Previous Thread
Next Thread
Print Thread
Rate Thread
Page 7 of 11 1 2 5 6 7 8 9 10 11
Re: Stupid Room Tricks
bridgman #406972 09/04/14 05:02 AM
Joined: Jul 2006
Posts: 12,077
Likes: 7
C
CV Offline
Founder, Axiom Upgrade Club
shareholder in the making
Offline
Founder, Axiom Upgrade Club
shareholder in the making
C
Joined: Jul 2006
Posts: 12,077
Likes: 7
I just wanted to say that I appreciate you sharing your experimenting with us all. Great thread.

Re: Stupid Room Tricks
bridgman #406973 09/04/14 05:15 AM
Joined: Aug 2004
Posts: 6,379
Likes: 7
axiomite
OP Offline
axiomite
Joined: Aug 2004
Posts: 6,379
Likes: 7
So after a brief "LFR" experiment (turning the M40's to face the wall -- doesn't work so well without a DSP) I moved the M2's back upstairs and put the M40's back on higher (~10.5") stands, toed in about 2/3 of the way towards the listener.

If I want really deep bass I can always bring one of the subs downstairs.

Last edited by bridgman; 09/04/14 05:16 AM.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: Stupid Room Tricks
bridgman #406990 09/04/14 04:02 PM
Joined: May 2002
Posts: 5,745
Likes: 17
axiomite
Offline
axiomite
Joined: May 2002
Posts: 5,745
Likes: 17
I'm going to need some spreadsheets and ppt presentation from you to pull all this together, you do realize that no?


"Those who preach the myths of audio are ignorant of truth."
Re: Stupid Room Tricks
bridgman #406992 09/04/14 04:16 PM
Joined: Aug 2004
Posts: 6,379
Likes: 7
axiomite
OP Offline
axiomite
Joined: Aug 2004
Posts: 6,379
Likes: 7
No worries -- I'll try to follow the usual corporate model of "if I don't know what I'm doing yet, dump everything I know into a long rambling powerpoint deck and hope people will think I'm making progress".

There's still some uneven bass response but so far I've only found one song that really shows it off -- Genesis' "Can-Utility and the Coastliners" from Foxtrot. Hopefully my RS sound level meter will surface from my brother-in-law's basement and give me a no-cost mic that I can use for some redneck room analysis.

Did you get a chance to look at your RS SPL meter and if so did it have an output jack ?


M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: Stupid Room Tricks
bridgman #406997 09/04/14 04:54 PM
Joined: May 2002
Posts: 5,745
Likes: 17
axiomite
Offline
axiomite
Joined: May 2002
Posts: 5,745
Likes: 17
Originally Posted By: bridgman

Did you get a chance to look at your RS SPL meter and if so did it have an output jack ?

I did check and yes it does have a RCA output jack.
Not exactly sure what i could feed that into.


"Those who preach the myths of audio are ignorant of truth."
Re: Stupid Room Tricks
bridgman #406999 09/04/14 06:47 PM
Joined: Aug 2004
Posts: 6,379
Likes: 7
axiomite
OP Offline
axiomite
Joined: Aug 2004
Posts: 6,379
Likes: 7
AFAIK it's a line-level output, which would go into the blue line input minijack on a typical sound card (pink is microphone input). At that point all you need is something like Room EQ Wizard (the "REW" everyone talks about) and you're ready to start making undecipherable graphs.

I found an online manual link which seems to match what I remember about my meter:

http://www.ko4bb.com/Manuals/08%29_Misc_...r_with_Mods.pdf


M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: Stupid Room Tricks
bridgman #407198 09/14/14 04:00 PM
Joined: Aug 2004
Posts: 6,379
Likes: 7
axiomite
OP Offline
axiomite
Joined: Aug 2004
Posts: 6,379
Likes: 7
Originally Posted By: bridgman
There's still some uneven bass response but so far I've only found one song that really shows it off -- Genesis' "Can-Utility and the Coastliners" from Foxtrot.

OK, I found more tracks that showed the uneven bass response frown

Experimented some more with speaker stand height and found that (a) I could lower the speakers a fair amount without noticeable change in frequency response as long as I toed the speakers in more to compensate, (b) with a 3.5" stand** (2 thicknesses of 2x6) the LF response was very even, to the point that some tracks which I had thought to have uneven bass on the recording (start of Pink Floyd's Meddle, for example) now showed even response.

This height seems to be right on the edge for FR and imaging (any lower is definitely a problem) but going any higher seems to start making the bass response uneven. The speakers are now toed in enough to almost point directly at me, so the visible side of the speaker appears to be less than a half-inch wide.

I did a bit of reading about floor bounce and AFAICS that seems to be essentially a first reflection thing but at low frequencies, ie the difference in path between direct and reflected LF results in some cancellations. The difference in path length seems to affect higher frequencies than the ones where I'm seeing changes, so guessing this has something to do with port and/or woofer height from the floor/wall/ceiling (although a few inches shouldn't make a big difference there either, so it's not clear what is happening).

** I guess if the stand is low enough I'm supposed to call it a plinth, wonder where the transition point is ?

Last edited by bridgman; 09/14/14 04:04 PM.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: Stupid Room Tricks
bridgman #407199 09/14/14 05:51 PM
Joined: Aug 2004
Posts: 6,379
Likes: 7
axiomite
OP Offline
axiomite
Joined: Aug 2004
Posts: 6,379
Likes: 7
Apart from the obvious conclusion that room and placement can make a huge difference in your listening enjoyment, I'm starting to believe that interaction with the room (ignoring how good the room is) explains another mystery that's always bothered me.

