Adam A5X Review (Powered Studio Monitor)

[YSC]

Fantastic report. I have been using a pair (German built) for family entertainment with a pair of small subs in a problematic cubic room. With Dirac Live and not much 'treatment', the 1K notch is not noticeable. There are MUCH bigger problems with room modes in the real world. Your lab grade data confirms what I have measured with REW and Audio Tools, indoors and outdoors. Now I wonder how toying with the ports can possibly improve this. In a small room, I thought that front ports might be more desirable so I could place them closer to the wall - maybe not. Placement too close to the front wall is still undesirable in any case especially without treatment at front or back. Id like to see what sub woofer you would suggest for these units and suggested crossovers designs. At this point in life, my ears have 1/2 the bandwidth of the tweeter ... sigh.

agree that the room modes are way more problematic than that found in lab narrow dip. but regarding to placement to the wall I do think place them as close as possible then attenuate the boosted bass by 4-6db works much better than having some huge dip in FR due to cancellation

 

[FeddyLost]

Now I wonder how toying with the ports can possibly improve this.

I think, making some kind of variovent (adding thin layer of fluffy cloth) might reduce 1K sound of port, but it will definitely need some experiments.

 

[YSC]

I think, making some kind of variovent (adding thin layer of fluffy cloth) might reduce 1K sound of port, but it will definitely need some experiments.

if that worked magic without breaking anything, I feel shame of adam for not perfecting that little stuff.

 

[vlad335]

My monitor is supposed to arrive back here tomorrow (Thanks Amir for shipping it back fast!)
I am going to play around with it and see if i can mitigate the effect of the port. Ordered a microphone and downloaded REW so I'm going to learn measuring. Seems pretty daunting right now but a necessary skill I do need to learn

 

[vlad335]

think, making some kind of variovent (adding thin layer of fluffy cloth) might reduce 1K sound of port, but it will definitely need some experiments.

Yeah, I'm open to suggestions.

 

[aranido]

I have the A7X. Unfortunately I do hear hiss. I even purchased another pair to see if mine were broken and they also had hiss (I returned them).

 

[phoenixsong]

I wonder how the Neumann KH120 will fare as it shares a similar frontal port configuration

 

[YSC]

I wonder how the Neumann KH120 will fare as it shares a similar frontal port configuration

it seems that from all available tests the KH120 don't have that outlier peak/dip problem within the FR.

 

[KSTR]

The optimized, non-standard design of the KH120 ports has already been discussed, here and elsewhere.

 

[phoenixsong]

The optimized, non-standard design of the KH120 ports has already been discussed, here and elsewhere.

Would it be to your convenience to attach some quick links?

 

[KSTR]

Would it be to your convenience to attach some quick links?

https://www.audiosciencereview.com/...ased-speaker-designs.6441/page-29#post-211742
https://www.audiosciencereview.com/...kh120-disassembly-pictures.11975/#post-346968

 

[ChuckL]

I think, making some kind of variovent (adding thin layer of fluffy cloth) might reduce 1K sound of port, but it will definitely need some experiments.

I took my Adam and tried a simple experiment. Stuffed a soft, lint free, low cal, cloth in the ports and reran the response.
Here is a before-after in a room using REW. Taken at 1 meter about the centerline of the woofer. You can remove the notch, but bend the low frequency tuning. More finess in materials may result in a better compromise. Need to look at distortion too. Would you want to EQ out the low end rolloff and try to match a sub? I'll go for the notch - I cannot hear it. Notice presence of some room modes. The slope for the "normal design" has some basis on other measurements too, but there is a new slope added with the modified port, as you would expect. About 6 db droop. My first post with a pic - hope this works !

 

[dfuller]

I took my Adam and tried a simple experiment. Stuffed a soft, lint free, low cal, cloth in the ports and reran the response.
Here is a before-after in a room using REW. Taken at 1 meter about the centerline of the woofer. You can remove the notch, but bend the low frequency tuning. More finess in materials may result in a better compromise. Need to look at distortion too. Would you want to EQ out the low end rolloff and try to match a sub? I'll go for the notch - I cannot hear it. Notice presence of some room modes. The slope for the "normal design" has some basis on other measurements too, but there is a new slope added with the modified port, as you would expect. About 6 db droop. My first post with a pic - hope this works !View attachment 128582

Potentially some measurement error, but does the high end look smoother to anyone else too?

 

[phoenixsong]

Potentially some measurement error, but does the high end look smoother to anyone else too?

Yeah, some differences from 3-6.5kHz

 

[YSC]

I took my Adam and tried a simple experiment. Stuffed a soft, lint free, low cal, cloth in the ports and reran the response.
Here is a before-after in a room using REW. Taken at 1 meter about the centerline of the woofer. You can remove the notch, but bend the low frequency tuning. More finess in materials may result in a better compromise. Need to look at distortion too. Would you want to EQ out the low end rolloff and try to match a sub? I'll go for the notch - I cannot hear it. Notice presence of some room modes. The slope for the "normal design" has some basis on other measurements too, but there is a new slope added with the modified port, as you would expect. About 6 db droop. My first post with a pic - hope this works !View attachment 128582

Just want to clarify as English isn’t my first language, by stuffing the port, do you mean basically block and fill the port by the cloth or use it as a lining?

