Boston Acoustics A 25 Speaker Review

[xykreinov]

Thank you so much for this review, Amir. Impeccable timing, as these were my main speakers for the last 7 years but I just placed an order for the Focal Aria 906 yesterday.
Now I'm actually considering cancelling my order, if the Aria 906 is not a reasonable upgrade to what I already have. I have a room about 16ft2 room with somewhat low ceiling and intend to use them on my desk (elevated to about ear level). I am not playing at high volumes nor I intend to do that in the near future.

Am I making an unreasonable choice to try to change this speaker for the Focal (550€ delivered)?

Wow yeah, what timing.
Yeah, I wouldn't go for the Focal. It just doesn't seem like enough of an upgrade to be satisfactory, especially since you'd only be getting around $150 out of your Boston's.
If it were me, I'd save my pennies for something more substantial. The Arias would be a pretty big upgrade in terms of port design and overall tonality. But, I'd be looking in the $800+ range of passive speakers, if I were you. Maybe a nice used lower end Revel.

 

[Snuggiefart]

The Focal 906 is objectively a FAR better speaker than this Boston Acoustics. You have not made a mistake. The 906 is pretty large for desk usage, however.

I agree, from Amir's measurements made without EQ the difference between these and the Aria 906 is pretty clear. However, this improvement in response by EQ looks interesting so I'm gonna give my measuring mic and speaker position one more try with the A25, until the Focals are back on sale. I've cancelled the order (for now).
Taking into account the option to iron some of these differences out by EQ-ing the A25, in what metric does the Aria perform distinctly better than the A25? I guess THD in the lower ranges is where the Aria is objectively performing better?

 

[xykreinov]

I agree, from Amir's measurements made without EQ the difference between these and the Aria 906 is pretty clear. However, this improvement in response by EQ looks interesting so I'm gonna give my measuring mic and speaker position one more try with the A25, until the Focals are back on sale. I've cancelled the order (for now).
Taking into account the option to iron some of these differences out by EQ-ing the A25, in what metric does the Aria perform distinctly better than the A25? I guess THD in the lower ranges is where the Aria is objectively performing better?

The Aria most objectively performs better in port design. Considering your space might be cramped, that might make a big difference. The Arias generally have lower driver distortion than the A25s, but more substantially in the woofer. The A25 and Aria both have good directivity, which means EQ would work especially well for both.
So, with EQ, the main upgrade with the Aria would be bass extension and less distortion from the port. EQ can't fix port issues, and it can only extend bass at the cost of lowered max SPL.
Here's amir's review of the the Arias, in case you weren't aware: https://www.audiosciencereview.com/forum/index.php?threads/focal-aria-906-speaker-review.14085/

 

[radio3]

My apologies if this is somewhat off topic, but I imagine there might be a fair number of people here who would be interested in seeing some reviews of excellent affordable little speakers for Atmos. For example, Focal Domes, Morel SoundSpot, Gallo Acoustics To mount up high on wall or hanging as pendants.

Reason being that theyre secondary or tertiary in importance, and you gotta pony up for 4 of them, so affordability highly important, but we always want the best possible sound quality, of course.

 

[amirm]

My apologies if this is somewhat off topic, but I imagine there might be a fair number of people here who would be interested in seeing some reviews of excellent affordable little speakers for Atmos. For example, Focal Domes, Morel SoundSpot, Gallo Acoustics To mount up high on wall or hanging as pendants.

I am happy to test more of these if members send them in.

 

[amirm]

@amirm
How far is the speaker from a back wall ? and how far is the microphone ?

The back wall is probably 4 feet away from the speaker.

As to microphone, that is not material as it is part of the Klippel near-field scanner system to produce anechoic response equiv. to 2 meters but reported as 1 meter per standard.

 

[amirm]

I am wondering if the close proximity of a back wall or the microphone is why its showing a rising and ragged port response ? and also the resonances picked up on the impedance chart ?

No mic is used for impedance graph as that is an electrical response.

The port is just bad. If you put your ear close to it you hear very bad distortion. And the velocity is huge, likely causing turbulence. As I noted though, in my setup where the back wall is rather tar, I did not readily hear the port distortion.

 

[Snuggiefart]

Wow yeah, what timing.
Yeah, I wouldn't go for the Focal. It just doesn't seem like enough of an upgrade to be satisfactory, especially since you'd only be getting around $150 out of your Boston's.
If it were me, I'd save my pennies for something more substantial. The Arias would be a pretty big upgrade in terms of port design and overall tonality. But, I'd be looking in the $800+ range of passive speakers, if I were you. Maybe a nice used lower end Revel.

