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Post by Boomzilla on Jul 27, 2020 10:17:12 GMT -5
OK - This will be the last of the Mohicans... Part 1 of this Experiment shown HEREPart 2 of this Experiment shown HEREI unstacked the T2s, and set them up in phase with in "front-firing" and "rear-firing" configuration. I initially set the rears parallel to the back wall, then toed them inward a bit, and then toed them inward a lot. The latter sounded best. After aligning the speakers, I set up the subwoofers outboard of the speakers. The measurements below are combined R+L sweeps of the setup in the shown configuration. FREQUENCY RESPONSE: DISTORTION: WATERFALL: IMPULSE RESPONSE: RT-60 DECAY: I note that the subwoofers absolutely FIXED the bass suckout. Chew on THAT, mini monitor lovers! LOL And I guess that I'd better update the equipment list to clearly show what was in play here: Music library on WD external USB-3 HDD (4 TB size) Roon software on a Mac Mini using an iPad for control USB connection to a Black Ice Audio tube DAC RCA connectors to the Audio-gd HE-1 SS preamplifier XLR balanced connectors to an Emotiva XLR splitter Second XLR splitter cable to both channels of two Ashly FTX-2001, Series 3 "pro" amplifiers 6' 10AWG cables to each speaker (one amplifier channel per 4-Ohm speaker - Speakers run full-range) XLR from Emotiva splitter to each Airmotiv S15 subwoofer with subwoofer plate amp set to roll off at 60 Hz. Note also that all measurements are sans ANY equalization or DSP. I believe that the sub equalizers (the Dayton DSP-LF units) can smooth the bass significantly more. Boomzilla OK - Having spent the morning listening to this setup here are my notes: - The soundstaging capabilities of this setup are just plain amazing. You not only hear the voice(s) from the center of the soundstage, but you hear the ambience around them! Were they in a sound booth? No ambience. Were they in a reverberant space? You can hear plainly the size of the venue.
- Bass slam galore! With electronic music (that I particularly like on occasion), the body effects of the low bass are THERE (and you don't even need high volumes). Even with acoustic music (Jennifer Warnes' "Way Way Down Deep") the kick drum kicks your diaphragm.
- Not the utmost in soundstage width, but deep, deep, deep instead.
- Some of the smoothest frequency responses I've heard in my room
- For the amazing soundstage, you do give up a bit of dynamics. Is this tolerable? Time will tell...
- This is revealing pretty vividly that the T2 speakers are NOT phase-coherent designs. And I wish they were...
So is this (to steal a phrase from the Home & Garden channel) my "forever house?" If you know me, I think you already know the answer to this question! LOL
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Post by garbulky on Jul 27, 2020 14:11:57 GMT -5
*Ahem* may I reccomend another look at a second set of PA-1's? If you are talking about revealing the ambient sounds and the size of the venue, that's what I thought was so remarkable about the PA-1's did. They had very fast dynamics and were able to reveal ambient sounds. As for soundstage width, I think that will come with some more experimentation!
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Post by garbulky on Jul 27, 2020 14:13:55 GMT -5
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Post by garbulky on Jul 27, 2020 14:51:08 GMT -5
You also have one more choice. Place them on their sides on top of each subwoofer. Have the tweeters on each stack flipped. So a tweeter from the top speaker is above the woofer of the second.
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klinemj
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Post by klinemj on Jul 27, 2020 16:08:21 GMT -5
Did you do the sweeps with the T2's in the best configuration but without the sub? The final T2 configuration + the subs looks a lot better - would love to hear the difference, but the data shows it certainly filled the "Energy suck" of your room.
Mark
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Post by Boomzilla on Jul 27, 2020 21:09:49 GMT -5
Did you do the sweeps with the T2's in the best configuration but without the sub? The final T2 configuration + the subs looks a lot better - would love to hear the difference, but the data shows it certainly filled the "Energy suck" of your room. Mark I did not. Why? Because the "best configuration" is still in flux. Tomorrow, I'm trying the "effects T2 pair" toed outward significantly with the main pair moved closer together & toed in.
