Emotiva Airmotiv B1+ Review (Bookshelf Speaker)

[cursive]

I too have the same question. If so, why not just dampening the port with weight and move the resonance higher up and at a lower volume.

This was exactly my thought. Could we use No Rez or some other dampening material to wrap the port on the inside of the speaker and change the frequency of the port resonance? Or could we change a straight port for a 90 degree port and eliminate or change the resonant frequency that's measured here?

I do also have a set of NHT SB1 which are non-ported and I've used on my desktop many times, but they are best crossed at 100hz or even 120hz which isn't a problem necessarily, but it does require a good subwoofer that can play flat to 120hz if not higher, which may be more expensive than some cheaper subs. NHT is one of the few companies that all of their speakers have been non ported, and can be had quite cheaply second hand, so worth a look for sure. Maybe I'll send some of these to Amir in the future.

 

[AverageJoeAudiophile]

I assume you are not following me correctly.

1- We are talking about stereo, a pair of speakers.

2- Very few AVRs have adjustable cross-overs for subwoofers. (I know just one, it costs $15K.) The crossover frequency is just one aspect of the crossover. What about slopes?

You can certainly make-do and have sound. It can be good sound even. That doesn't mean your engineering is correct.

1 - no shit

2 - What do you mean by adjustable? Any AVR with a subwoofer output will have an adjustable crossover point. You seem to be using the term adjustable in way that isn't common vernacular. Are you meaning frequency range AND slope? If so a mini DSP handles both for ~100$.

 

[sarumbear]

I too have the same question. If so, why not just dampening the port with weight and move the resonance higher up and at a lower volume.

Port resonance has nothing to do with the port material. It is caused by the resonating air inside the port, like it happens in an organ's pipe. Technical term is Helmholtz resonance. I tried to explain this on post #43

 

[sarumbear]

1 - no shit

I'm afraid I cannot continue when profanity, ignorance and lack of knowledge are mixed together.

 

[AverageJoeAudiophile]

I'm afraid I cannot continue when profanity, ignorance and lack of knowledge are mixed together.

Cool. You have nothing of value to add and don't seem to know the existence of cheap and powerful crossovers.

Thanks bud.

 

[cursive]

Port resonance has nothing to do with the port material. It is caused by the resonating air inside the port, like it happens in an organ's pipe. Technical term is Helmholtz resonance. I tried to explain this on post #43

Thanks for addressing this, this was the part of it I couldn't quite wrap my head around. So the air is what's resonating, not the port itself, makes more sense why it's harder to fix then. Is there any easy way to calculate where in a small box the null would be to direct where to put the opening of the port? As an end user is there a realistic way to improve this, or is it better to just use EQ and accept that it sounds pretty decent for a low priced speaker.

 

[respice finem]

...Any AVR with a subwoofer output will have an adjustable crossover point.

Well, in the analog world = passive sub, a typical AVR of today wouldn't even work with it.

Nonetheless, if you would pair the Emotiva with a current AVR with DSP, and an active sub, you can integrate them of course, how "smoothly" is a different question. My personal experience = "your mileage may vary" in a real room, I ended up with an Anti-Mode for the sub in my home cinema.

 

[sarumbear]

As an end user is there a realistic way to improve this, or is it better to just use EQ and accept that it sounds pretty decent for a low priced speaker.

You have to alter the structure of the box so much that you might as well design a new box/port combination and place the drive units and crossover in it.

The fundamentals of all musical sound is a basic sine wave. When you generate that within a reflective boundary standing waves happen. Check it if you are not familiar with them. At the null point of a standing wave there is no sound pressure. If you find that point and place the start of the port (the bit inside the box) then air inside the vent will not move, hence no resonance can happen. Naturally in real life the word "no" means "less" due to irregularities, but even halving the port resonance will eliminate the majority of the peaks we see in the frequency sweeps.

 

[sarumbear]

Well, in the analog world = passive sub, a typical AVR of today wouldn't even work with it.

Nonetheless, if you would pair the Emotiva with a current AVR with DSP, and an active sub, you can integrate them of course, how "smoothly" is a different question. My personal experience = "your mileage may vary" in a real room, I ended up with an Anti-Mode for the sub in my home cinema.

Besides, this thread is about a full-range speaker and post are about its measured port resonance anomaly. Not system design. @amirm has specifically asked us to stay on topic.

