Adam T8V Studio Monitor Review

[andreasmaaan]

In Adam's manual in the speaker positioning section of the T Serie, they state at page 8 "For the flattest bass response, each monitor should be placed at least 16 inches from the nearest wall". That's a figure more familiar to me for rear firing ports but I don't really have the rigorous metric to caracterise what is an optimal distance.

That seems correct for this speaker, but it's not because the port is rear-firing. Rather, it's because the speaker has an anechoically flat bass response, i.e. it is not designed such that its bass is intended to be reinforced by the front wall. This would also be correct if the speaker measured the same but had its port on the front.

Have a look at the frequency range in which the port is making a dominant contribution to the speaker's output. It's really only below 60Hz, although arguably it continues making a useful contribution up to just above 100Hz.

The wavelength of say 80Hz, which is already well into the frequency range in which the woofer's output is dominant, is about 14 feet. In centre of the port's operating band, at around 42Hz, one wavelength is around 27 feet.

There is just not going to be a more than negligible change in the speaker/boundary surface interaction at these frequencies when we are talking about changes in distance of one or one and a half feet... Indeed, the question of where on the speaker the port's exit is located is just not going to be relevant at all at these frequencies (although the location of the port inside the box is important, for reasons unrelated to this).

There would be a potential change in the speaker's output, however, if the speaker were placed so close to the front wall that the port's effective internal volume of air were increased. However, given Amir's description of the setup in post #90, it seems that there was adequate clearance for this not to be an issue.

Quite aside from questions regarding the location of the port, however, he did of course have the speakers suboptimally close to the wall.

 

[tmtomh]

As usual around here, I've learned something new in this thread - this info on ports is very helpful and explains a lot. Also reduces my hesitancy to consider rear-ported speakers in general.

As for these Adams, maybe I'm overreacting, but I'm gobsmacked at the bass extension, the overall perceived sound quality, and the LACK OF HISS! - all for $600 a pair. (For me self-noise/hiss is a total deal-breaker - in my experience this is a nuisance even with medium-field listening.)

It also seems to me that the 4.6k dip, while strange, is quite narrow, and I would guess the THD spikes there in part because the speaker's output is lower, meaning that THD goes up proportionally and not necessarily in an easily perceivable, absolute sense when listening to full-range audio signals.

That 2k dip is more concerning, given where in the audible spectrum it is. But IMHO it's the only meaningful negative on these, and as noted above with a modest EQ bump with an appropriately narrow Q, probably easily remedied. Otherwise these seem fantastic.

 

[Pearljam5000]

Somewhat relevant

 

[PeteL]

That seems correct for this speaker, but it's not because the port is rear-firing. Rather, it's because the speaker has an anechoically flat bass response, i.e. it is not designed such that its bass is intended to be reinforced by the front wall. This would also be correct if the speaker measured the same but had its port on the front.

Have a look at the frequency range in which the port is making a dominant contribution to the speaker's output. It's really only below 60Hz, although arguably it continues making a useful contribution up to just above 100Hz.

View attachment 90241

The wavelength of say 80Hz, which is already well into the frequency range in which the woofer's output is dominant, is about 14 feet. In centre of the port's operating band, at around 42Hz, one wavelength is around 27 feet.

There is just not going to be a more than negligible change in the speaker/boundary surface interaction at these frequencies when we are talking about changes in distance of one or one and a half feet... Indeed, the question of where on the speaker the port's exit is located is just not going to be relevant at all at these frequencies (although the location of the port inside the box is important, for reasons unrelated to this).

There would be a potential change in the speaker's output, however, if the speaker were placed so close to the front wall that the port's effective internal volume of air were increased. However, given Amir's description of the setup in post #90, it seems that there was adequate clearance for this not to be an issue.

Quite aside from questions regarding the location of the port, however, he did of course have the speakers suboptimally close to the wall.

Thanks for the thorough explanation. I guess it was a misconception on my parts, the few rear fired speakers that I had in my rooms over the years did happen to be susceptible to low end problems when too near the wall, but I agree there are more factors to consider of course.

 

[daftcombo]

It also seems to me that the 4.6k dip, while strange, is quite narrow, and I would guess the THD spikes there in part because the speaker's output is lower, meaning that THD goes up proportionally and not necessarily in an easily perceivable, absolute sense when listening to full-range audio signals.

Are you sure it works like that? I thought the distortion was measured relatively to a SPL measured at say 1kHz.

 

[andreasmaaan]

Are you sure it works like that? I thought the distortion was measured relatively to a SPL measured at say 1kHz.

That's certainly the standard, although it can be referenced to either the fundamental or the harmonic frequency. I imagine Amir would have mentioned it if it was the latter (and the plots would likely look quite different).

EDIT: actually, maybe I misunderstood you. The distortion is normally referenced to the SPL at the frequency of the fundamental. So, if there is a dip in a transducer's response at a particular frequency, there will tend to be a spike in HD at that same frequency, as @tmtomh described.

 

[temps]

Not very encouraging in a studio monitor lol. Those tiny AMT tweeters are prone to quite high distortion. I wonder if this is what you were hearing?

Quite likely.. my microphone & setup weren't good enough to measure that, though. One of the bigger problems was around 2khz, all through the crossover region. The original version of the A5 series only lasted 2 years (iirc). The woofers were changed on the "X" revision. I wonder if the hasty revision was because of a substandard woofer.