 

[ChuckL]

UPDATE - Using a bit more fitness with some acoustic foam (wedge) cut to fit with a slight compression fit into each port.
Figure A: 1/12 Oct smoothing aimed at woofer center, 12" (0.3m) distant showing the notch removed. Figure B: 1 octave smoothed at tweeter level 1m distant (~ far field). Figure A should show some falloff in high frequencies - in the shadow of the tweeter.
The room has modes around 120 Hz below and above and REW will not remove those with a 10 sec sine sweep. This does show the foam plug will disrupt the low end but remove the 1 KHz notch, I don't have any data on material transmissibility, but such foam would probably have a lot more absorption at 1 kHz than 60 Hz. You want a low pass filter which this is approximating, but the vented box design is still disrupted.

Enough science fair for me! The tilted LF response (Fig B) will make for a more troublesome to match a subwoofer. Sorry to disrupt amirm's test report.
(Microphone (AUDIX TM-1 is uncalibrated except for SPL level.)

 

[dfuller]

UPDATE - Using a bit more fitness with some acoustic foam (wedge) cut to fit with a slight compression fit into each port.
Figure A: 1/12 Oct smoothing aimed at woofer center, 12" (0.3m) distant showing the notch removed. Figure B: 1 octave smoothed at tweeter level 1m distant (~ far field). Figure A should show some falloff in high frequencies - in the shadow of the tweeter.
The room has modes around 120 Hz below and above and REW will not remove those with a 10 sec sine sweep. This does show the foam plug will disrupt the low end but remove the 1 KHz notch, I don't have any data on material transmissibility, but such foam would probably have a lot more absorption at 1 kHz than 60 Hz. You want a low pass filter which this is approximating, but the vented box design is still disrupted.

Enough science fair for me! The tilted LF response (Fig B) will make for a more troublesome to match a subwoofer. Sorry to disrupt amirm's test report.
(Microphone (AUDIX TM-1 is uncalibrated except for SPL level.)
View attachment 128644

Looks like when you plugged the ports you essentially converted it into a sealed box - the roll-off resembles it somewhat until it hits the high pass filter.

 

[ChuckL]

Yep - I have tried partial insertion of foam, taping a 1/8" thick cloth- backed foam (car ceiling foam). Both disrupted the port resonance. With 50% masking of the ports with 1/8" foam cloth, the unit behaves ~ normally including the notch. Foams, screens, etc, are probably mostly resistive and it appears that way. What one would want is a low pass filter (with a reactive property), maybe a tuned pipe if this is realizable at the dimensions needed. Foams have increasing absorption vs. frequency, as wall treatment, but that does not mean they are reactive vs. resistive. Ho hum.

 

[Serge]

Of course you should re-EQ the thing and you will loose headroom and have increased distortion when EQ'd to the same original response.
When used with a subwoofer all of this is a non-issue but setting up a subwoofer correctly is a hell of a non-trivial task for a lay-person...

Did I understand you correctly that using a subwoofer with these monitors solves the issue with sharp dip at 1.1 kHz? I.e. the less bass the A5X woofer plays, the less this 1.1 kHz dip pronounced?

 

[ChuckL]

Did I understand you correctly that using a subwoofer with these monitors solves the issue with sharp dip at 1.1 kHz? I.e. the less bass the A5X woofer plays, the less this 1.1 kHz dip pronounced?

No sir. What I mean is: If you elect to plug the ports, (removing the apparent 1 kHz notch), this produces a quicker rolloff in the bass and it does not appear "maximally flat". This may cause you to have a somewhat more complicated task in matching to a subwoofer (using anechoic data). In a room, EQing the bass also attempts to smooth out room resonances, and the extra droop in the Adam bass is yet another 6 dB hole to fill. With most engineering: "It Depends" [on where your sub crossover is placed...]

I also noted that the distortion at moderate levels in some cases doubled in the 50-100 ish region with the ports attenuated. The driver is having to work harder and not assisted by the resonance of the box as ported (about 62 Hz). This condition occurs at 6 dB reduced output in the same range, so when EQ'd back to flat, I assert that there will be more distortion yet. (I have not proven that by measurement.)
* With no foam (OEM), the THD is 4.7% at 63Hz, 1% @ 300 Hz, 87 dB SPL @ 1 meter, tweeter elevation (1.66m)
* With foamed ports, the THD is 10.2% at 63Hz, 1% @ 300 Hz.

I have not attempted to re-EQ my system with the ports plugged. I need more room treatment before I attempt EQ any further (see the thresh on room EQ and Floyd Toole's papers and books.)
Hope this helps.

PS - Above I indicated the FOAM acts as a low pass filter. This was the INTENT of the test - I don't believe that is happening - It appears "resistive".