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Post by Boomzilla on Jul 28, 2020 4:27:01 GMT -5
You also have one more choice. Place them on their sides on top of each subwoofer. Have the tweeters on each stack flipped. So a tweeter from the top speaker is above the woofer of the second. Alas, this is not feasible. Why? The Sanus Euro stands have a weight limit below the combined weight of the S15 subs and two pairs of T2s. Experience has shown me that if I exceed the stands' weight limit, the support tubing on the bottom deforms and the whole rack tilts. I almost dumped a whole review group of McIntosh gear on the floor one time because the stand was deforming! The only good way to avoid deformation is to eliminate the support tubing base entirely, and to use plate casters, screwed directly into the bottom wooden shelf. I've done that with my main "double wide" equipment rack, but have not yet done it with any of the single-width racks. I can, however, as klinemj has suggested, place the two towers side-by-side, and may do so soon. While they're close like that, it may also be time to try wiring the towers in series and bridging the Ashly amplifiers. KeithL and/or DYohn and/or leonski - What happens to phase angle when identical speakers are daisy-chained in series? Thanks - Boom
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Post by garbulky on Jul 28, 2020 8:37:07 GMT -5
Perhaps put the subs on the floor to avoid damaging the stands? You probably elevated the subs to for better sound though....
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DYohn
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Post by DYohn on Jul 28, 2020 9:10:25 GMT -5
What happens when you place loudspeaker systems in series is 1) you double the net impedance loading the amplifier. This has the effects of reducing the output dbSPL for any given volume setting, and of reducing the total damping factor of the system significantly. 2) you introduce a time delay phase shift in one loudspeaker relative to the other as the crossovers are now in series and affecting each other. This may or may not be audible and depending on system placement might cancel out. 3) anytime you introduce multiple systems reproducing the same signal you introduce unpredictable time-domain cancellations in the listening space due to lobing. Again the degree to which this is audible (or even detrimental) varies depending on speaker placement and room geometry.
Try it. What have you got to lose?
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Post by Boomzilla on Jul 28, 2020 9:35:56 GMT -5
Perhaps put the subs on the floor to avoid damaging the stands? You probably elevated the subs to for better sound though.... Elevation WAS instrumental in making the subs "boom less."
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robs
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Post by robs on Jul 28, 2020 13:28:28 GMT -5
I never was able to play those T2s at moderate volume due to living in an apartment, but having a Schiit Vidar hooked up to them (and later a second to have them in monoblock configuration) I can imagine how insane the bass slam and authority would be. In a bigger room and having the ability to crank them would be nuts. And with subs? How are you not making an earthquake LOL.
I thought the sound-stage depth with only a pair was very good.
My issues were I didn't like how sharp the AMT tweeters were and the small sweetspot. The lack of phase coherency you mentioned was another problem.
Interesting experiments nevertheless.
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Post by Boomzilla on Jul 28, 2020 13:41:38 GMT -5
I'm needing subs because my room is so "lossy" in the bass region. All four corners are vented to other areas and there's little standing wave action.
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klinemj
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Post by klinemj on Jul 28, 2020 15:41:32 GMT -5
anytime you introduce multiple systems reproducing the same signal you introduce unpredictable time-domain cancellations in the listening space due to lobing. Again the degree to which this is audible (or even detrimental) varies depending on speaker placement and room geometry. Suddenly I'm flashing back to 1979 when Steve Taylor and I removed the back seat from his '68 Chevelle (including the metal behind the seat) and he hung up a bunch of speakers in its place (all wired in series). It produced an interest effect...well, either that did it, or perhaps those "cigarettes" we were smoking as we cruised around impacted our perception. Mark
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DYohn
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Post by DYohn on Jul 28, 2020 16:45:48 GMT -5
anytime you introduce multiple systems reproducing the same signal you introduce unpredictable time-domain cancellations in the listening space due to lobing. Again the degree to which this is audible (or even detrimental) varies depending on speaker placement and room geometry. Suddenly I'm flashing back to 1979 when Steve Taylor and I removed the back seat from his '68 Chevelle (including the metal behind the seat) and he hung up a bunch of speakers in its place (all wired in series). It produced an interest effect...well, either that did it, or perhaps those "cigarettes" we were smoking as we cruised around impacted our perception. Mark I bet it was "amazing, man."