Yeah, I was really shocked this morning when checking the new reviews on the site. I am also considering waiting a bit and skip this price class. Still, this price range might be different in the EU than in the US and even a used Revel has quite a premium on it. And also vice-versa, the Aria 906 falls above that 800$ range in the US, while it's substantially cheaper in the EU.
I will look for passive speakers though, like you've said. I already have an amp that I believe should measure well (TPA3245EVM).

The Aria most objectively performs better in port design. Considering your space might be cramped, that might make a big difference. For the drivers, THD in the lower ranges is not much different on the Aria- both the A25 and Aria have pretty low woofer/tweeter distortion. The A25s have worse bass extension than the Arias. The A25 and Aria both have good directivity, which means EQ would work especially well for both.
So, with EQ, the main upgrade with the Aria would be bass extension and less distortion from the port. EQ can't fix port issues, and it can only extend bass at the cost of lowered max SPL.
Here's amir's review of the the Arias, in case you weren't aware: https://www.audiosciencereview.com/forum/index.php?threads/focal-aria-906-speaker-review.14085/

The cramped low ceiling and asymmetric layout of the room is also an important point here yes.
Valuable information about the port design, thank you. In my previous room I've used some light foam to close the ports on the A25. It was rather boomy and I had no option to move the speakers further from the wall behind them.

I am aware of Amir's review of Aria here, yes. Been lurking and comparing speakers with the spinorama for a long time and decided on the Arias vs the Elac DBR-62, which would be the same price for me in the EU. Well, I was sure about my decision until today's review of the A25's.

 

[ROOSKIE]

@amirm
How far is the speaker from a back wall ? and how far is the microphone ?
I am wondering if the close proximity of a back wall or the microphone is why its showing a rising and ragged port response ? and also the resonances picked up on the impedance chart ?
I dont see these artefacts in the S&V and Stereophile measurements. Not saying theirs are correct, maybe yours are more accurate, just observing differences.

Howdy, you might want to read up on the measurement systems being used here.
You question might be answered by doing some research into the Kipple and the Audio Precision Analyzer.
Very advanced measurement rig here. (and very expensive)
The gear is in his large garage and as far as I know there is a lot of space there.

 

[ROOSKIE]

No mic is used for impedance graph as that is an electrical response.

The port is just bad. If you put your ear close to it you hear very bad distortion. And the velocity is huge, likely causing turbulence. As I noted though, in my setup where the back wall is rather tar, I did not readily hear the port distortion.

I stated this earlier, when I had the A25 the port noise was terrible. Same with Boston M25 and even the M350. All needed a high-pass to ensure no farting and chuffing at higher SPL.
I am an old school Boston fanboy from when I started this hobby and despite being excellent otherwise all 3 of those speakers had ports to small in diameter for the velocity at volume. I could not recommend any of them without such a filter.

 

[Robbo99999]

Cheers for the review Amir, I liked the technical breakdown you gave in your Listening Tests, aids in understanding.

Not a bad speaker, the good directivity along with a spin that be relatively easily EQ'd and for a good price seem like the main takeaways for me.

 

[Lorenzo74]

This is a review and detailed measurements of the Boston Acoustics A 25 bookshelf speaker. I purchased these a while back at a discount. Seems that they were originally released back in 2011 for US $300 a pair. At the time I purchased them the price had dropped to US $180 a pair. There were taxes and shipping costs added to the price. After discount, my net cost was $155.

The fit and finish of the speaker belies its very low price:

View attachment 94213

As you see there is some kind of faux leather surrounding the front baffle. Same is used underneath which is useful in keeping the speaker planted. Sides are gloss which gives the speaker fair bit of class. The cabinet feels dense, solid and heavy for its size.

Back panel shows nice provisions for hanging the unit and same leatherette finish:

View attachment 94214

Hard to imagine this speaker is being sold for so little. Externally anyways....

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

I performed over 100 measurement which resulted in error rate of more or less 1%.

Temperature was 58 degrees F. Measurement location is at sea level so you compute the pressure.

Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.

Reference axis was the tweeter center.

Boston A 25 Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

View attachment 94215

I must say at first I thought this was rather chewed up. But if we ignore the upper frequencies above 10 kHz, the rest is not too bad. We have a bit of peaking around 900 Hz. And a dip around 3 kHz.

Directivity is actually decent which means we can a) EQ the response and b) response will not be too room dependent.

The issue at 900 Hz becomes obvious when we look at the nearfield measurements of each sound radiating element:

View attachment 94216

The port becomes a bit crazy above its intended response and generates a couple of peaks. In addition, we see the tweeter having rather non-flat response.

The tweeter seems to have a steeper roll off than the woofer causing the dip in the crossover region.

