Elac Debut Reference DBR-62 Speaker Review

[test1223]

I take that absorbing internal sound transmission of the cabinet is beneficial or desired, but isn't a loudspeaker primarily designed to benefit from the cabinet internal amplification?

The bass reflex "part" of the cabinet needs and uses the airborne sound inside the cabinet. Ideally the sound which has the bandwidth of the bassreflex port shouldn't be lowered by absorbing material. The standing waves however are not desired because they cause peaks with a high amplitude and a small bandwidth aka resonances. Resonances are one of the worst distortions you can get. From that perspective an ideal bass reflex cabinet should have standing waves which are in the higher frequencies. Ideally the bass driver should already be faded out completely by the crossover so that the standing waves aren't exited. But in reality you have to deal with compromises.

Can you explain a bit about normal modes and how can bitumen shift them to lower frequencies due to the higher mass? Isn't a thin bitumen adhesive pad irrelevant to the speaker's total weight? I have also read that bitumen doesn't absorb bass, it actually reflects it, but it absorbs the wall's resonance. It might pair well with felt and/or polyester sheet on it, so it absorbs some of it aswell. It would absorb air pressure for the bass port, though.

All cabinet walls can be seen as membranes where a bitumen foil adds mass which lowers the resonance frequency aka the first eigenmode. This eigenmode typically transmits the most energy into the cabinet and therefore also to the outside air since it is coupled by all outside surface movement of the cabinet walls.

The bitumen can absorb surfaces movements to some extent but it is frequency dependent and higher frequencies are absorbed much more efficiently.

Since the first normal mode is relatively low with an unbraced wall of a typical box bitumen can't do much in these lower frequencies.

But bracing can. Ideally it prevents the movement of the part of the wall with the highest amplitude, which is the middle of the cabinet wall. This shifts the normal mode of the cabinet wall way up. Ideally so much up that material like bitumen or material which absorbs airborne sound works effectively.

How can you add bracing to a finished cabinet such as the DBR62?

You can mount two or more wood parts through the bass opening of the cabinet and glue them together and against the cabinet walls.

Focus on the parts of the cabinet walls which have the largest unbraced area. A support for the magnet of the driver can also be beneficial since it can also move and cause structure borne sound, which travels through the cabinet. Have a look at the enclosure of the e.g. a KEF LS 50 they put in a lot of effort.

 

[wyup]

The bass reflex "part" of the cabinet needs and uses the airborne sound inside the cabinet. Ideally the sound which has the bandwidth of the bassreflex port shouldn't be lowered by absorbing material.

How does the bassreflex port work, by amplifying (resonating) internal sound waves within its bandwith, or just by air pressure exiting the port? (it looks as it works by pumping air out)

All cabinet walls can be seen as membranes where a bitumen foil adds mass which lowers the resonance frequency aka the first eigenmode.

But isn't resonance frequency (caused by standing waves) dependent on cabinet internal measurements (that coincide with its wavelength) and not its mass?

But bracing can. Ideally it prevents the movement of the part of the wall with the highest amplitude, which is the middle of the cabinet wall. This shifts the normal mode of the cabinet wall way up. Ideally so much up that material like bitumen or material which absorbs airborne sound works effectively.

The Elac DBR62 already features an internal bracing in a H-shaped middle wall. So bitumen pads may work well then, absorbing wall resonances and letting bass reflect into the port.

My question is: since dampening material only absorbs sound from the woofer (because the tweeter is enclosed), can't we unbalance the response of the speaker tuned by the designer? I mean, on one hand, material like felt or polyfill reduce the airflow of the cabinet, and therefore the air that goes to the port, reducing bass. On the other hand, midrange and high frequencies absorbed from noise in the cabinet that don't go out through the woofer cone can upset the frequency response and make the speaker sound bright and lean, isn't it?

In other words, absorbing noise from the interior may be beneficial but if the designer didn't put dampening there might mean that he tuned that reflected sound as part of the response of the speaker.

