GR or Adire? (1 Viewer)

[Dan Wesnor]

Rumbly = lack of definition in the lowest octave. The woofer doesn't seem to stop moving quickly enough. The texture you talk about is actually up around 100-200Hz.

 

[Michael R Price]

OK, so it's a problem inherent in the driver that I can't fix? Darn...

 

[Greg Monfort]

>Do you think something like blackhole 5 could be put in the Adire kit to get rid of the cabinet resonance in the bass?

>There's a rumbly sound? Do you mean some sort of harmonic distortion, or cabinet resonance, or a frequency response problem, or something? If such a thing exists, I'd like to fix it if possible in my speakers. I have noticed the Kit281s bring out a "texture" in the bass that I haven't heard in my limited experience, but I thought that was good, not a defect.

>OK, so it's a problem inherent in the driver that I can't fix? Darn...
====
Not so! The driver itself is overdamped (Qts = < 0.5), so this is a cab and/or alignment issue. If you look at Adire's FR plot for these you'll see that they chose an underdamped alignment (tilted up LF response). This causes what I consider to be excessive 'ringing' (degradation of transient/impule response) in the LF's harmonics, and I imagine what folks are hearing, especially since the room more often than not accentuates it.

Tuning the cab lower/increasing stuffing will help somewhat in some ways hurt in others due to the excessively long vent, but making a larger, lower tuned cab will correct it, and while it will sound 'tighter', it probably won't sound as tonally balanced overall unless the room helps enough, possibly requiring some (more?) baffle step compensation which I imagine will affect the XO ckt. design :frowning:

Internally, the 'x' frame bracing causes mids/HF standing waves so damping their surfaces might audibly help. Also, in lieu of tuning it lower with the vent you can apply one or more layers of fiberglass or polyfil sheeting over the large holes in the bracing to somewhat aperiodically damp the cab/vent's pipe action.

Out of curiosity I modeled Adire's vented version and not surprisingly the results mimicked Adire's measured response and also showed the affect on the upper harmonics due to the woofers being placed near one end of the pipe.

Maintaining the same height/woofer positioning, but with larger Vas (4.66ft^3)/lower Fb (~31Hz) shows good pipe gain/flatter response down to 40Hz where it smoothly rolls off to a low 20s F10, and of course the phasing issues due to the woofer placement. My preferred layout is a bit shorter though, with the woofers ~centered down the cab to better utilize the pipe's action, reinforcing higher up the FR with the same LF response, though with fewer, more benign phasing issues, ergo less stuffing required.

How audible the differences are between a 'fatter version of Adire's design and mine is to a great extent room/person dependent, and more stuffing in the Adire layout appears to offset this, but either one should perform better overall. This isn't to trash Adire's design, all manufacturers stay 'under the gun' to keep size down and provide as much 'bang for the buck' as they can within pretty restrictive limits, and considering how many folks like a 'bouncy' bottom end, their design appears to balance the various tradeoffs quite well IMO. Judging by how popular they are, looks like a lot of folks agree.

GM

 

[Dan Wesnor]

I was using it sealed, both at Q=0.707 and Q=0.577. I don't hear the same problem in other 7-8" woofs. I imagine a higher Q would tighten things up, but that gives away the low-end response you're looking for in an 8" woofer.

 

[Michael R Price]

Hm, mine are vented 31 liters per driver tuned to 24Hz. This is overdamped and the response rolls off prematurely, around -3db at 50Hz anechoic. I have a room placement without significant (IMO) boominess, although it is difficult to determine just how bad my midbass peak is - SPL meter says it's about 6db centered at 50Hz but that positioning has better sound otherwise. And what's up with the 7.5 ohm resistor Adire put across the woofer terminals? Does that have anything to do with this bass problem? (Which, oddly enough, I haven't noticed, but I'll go listen for it sometime.)

 

[Brian Tatnall]

Chris I was wondering what you meant by this sentance.

If I was choosing a home theater speaker, I'd pick the Kit281s. If it's a 2 channel speaker for musical enjoyment I'd get the AV series.

Kyle Richardson from Acoustic Visions made the same comment about these two sets of speakers.

Why would one be better at HT and the other music? If the production is accurate wouldn't it be better at both? I understand some differences like a "brighter" tweeter is generally better for HT use because it has the wow factor and won't have a chance to be fatiguing.

Can I get some more explanation concerning why one wouldn't be better at both?

I would think that speakers which are better at music would be better than those that are better for HT. Generally, I think people are more critical when they listen to music because there isn't another sensory source like video that helps ignoring the acoustical imprefections.