Back to our spinorama, here is our early window reflections:

View attachment 94217

Like most speakers, floor reflections have a large dip and is best avoided with a thick carpet (which my listening room has).

Predicted in-room response is:

View attachment 94218

Impedance curve shows the resonances we have discussed:

View attachment 94219

Horizontal beam width is actually quite decent:

View attachment 94221

As is contour of the same:
View attachment 94222

They have made an attempt to narrow the gap between the woofer and tweeter and it shows in better vertical response:
View attachment 94223

Edit: forgot the distortion graphs:
View attachment 94228

View attachment 94229


Boston A25 Listening Tests
I placed the A25 in my usual far-field setting. First impression was positive. Certainly better than casual glance of the spin data. Some touch up EQ nicely lifted the response:
View attachment 94224

I tried to lift the dip but it subjectively made the speaker sound bright on some tracks so I took it off. As I noted earlier, I have a thick carpet so the predicted in-room response for me is better than what I showed.

The first filter is to get rid of distortion. It took away a bit of bass so you may want to play with it. The dip to get rid of the resonance was effective of making the sound lighter and vocals to stand out a bit more which I liked. The final shelving was to get rid of occasional brightness depending on track. I hate the fact that we have no production standards so sometimes seems impossible to actually tailor the overall "target curve."

Once there, the sound was quite nice. I listened for good 30 minutes and track after track sounded beautiful. Here is an example from Gait Kelin Kromhof:

View attachment 94225

Sorry, there is no youtube track for it. It is superb music that is very well recorded and it sounded great on the A25.

Dynamics were superb here and I could detect no sign of distortion at very high volumes. That said, if you listen to the port in the back, it sure sounded distorted and badly so. My back wall is from far from the speaker so I could not hear it from the front. If your situation is different, then the experience may not be as rewarding as it was for me.

Conclusions
The fit and finish of the Boston Acoustics A25 matches a speaker north of $800 a pair. It is hard to imagine how they pulled it off at such a low price. Objectively, the response is not ideal but somehow the mistakes are not that big with respect to audibility and easily corrected. While the speaker seems discontinued, searching for good prices as I did on clearance is an excellent idea. You will certainly get a speaker with far more power capability and better tonality than most budget speakers.

I am going to put the Boston A 25 on my recommended list.

------------
As always, questions, comments, recommendations, etc. are welcome.

Could no longer walk in our garage. So took out of main barbeque grill and smoker and put them on the deck. Now I have more space and ability to cook in winter just as well! Why do I say this? Because it sure would be good to have some money sent my way for meet to smoke! Have to eat good in winter or depression can set in with the gloomy days we have!

Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

I can't help admiring what the Boston Acoustics design team has achieved with this inexpensive speaker. I'm not surprised that SM liked it as much as he did.—John Atkinson
Thank you JA for your last sentences.

Thank you Amirm for your time, You take Audio philers into XXI c. with Science.

sometimes I’m wondering how great engineering didn’t survive to not the customer judgement but to marketing decisions.

Hope those people (B. A. design team) are doing today excellent products enjoyed by many of us.
My Best
L.

 

[thewas]

Looks like fairly similar response from ~150Hz to the Q Acoustics 3010 also measured by Sound & Vision,

Not a surprise considering both the Boston and Q Acoustics were engineered and tuned by the known Karl-Heinz Fink and his team. https://www.finkteam.com/
Would be interesting to measure the new 12th Wharfedale Diamond generation which was also tuned by them.

 

[tsanguine]

My first pair of speakers purchased by my father in 1992 were Boston Acoustic HD5's. I still have them as well as HD8's and one of their centers. I've always wanted some of the M90s but never willing to shell out the money. I've considered sending mine to Amirm but the HD8's need to be refoamed first. Maybe one of these days I'll load up my car and go visit. He's only four or five hours away.

I could bring...
Behringer 212XL
BA HD5 and HD8
DCM Timewindow
Ohm Walsh Sound Cylinder
Polk Audio Monitor 7b I think with the Peerless Tweeter
Athena AS.B1
NHT 1.3a

As well as...
Focal Elear
Dan Clark Aeon2 closed

 

[Snuggiefart]

I stated this earlier, when I had the A25 the port noise was terrible. Same with Boston M25 and even the M350. All needed a high-pass to ensure no farting and chuffing at higher SPL.
I am an old school Boston fanboy from when I started this hobby and despite being excellent otherwise all 3 of those speakers had ports to small in diameter for the velocity at volume. I could not recommend any of them without such a filter.

Would you recommend a HPF for the A25 at normal SPL levels. Care to share the HPF filter setting you've used in the past for the A25?