 

[test1223]

How does the bassreflex port work, by amplifying (resonating) internal sound waves within its bandwith,

Yes almost this. It transmit sound with the fitting bandwidth trough a resonating air volume to the outside. Nothing get's amplified. It uses some energy from the back of the driver which in a closed box is not used at all.

or just by air pressure exiting the port? (it looks as it works by pumping air out)

Yes. There is no or. The air inside the tube (bass reflex port) is resonating when air pressure with the right bandwidth is present at the bass reflex port opening inside the box. The air pressure at the port opening is dependent on a few parameters.
One important parameter is the volume of the box since it changes the stiffness of the resulting spring of the driver and therefore the sound pressure the driver delivers. The other important factor is the amount of damping material inside the box, which lowers the air pressure at the bass reflex port opening, also the position of the bass reflex port opening and position of the damping material plays an important roll.

But isn't resonance frequency (caused by standing waves) dependent on cabinet internal measurements (that coincide with its wavelength) and not its mass?

There is a normal mode of the airborne sound inside the cabinet and there is a normal mode of the enclosure movement aka vibration or aka structural sound.
Both are not directly dependent form another.
The sound in the air can be seen as a standing wave where the enclosure walls reflect the sound in a way that there is a lot of sound energy inside the enclosure at certain frequencies. https://en.wikipedia.org/wiki/Standing_wave
The vibration or structural sound is caused by the airborne sound inside the cabinet which excites the walls and the moving parts of the drivers which are coupled with the enclosure (Newtons third law action = reaction).

The Elac DBR62 already features an internal bracing in a H-shaped middle wall. So bitumen pads may work well then, absorbing wall resonances and letting bass reflect into the port.

That is good but more is better and is very likely to be much superior compared with bitumen padding alone. Have a look at complex matrix bracing efforts of high end speakers.

Other weak point of typical cheap speakers is the plastic mounting plate of the terminal and tweeter, which transmits sound to the outside due to thin plastic walls. the reflected sound inside the cabinet which gets out through the cone of the driver and the bass reflex port.

My question is: since dampening material only absorbs sound from the woofer (because the tweeter is enclosed), can't we unbalance the response of the speaker tuned by the designer? I mean, on one hand, material like felt or polyfill reduce the airflow of the cabinet, and therefore the air that goes to the port, reducing bass. On the other hand, midrange and high frequencies absorbed from noise in the cabinet that don't go out through the woofer cone can upset the frequency response and make the speaker sound bright and lean, isn't it?

Yes you can unbalance the tonality. You especially have to be aware to not kill the bass reflex effect, which can easily done by placing to much damping material inside the cabinet or in the wrong spots. Some before after measurements are very beneficial to catch a potential error. The other effect which you describe are there but will not be that important but can also be perceived by a slight tonal shift.

In other words, absorbing noise from the interior may be beneficial but if the designer didn't put dampening there might mean that he tuned that reflected sound as part of the response of the speaker.

Yes the designer tuned the whole speaker as it is, but in these low price ranges the speaker designer can't apply as much bracing and complex damping strategies as he likes since the manual labor to mount a loudspeaker box must be as low as possible to get the low price.
So a cheap speaker like this Elac might benefit a lot from such tuning methods. The bass reflex function should be ensured. If the tonality is none of the less shifted to much you can try to compensate that with an equalizer, which is none of the less very important to get a good bass response, since no standard living room will provide a good bass response without an equalizer. Getting rid of resonances is one of the most important improvement of a loudspeaker and most cheap enclosures aren't ideal at all.

 

[wyup]

You especially have to be aware to not kill the bass reflex effect, which can easily done by placing to much damping material inside the cabinet or in the wrong spots. the bass reflex function should be ensured.

Okay, then how do you suggest I should properly apply damping to this speaker: bitumen pads on sides, upper and lower wall, and front and back H-bracing. Felt and polyfill sheets over bitumen except right behind the woofer, so bass port resonance frequency bandwith waves can reflect to the bass port slot without absorption?

Does the bass port bandwith coincide with the standing waves of the normal mode of the cabinet depth or is it independent? You suggest the internal bracing at the middle doubles the resonant frequency above the woofer response, but there must be still some degree of fundamental standing wave from the cabinet depth.

 

[test1223]

These blue matrix O like like bracing as good as you can fit them inside the enclosure and you are willing to break your hands while mounting through the bass hole. The area of unbraced wall parts should be as small as possible if you reduce bracing follow this rule where to brace.
The bracing behind the woofer should almost reach the magnet of the woofer and the last bit a rubber like material can be used to couple the magnet with the enclosure.