 

[respice finem]

Yes, I often forget which thread I'm in.
@topic: Though this may be, by definition, a fullrange speaker, I wouldn't really be happy with it as such anyway. As a surround speaker aided with a sub, all DSP controlled, maybe.

 

[AverageJoeAudiophile]

Well, in the analog world = passive sub, a typical AVR of today wouldn't even work with it.

Nonetheless, if you would pair the Emotiva with a current AVR with DSP, and an active sub, you can integrate them of course, how "smoothly" is a different question. My personal experience = "your mileage may vary" in a real room, I ended up with an Anti-Mode for the sub in my home cinema.

What do you mean by analog world? Why would an avr not work? Your AVR has an RCA out which has even low passed and potentially EQ'd. Your amp which will power your sub had an RCA in put.

 

[respice finem]

Your amp which will power your sub had an RCA in put.

I'm making no scenarios, I'm interpreting - and, to interpret what you wrote, what did you mean by the above?

 

[AverageJoeAudiophile]

What Sarumbear IMO meant, was an adjustable analog, passive crossover, to integrate a passive sub. What you mean is a digital DSP crossover in an AVR with RCA out for an active sub - this will "power" nothing, it will provide the signal to be amplified in that active sub.

Literally no one said anything about an RCA out powering anything. AND no one would use this speaker paird with a subwoofer of which has a passive low pass crossover.

Why are you making up ridiculously rare edge case scenarios?

 

[Dennis Murphy]

Hi Dennis would you be up for sharing those changes you made?

I have no problem with sharing, and have already sent my schematics off to several people. But I have no idea what the result would be with the + version unless the only change was in the crossover. For the record though, here are my circuits. NPE's would be required for the high value woofer caps because Poly's would take up way too much space and drain your checking account. You will literally need a magnifying glass to read these:

 

[richard12511]

On the contrary; on a small speaker like this a port is the only option. If you look at the chart below you will see that almost an entire octave below 100 Hz is generated by the port. Without the port the lowest bass guitar tone (60 Hz) will be around 10 dB down. Such a bass shy speaker is not useable as a full range speaker.

View attachment 123439

Even with the port, it's not a full range speaker, and not even close, so I kinda agree with trying to optimize performance for usage with a subwoofer.

 

[AverageJoeAudiophile]

I have no problem with sharing, and have already sent my schematics off to several people. But I have no idea what the result would be with the + version unless the only change was in the crossover. For the record though, here are my circuits. NPE's would be required for the high value woofer caps because Poly's would take up way too much space and drain your checking account. You will literally need a magnifying glass to read these:View attachment 123472View attachment 123473

Awesome!

 

[richard12511]

I see companies making these choices primarily to get the buyer to think "oh, well, it's ported so it must play low". The educated consumer may be wise to the fact that a subwoofer makes this moot. The astute consumer knows this and also understands the port design in such a low-priced speaker may create its own issues. There's a multitude of "what-if" considerations here. But, again, I come from the perspective that you're going to buy a subwoofer anyway... seal the port up, take out that +3dB octave-wide bump at 1kHz and enjoy a better sounding system (not to mention the strain taken off the woofer and thus the increased dynamic capabilities).

Couldn't agree more. I would never buy a speaker like this for the purpose of trying to run it full range, and I would hope that others wouldn't either.

 

[richard12511]

It is impossible to correctly cross an off-the-shelf speaker to a subwoofer without an adjustable active cross-over. As the proliferation of affordable external active cross-over is not going to happen anytime soon your solution will always generate a compromise, not to mention more than double the cost of two ported small speakers.

The cheapest commercial full range speaker I know of is like $7,000, and most are $20,000 or more. No way are you getting full range performance with a $250/pair speaker.

 

[amirm]

I would never buy a speaker like this for the purpose of trying to run it full range, and I would hope that others wouldn't either.

My standard for any speaker I test is that it is "good enough" to run full-range. They are made and sold that way.

Full range doesn't mean flat response to 20 Hz. It means there is enough bass there to enjoy music.

 

[richard12511]

This seems rather short sighted or I'm not following correctly. Any remotely modern AVR will have bass control and allow for appropriate crossover ranges. If it has preamplifier output or you choose a miniDSP your able to use the separates of your choosing.

Perhaps I'm misremembering, but I believe @sarumbear has said AVR's are unsuitable for music listening(correct me if I'm wrong).

While I disagree with that sentiment, I can see where not being able to use AVR's would make bass management more difficult. That said, minidsp has some good external solutions available now, though I don't have much experience with those.