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klinemj
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Post by klinemj on Jul 28, 2020 18:42:36 GMT -5
Suddenly I'm flashing back to 1979 when Steve Taylor and I removed the back seat from his '68 Chevelle (including the metal behind the seat) and he hung up a bunch of speakers in its place (all wired in series). It produced an interest effect...well, either that did it, or perhaps those "cigarettes" we were smoking as we cruised around impacted our perception. Mark I bet it was "amazing, man." If I recall correctly, and knowing me and Steve, I think it was more like "duuuuuuuuuuddddde....this tooooooootallly rocks". But, you didn't hear that from me. Early AC/DC and Black Sabbath were likely involved. OK...they were involved. Mark
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Post by Boomzilla on Jul 29, 2020 13:49:50 GMT -5
OK - I think I found the position for the dual T2s. The "main pair" is slightly closer together and slightly toed in. The "effects pair" is toed OUT at about a 45-degree angle. The Ashly amps are running two speakers in series, and the two amplifier channels are bridged for each amplifier (1,350 watts into the 5 ohm load). The image is both wide and deep. Good articulation and dimensionality. Subs are active and the bass is pretty flat with only a slight peak at about 50 Hz. Dynamics are excellent.
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Post by garbulky on Jul 29, 2020 13:54:45 GMT -5
Very interesting placement. You have me wondering how it would sound. It's sort of like a "wrap around" effect for the speakers on the outer side. Must be giving you a more omnidirectional feel to it.
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Post by Boomzilla on Jul 29, 2020 14:51:21 GMT -5
Very interesting placement. You have me wondering how it would sound. It's sort of like a "wrap around" effect for the speakers on the outer side. Must be giving you a more omnidirectional feel to it. Dependent on the material being played. Some stuff sounds like it's coming from behind you. Other stuff clumps near the center. But even the center image stuff makes up for its lack of width by being VERY deep.
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Post by Boomzilla on Jul 30, 2020 1:55:47 GMT -5
And an excellent email was received with phase angle information for series speakers:
Glenn 1) I have never seen a speaker with internal drivers in series. I have seen some simple series crossover circuits in the past but not for a long time. They tended to be low order. Your assumption that the connection at the middle of the speakers is Vin/2 assumes the impedances of the two speakers match. They do not as a result of manufacturing tolerance. You also have to remember the graph you show below is a small signal (less than a watt) linear representation. As the voltage drive does up the speakers suspension and spider change compliance at the limits as does the impedance of the motor as the coil starts to get near the end of the gap. Good enough for sound reinforcement. I also suspect the rule is parallel for two then next two series. Allows the 4 speakers to average the errors. You need a speaker engineer to answer the question of what disadvantages occur when put identical speakers in series when all the issues are considered. 2) It is not the question you asked so let us move on to what you did ask. Z = magnitude (f )> phase angle (f ) where f is a given frequency. Call the magnitude at f MAG and phase of f PHA It is now time for some junior high math so I can convert magnitude and phase into real and imaginary Re = Magnitude cos (phase) Im = Magnitude sin (phase) Let us define them for one speaker as: REL =MAG cos PHA IMG = MAG sin PHA Since you have two identical blocks in series we double these: REL (identical series) = 2REL (individual) IMG (identical series) = 2IMG Now we have to go back. The magnitude is the square root of the square of the real and imaginary lets skip that. Trust me it is coming out 2 MAG The phase is tan –1 (Re / Im) =tan-1 (2REL/2IMG) = tan –1 (REL/IMG) So we have no change in phase.
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Post by mgbpuff on Jul 30, 2020 5:36:07 GMT -5
So the result is the same as I said. Two new things have been pointed out. 1)The speaker components have a tolerance so they are unlikely to be identical, but I do not think that would cause a perceptible difference. 2) DYohn pointed out that the damping factor would be lowered significantly. This is probably the single greatest difference than all other factors.
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