I have often seen a significant difference between reviewer comments about bass response and what the frequency response charts from an anechoic chamber show, even when reviewer and listening room are the same. It's not at all unusual for a speaker with smooth response down to ~40 Hz to be described as having weaker bass than a speaker which starts to roll off at ~70 Hz and is ~10dB down at 40 Hz (eg Soundstage reviews of PSB Image T45 vs Revel F12, where the T45 bass extension goes quite a bit deeper on the charts but the F12 is described as having deeper bass).

http://www.soundstage.com/revequip/psb_image_t45.htm
http://www.soundstage.com/revequip/revel_concerta_f12.htm

It's almost as if the reviewer only hears the bass from the drivers and not from the port(s), which doesn't seem to make sense unless ports and drivers are sufficiently far apart that they interact differently with the room... although there's the obvious argument that having drivers & ports separated is good because it can reduce the impact of room reinforcement by dividing the bass energy across multiple points each with a slightly different room response.

I don't remember worrying about all this stuff when I was building speakers... but back then we had just learned that restaurants were feeding "french fry smell" into the air and suspected that end audio stores might be using some kind of mild hallucinogenic in the HVAC system to make their systems sound so different from ours.

Last edited by bridgman; 09/14/14 06:30 PM.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: Stupid Room Tricks
bridgman #407298 09/18/14 02:26 AM
Joined: Aug 2004
Posts: 6,379
Likes: 7
axiomite
OP Offline
axiomite
Joined: Aug 2004
Posts: 6,379
Likes: 7
OK, that was interesting. Now that the room is finally beaten into shape I figured the next step would be to roll some different speakers through it. I figured that Magneplanar 1.6 or 1.7 would be the next step (I really liked the Quad ELS's I had during my mis-spent youth) but I ran across a pair of B-stock Ascend Sierra-1 speakers and ordered them. One of the reasons for trying Sierra's was that the most virulent Axiom haters (the ones who spit when they post) usually said nice things about Ascend speakers, so I figured I should own a pair of Ascends as well as my Axiom farm.

So... after disappearing from DHL's computers for a couple of days they finally showed up at my place. Executive summary is that I really like them, and they sound surprisingly different from my M40's, but the difference is a mix of "better" and "less better".

The M60s, and to a lesser extent the M40s, have an awesome clarity that's hard to explain without listening to them. You can pick apart different instruments, and there's almost a "clinical" aspect to the sound. Example is No Doubt's "Hella Good" -- with electric bass and bass synth both happening in the intro, normally it's hard to tell them apart but with the Axioms it's totally obvious that there are two different instruments at different positions in the soundstage. I haven't found the CD yet (I have a 200 CD changer and have to write down numbers for each CD) but you get the idea. The Sierra 1s don't have that level of detail, although the NRT (Neodymium Ring Tweeter or something like that) option apparently gives you that.

Anyways, I think the M40s play deep bass more clearly than the Sierra's, but the Sierras do something in the mid-bass that is more open than anything I've heard on M40s or M60s (both ti vintage). The newer Axioms have different crossovers and different frequency response, so I think I need to sync up with current sound rather than 10 year old sound.

Current thinking is that I want to combine Axiom M60ti sound from maybe 1 KHz up, Sierra sound from a couple of hundred Hz to 1 KHz, and something I haven't owned for years from 30 Hz up to a couple of hundred Hz. Looking at the different curves between regular and HP speakers there's a good chance that the HP woofers & associated cabinet/crossover changes do just that.

Seems like I need to carve out time for a trip to Dwight.

Anyways, between M40s, M60s and Sierra-1s I'm really enjoying my record collection smile

Major things to investigate so far :

1. Grand piano sounds more realistic on the Sierra's, which is a surprise -- I expected the Sierras to be different around the crossover freq but not so much at other frequencies

2. My primary test recording for ~30 years has been the first track off Triumvirat's "Old Lives Die Hard". Still not sure why -- it's a pretty bland recording -- but there's a mix of bass drum and bass guitar that seems to be a pretty good leading indicator for how I'll like the sound of the speaker.

Best playback so far was the old PSB "acoustic feedback" servo speaker using a Philips DeForest 8" woofer with a servo coil, followed by my old 3-way KEF DIY speakers. The Sierra's sounded better than the M40s but will try them against the M60s on the weekend.

The difficult thing about comparing these speakers is that the Sierras are M3 class in terms of ability to play loudly, but M40/M50 class in terms of bass response. Anyways, they're interesting.

Last edited by bridgman; 09/18/14 03:05 AM.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: Stupid Room Tricks
bridgman #407301 09/18/14 10:16 AM
Joined: Sep 2004
Posts: 11,458
shareholder in the making
Offline
shareholder in the making
Joined: Sep 2004
Posts: 11,458
John, there's nothing meaningful I can add to your thread but wanted to let you know that I enjoy reading about your journey.


::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::
Page 7 of 11 1 2 5 6 7 8 9 10 11

Moderated by  alan, Amie, Andrew, axiomadmin, Brent, Debbie, Ian, Jc 

Link Copied to Clipboard

Need Help Graphic

Forum Statistics
Forums16
Topics24,940
Posts442,457
Members15,616
Most Online2,082
Jan 22nd, 2020
Top Posters
Ken.C 18,044
pmbuko 16,441
SirQuack 13,840
CV 12,077
MarkSJohnson 11,458
Who's Online Now
0 members (), 563 guests, and 1 robot.
Key: Admin, Global Mod, Mod
Newsletter Signup
Powered by UBB.threads™ PHP Forum Software 7.7.4