It was an interesting experience finally replacing them... I was simultaneously so happy with the new speakers and so angry I had kept the A5s for so long. I kept think my translation issues were my fault. As soon as I switched to Sonarworks calibrated headphones, all those issues disappeared literally overnight... so much time wasted, for years. Ugh.

The T series is a great line for ADAM but I can't say I like anything else they make these days.

 

[daftcombo]

That's certainly the standard, although it can be referenced to either the fundamental or the harmonic frequency. I imagine Amir would have mentioned it if it was the latter (and the plots would likely look quite different).

EDIT: actually, maybe I misunderstood you. The distortion is normally referenced to the SPL at the frequency of the fundamental. So, if there is a dip in a transducer's response at a particular frequency, there will tend to be a spike in HD at that same frequency, as @tmtomh described.

I learnt something, thanks!
And it looks less worrying now

Things are different for this graph, right?
https://www.audiosciencereview.com/...-96-db-thd-distortion-measurements-png.90119/

 

[andreasmaaan]

I learnt something, thanks!
And it looks less worrying now

Things are different for this graph, right?
https://www.audiosciencereview.com/...-96-db-thd-distortion-measurements-png.90119/

Yeh, there we're seeing the tweeter getting pushed towards its limits.

 

[daftcombo]

Yeh, there we're seeing the tweeter getting pushed towards its limits.

I meant: on that latter graph, SPL is varying according to frequencies?

 

[infinitesymphony]

It was an interesting experience finally replacing them... I was simultaneously so happy with the new speakers and so angry I had kept the A5s for so long. I kept think my translation issues were my fault. As soon as I switched to Sonarworks calibrated headphones, all those issues disappeared literally overnight... so much time wasted, for years. Ugh.

Some people I respect have moved to mixing on HD800s with Sonarworks calibration. Which headphones are you using?

 

[andreasmaaan]

I meant: on that latter graph, SPL is varying according to frequencies?

Ah then I'm not sure what you mean actually. Different how?

 

[daftcombo]

Ah then I'm not sure what you mean actually. Different how?

When you run a sweep, what goes out of the DAC is all at, say, 2.2V. The SPL measured depends on the frequency and that's how you obtain a frequency response graph.

When Amir measures distortion, does he run a sweep like that? or does the voltage coming out of the DAC change so that the SPL of the fundamental of each frequency gets measured at 86dB / 96dB?
And is it the same for the three distortion graphs?

 

[Music1969]

Or are you talking about the on-axis dip at the crossover point? This is certainly something I would expect DSP equalisation to remedy. Perhaps Adam was going for a house tuning here. It is a bit surprising IMO.

Hi, yes I was surprised by on axis dip also

 

[andreasmaaan]

When you run a sweep, what goes out of the DAC is all at, say, 2.2V. The SPL measured depends on the frequency and that's how you obtain a frequency response graph.

When Amir measures distortion, does he run a sweep like that? or does the voltage coming out of the DAC change so that the SPL of the fundamental of each frequency gets measured at 86dB / 96dB?
And is it the same for the three distortion graphs?

Ah sure, I understand now. Yeh the former is correct. This sweep is run with a constant voltage input into the speakers (however many volts it takes to get to an average level of 96dB in - I'm guessing - the midrange).

EDIT: ok so maybe I misunderstood you slightly a second time haha

There are two kinds of distortion graph that Amir uses. One is % HD, and the other is HD SPL (in dB).

The former is referenced to the fundamental frequency. The latter is not, so what you see on the graph is what you get. You can tell which is which by looking at the vertical scale, i.e. it will either be in dB or in %. Hope that finally made sense!

 

[daftcombo]

Ah sure, I understand now. Yeh the former is correct. This sweep is run with a constant voltage input into the speakers (however many volts it takes to get to an average level of 96dB in - I'm guessing - the midrange).

So on the first two graphs (86dB and 96dB), disto is a % of the fundamental (which can be at 86 but also at 85 or 87 dB...) whereas on the third it is in absolute SPL?
That's why the % are not convertible in dB in that case, I think.

 

[andreasmaaan]

So on the first two graphs (86dB and 96dB), disto is a % of the fundamental (which can be at 86 but also at 85 or 87 dB...) whereas on the third it is in absolute SPL?
That's why the % are not convertible in dB in that case, I think.

Exactly Sorry I edited my previous post just at the same time as you replied.

 

[daftcombo]

Exactly Sorry I edited my previous post just at the same time as you replied.

Now I get it. I was puzzled that I couldn't convert 1% as -40dB as usual.
Of course the third graph is the more realistic, except if someone wants to EQ and then it will be the two firsts.

 

[andreasmaaan]

Now I get it. I was puzzled that I couldn't convert 1% as -40dB as usual.
Of course the third graph is the more realistic, except if someone wants to EQ and then it will be the two firsts.

Yeh that's a good way of thinking about it.

 

[temps]

Some people I respect have moved to mixing on HD800s with Sonarworks calibration. Which headphones are you using?

I went with Beyerdynamic DT880 Pros... I don't quite remember why. The EQ they require is fairly intense. I think maybe I wanted a dual personality headphone? With the calibration they're ruler flat, without it, they are very hi fi. Something like an HD600 would have been flatter to start and needed less EQ.