filter the 12PW so they produce nothing above 100-150Hz. As bass frequencies are more omnidirectional, hopefully shouldn't get any lobing problems with two adjacent 12PW. If I do, I'll just use one and build a partial box for it. Will be able to level control the one or two 12PW using a second Proprius pair.
Edited by Ash - 20 Sep 2016 at 8:48pm |
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