 

[Michael R Price]

Well, the priorities vary depending on what kind of sound you want the speakers to make. I think a dynamic, impressive sound might be more important for home theater, and some prefer a smoother sound for music; that would explain the recommendation of Adire kits for HT and GR kits for music. However, some people also like to focus dynamic and impressive music sound, so you will have to consider which characteristic better suits your taste in music.

 

[Brian Bunge]

All the GR stuff that I've heard (the entire A/V line) has great dynamics even for HT. I've never heard any audible distortion from the A/V-1+'s I own except when running them Large. I'd imagine the Adire 281's may have even greater dynamics as I feel the LCC has a slight edge in this department. The only thing I feel the A/V-1+'s are lacking is in the deep bass, but that should be expected, IMHO.

 

[Martice]

The only thing I feel the A/V-1+'s are lacking is in the deep bass, but that should be expected, IMHO.

Hi Brian. I agree as well but let's make a clearer distinction between "DEEP BASS" and MUSICAL BASS because some may not know the difference.

The AV1+'s go pretty low unless you are into Hip Hop, rave music, club music and some organ music. I used to feel that the AV1+'s lacked in the low end department but after proper placement and calibration of my sub, they do extend pretty low. No they don't have the same effect as a sub but then again, most songs that don't depend on the the extreme low end (40hz and below) will feel full and satisfying depending on the size of your room.

If you are looking for "DEEP BASS" (bass that goes below 32hz) then get a sub but if you are into to contemporary music (bass above 40hz, musical bass) or music that doesn't use deep bass as it's sonic signiture, then the AV1+'s should do the trick if you don't have too large of a room.

 

[Brian Tatnall]

Hey guys,

I've sent e-mails to each company and received a number of responses from each.

I asked Adire about the

The forwardness that you here with the Kit 281's is the 6dB bump at 2kHz

They told me to look at the FR graphs.

I looked at the reviews and all the frequency response graphs and I couldn't find a sinle 6db bump anywhere around 2kHz. If anything at 2kHz the FR has just recovered from a dip from 1.5khz to 2kHz and then is back at 0db. I just can't find the bump and don't see it anywhere

I also looked at the resonance people have been talking about and from the D'Appolito review the spectral decay looks normal.

I having a hard time finding in the data where people are hearing the midrange break up in the 281 system.

Anyway, the new Adire kit is the 851 and will have a 4ohm load. This makes things even more interesting because any midrange problem the 281 may have should be taken care of.

I received price quotes on everything but the 251 which has not be released yet and the two systems look like this.

Adire:
F:81
R:81
C:81C

GR
F:A/V-3
R:A/V-1
C:A/V-1

Possible -
Adire
F:851
R:81 or 51
C:LCC or 81C

GR
F:A/V-3
R:A/V-1
C:A/V-3C

Looks like I'll just be waiting.

I think a few of the responses from this thread were deleted. Chris could you summarize what you siad about the midrange at loud levels for th GR system again?

 

[Greg Monfort]

>I was using it sealed, both at Q=0.707 and Q=0.577. I don't hear the same
problem in other 7-8" woofs. I imagine a higher Q would tighten things up,
but that gives away the low-end response you're looking for in an 8" woofer.
====
Huh?! A higher Q will further underdamp it, making it 'ring' worse. In
looking at the specs and Adire's IB response of this driver I see nothing to
indicate that the proper cab alignment won't 'tighten' it up WRT getting
good impulse/transient response.

Just looking at the two sealed alignments, they would have to be very
moderately driven to keep from going into overexcursion distortion on music
so it would be easy for them to 'color' the music. Frankly though, any
driver that 'snaps' as hard as this one does in breakup needs to be limited
to a fairly low XO point, ~500Hz with this one IMO. As you previously noted,
just because it's XO'd with a steep slope doesn't completely negate the
effects of the material properties that causes it, so there's always the
possibility that it won't sound as 'clean' as some others, but a better
alignment will help it a bunch regardless.

This reminds me of when we were batting around the specs/design for the
'basslist woofer' (which became the Shiva), and one of the goals I wanted
met was to be able to XO at 500hz/2nd order. When it finally arrived Dan
Wiggins said it was good for 450Hz, but the reality is that I found it
completely unacceptable above ~250Hz, and was only happy at 150Hz max, so
maybe this is what we're up against again. I think it mostly boils down to
personal preference though.
====
>And what's up with the 7.5 ohm resistor Adire put across the woofer
terminals? Does that have anything to do with this bass problem?
====
What does the driver's DCR measure? Adire says 5.48ohms, or is it closer to
3.17ohms? Do both drivers have them? Are the drivers wired in parallel or
series? What does the speaker's DCR measure?

GM