A small wood enclosure for the tweeter for the terminal /crossover can also help.

In the red areas more sound absorption material can be placed.

Bitumen and a small layer of sound absorption material can be placed on all walls with the exception around the bass reflex port opening.
Bitumen isn't that important.

 

[wyup]

Bitumen and a small layer of sound absorption material can be placed on all walls with the exception around the bass reflex port opening.
Bitumen isn't that important.

But bitumen isn't the most important thing to absorb cabinet resonances? Damping does only so much by absorbing sound energy and air pressure (which reduces cabinet noise reflection but also bass that goes to the port). Bitumen doesn't absorb airborne sound much, it rather absorbs cabinet vibration.
Bitumen on DBR62 lower wall, which is the bass reflex port should fully resonate with bass, so no pads on it? Or is the resonating wall the slot's interior one?

What causes resonance on cabinet walls to begin with, standing waves from height, depth and width wavelengths and/or wall's own resonance frequency as you pointed out earlier?

Excuse for making so many questions but it may be worth to better understand acoustics.

I recently read a post by Andrew himself about how it's most efficient when damping resonances to put the damping material in the center of the speaker because the boundary condition at the cabinet walls means the waves have zero velocity there and so are not efficiently absorbed by batting-type damping materials.

What about this, crossing the middle of the depth's length with damping? I don't understand about soundwaves having zero velocity on boundaries, doesn't a soundwave vibrate all along its own wavelength? The waveform isn't static. I've also read that "airspeeds are the highest at the middle of the box, so that's where you want the fibrous materials". But i don't get it, if the soundwave vibrates all along, why is there more 'energy' at the middle? Doesn't a soundwave propagate like shaking a string from the edge?

P.S: I remember long ago walking on an anechoic chamber where a big woofer speaker played a very low frequency sound that I didn't hear, but feel in my head only in a precise spot in the chamber, coinciding with some peak/valley part of the wave. Maybe it does have to do with the middle of the cabinet bearing more energy.. but doesn't the middle of the soundwave coincide with a 'flat' point?

And wouldn't middle crossing material absorb most air pressure to the port? You better leave a free flowing air opening to the port, wouldn't you?

 

[cavedriver]

What about this, crossing the middle of the depth's length with damping? I don't understand about soundwaves having zero velocity on boundaries, doesn't a soundwave vibrate all along its own wavelength? The waveform isn't static. I've also read that "airspeeds are the highest at the middle of the box, so that's where you want the fibrous materials". But i don't get it, if the soundwave vibrates all along, why is there more 'energy' at the middle?

And wouldn't middle crossing material absorb most air pressure to the port? You better leave a free flowing air opening to the port, wouldn't you?

boundary conditions are a fluid properties term. The air is a fluid. The air can't have any velocity at the wall because the wall is solid. The air would have to "push through it" in order to be carrying sound still when it reaches the wall. In a sense the air that is touching the wall has "stopped", but only the very last molecules right at the wall. Sound essentially comes in and bounces off, but right at the wall it has come to a stop. Out in the middle, where there are no walls around, it's travelling at it's full speed. That's the simplified version. The hard part is figuring out the behavior between the center of the box and the air really close to the walls but not right at the walls. it depends on things like the air temperature, altitude, and the shapes, densities, and flexibilities of all the other surfaces near the walls, aka stuffing. This is a problem I don't know the solution to but most audio engineers like Andrew Jones that I quoted would know. What he said makes sense to me, although I suspect that you don't have to have the stuffing very far from the walls to get most of the effect, like maybe anything more than a couple inches from the wall, depending on a bunch of things like the frequencies the cabinet walls would natural resonate at.

Regarding the port question, yes, you don't want to block the port with stuffing, but I'm not sure what distance away from the port needs to be kept clear, maybe at least a distance equal to twice the port diameter but I'm just guessing.

 

[test1223]

But bitumen isn't the most important thing to absorb cabinet resonances?