 

[TNT]

When you rotate, is it around the mechanical or acoustical centre?

//

 

[ROOSKIE]

Would you recommend a HPF for the A25 at normal SPL levels. Care to share the HPF filter setting you've used in the past for the A25?

Howdy, well sort of depends.
Really bass heavy music might start chuffing a bit even at medium volumes.
It is very content dependent. If you are a jazz, acoustic, soft vocal type you might never get chuff. Electronic stuff such James Blake, Massive Attack, Labradford, Daniel Avery, Drum and bass heavy stuff, ect is going to chuff.
I honestly don't remember on the A25.
The M25 I had the longest of the three (several years in rotation. I love this speaker by the way, seriously good beyond the port chuff). It did pretty well at 60-65hrz, it would be even better at 100-120hrz (I believe there was/would be zero chuff crossed here, even from inches away). (@60/65 from what I remember it only chuffed crossed here on the worst case stuff)
The M350 only chuffed badly at really high volume but that is a problem because IMHO higher SPL is what towers are for, oh well, cross that one over @ maybe 50hrz.
The main thing is to find out the Port tuning frequency. Usually the port will chuff the most around that, slightly above it-on it- and then of course below the tuning frequency.
I all cases I used a 4th order electronic filter as that was all I had at the time & I have no idea how other slopes would compare.

PS The A25 really needs bass support anyway so if you buy a set deff grab a sub. The M25 actually can go sort of low fun such a tiny speaker, still needs a sub due to the chuff but at lower volumes could get away without a sub.

 

[Snuggiefart]

Howdy, well sort of depends.
Really bass heavy music might start chuffing a bit even at medium volumes.
It is very content dependent. If you are a jazz, acoustic, soft vocal type you might never get chuff. Electronic stuff such James Blake, Massive Attack, Labradford, Daniel Avery, Drum and bass heavy stuff, ect is going to chuff.
I honestly don't remember on the A25.
The M25 I had the longest of the three (several years in rotation. I love this speaker by the way, seriously good beyond the port chuff). It did pretty well at 60-65hrz, it would be even better at 100-120hrz (I believe there was/would be zero chuff crossed here, even from inches away). (@60/65 from what I remember it only chuffed crossed here on the worst case stuff)
The M350 only chuffed badly at really high volume but that is a problem because IMHO higher SPL is what towers are for, oh well, cross that one over @ maybe 50hrz.
The main thing is to find out the Port tuning frequency. Usually the port will chuff the most around that, slightly above it-on it- and then of course below the tuning frequency.
I all cases I used a 4th order electronic filter as that was all I had at the time & I have no idea how other slopes would compare.

PS The A25 really needs bass support anyway so if you buy a set deff grab a sub. The M25 actually can go sort of low fun such a tiny speaker, still needs a sub due to the chuff but at lower volumes could get away without a sub.

Thank you. I'll try applying it around 60Hz, as this supposedly is the tuning frequency at least according to Stereophile tests:

The low-frequency saddle centered on 60Hz in the impedance-magnitude trace suggests that this is the tuning frequency of the rear-facing reflex port..

I owned a Boston ASW 250 sub in the past and from what I can recall, It played pretty well with the A25s. Sold it after moving to a new place to avoid annoying my new neighbors too much.
As a sidenote, this is in room FR measurement I've taken from my right A25 speaker at my old place before (red) and after EQ (green with yellow border):



I've noticed that I'm missing 5dB from the y scale, sorry for that, It's an old screenshot.

 

[teej]

I paid full-retail for these a few years back, and I am delighted to see them get a proper ASR review. I originally went into my local stereo shop in search of Elac Debut's, but he sold me on these instead, and I've been delighted by their performance. A little bright, yes, but also fun and engaging. My only gripe is that the plastic coating on the piano-black gloss sides and edges was an absolute pain to remove entirely. Apart from that these are some really excellent bookshelves. I've since replaced them with Unifi's (and again with Unifi 2.0's), but I have vowed to always find a place for them somewhere. They currently live (woefully underused) in my gameroom as my "video game system" speakers.

 

[Eetu]

I found a pair of these Boston Acoustics A25s dirt cheap and I want to do digital active crossovers since I have a MiniDSP 2X4HD and two Aiyima A04s unused laying around. I have a UMIK mic and know how to take gated measurements.

I'm also going to seal the port since it seems like a weak link. They are going to be crossed over with subs.

I'm going to linearise the response and optimize the midwoof-tweeter crossover (change XO freq and use steep filters). Looking at the data available, what could be the optimal XO freq?

(This is a just-for-fun experiment and I'm not sure if I'm ready to simulate with VituixCAD for example, keeping it REW at least for now..)