Yes there isn't anything you can simply glue on the surface of a box wall which effectively prevents the occurrence and travel of structural sound inside the cabinet walls. You have to go the box in a box way with some high acoustic resistance in between the two boxes to be very effective. With bitumen in such a cabinet the major effect is that it shifts the resonances down. For very thin walls it reduces the high frequency waves. But the cabinet walls aren't that thin.

Bitumen on DBR62 lower wall, which is the bass reflex port should fully resonate with bass, so no pads on it? Or is the resonating wall the slot's interior one?

No bitumen but bracing at the interior wall. You can't do much for the exterior wall of the slot without making the bottom of the cabinet ugly looking.

Regarding the port question, yes, you don't want to block the port with stuffing, but I'm not sure what distance away from the port needs to be kept clear, maybe at least a distance equal to twice the port diameter but I'm just guessing.

Yes, no absorption material about 5cm around the port.

 

[wyup]

Out in the middle, where there are no walls around, it's travelling at it's full speed

But doesn't sound travel at the same speed in the air? The soundwave cannot stop and accelerate. Maybe we're talking air pressure, which is how the soundwaves manifest?

With bitumen in such a cabinet the major effect is that it shifts the resonances down. For very thin walls it reduces the high frequency waves.

But its main function is absorbing the resonances.. you put bitumen on car floor or under the kitchen sink and it absorbs resonance. It does not only shift the wall's resonance frequency, it absorbs its consequence, vibration.
However, I feel that the cabinet vibration or resonance is not as important as the standing waves and and the noise itself inside the cabinet, which we want to absorb.

 

[test1223]

But its main function is absorbing the resonances.. you put bitumen on car floor or under the kitchen sink and it absorbs resonance. It does not only shift wall's resonance frequency, it absorbs its consequence, vibration.

It doesn't work good at lower frequencies. You get a lower bumb sound and the higher rattle sounds are gone. But these higher rattle sounds aren't a problem with speaker cabinets. The mechanics of thin plates and thicker plates aren't exactly the same. You have not only bending waves with thicker material you also got other types of structural sound waves.

But doesn't sound travel at the same speed in the air? The soundwave cannot stop and accelerate. Maybe we're talking air pressure, which is how the soundwaves manifest?

The sound wave is air pressure which causes uniform air movement which causes air pressure again. The absorption material works best where you have the highest uniform air movement. In the middle of the cabinet you have the highest air movement of a lot of frequencies. This is due to the reflections of the cabinet walls. The reflections transforms uniform movement into pressure.

 

[Mossshine]

Required output power is often overestimated.

I'd suggest you give the WiiM Amp a try.
If it's powerful enough for your needs, then it's the best deal you can get at the moment

There's bass management, Parametric EQ, HDMI CEC, and even automatic room correction in a future firmware update.

Nothing else even comes close.

If you get the WiiM Amp and it just doesn't get loud enough for you, then simply return it.

I know this thread is about DBR62, but I have to say, the WiiM Amp is amazing. TV, record player, phone, all connected to it. Input is being switched automatically, so its a breeze going from one device to another.

Paired with DBR62s it's more than powerful to drive them as you said. Volume is around 50% and I am already getting worried neighbours will knock on my front door to shut it up.

DBR62s definitely feel to me to be made for everything but electronic music.

Also this combo seems to be pretty sensitive to the input quality. Stream random mp3 or youtube song, I have to apply EQ to hide the flaws. On the other hand, streaming CD quality flacs or great Bandcamp hi-res songs and it's entirely different beast.

My record player is amazing with default settings without any EQ.

I have yet to try movies since I am stuck playing my whole collection. I have not had this fun in a while. Shame that I also hear my wallet screaming at me for this.

 

[Splainder]

Thinking to upgrade my Zensor 1 and Im between Elac debut reference or the uni-fi 2.0 UB52

Wondering if my Onkyo 9010 can move this speakers without any problem?

​

 

[ninetylol]

Thinking to upgrade my Zensor 1 and Im between Elac debut reference or the uni-fi 2.0 UB52

Wondering if my Onkyo 9010 can move this speakers without any problem?

​

Yes I used a 9010 with the DBR62, works great.

 

[wyup]

Thinking to upgrade my Zensor 1 and Im between Elac debut reference or the uni-fi 2.0 UB52

Wondering if my Onkyo 9010 can move this speakers without any problem?

​

I'm also using your Onkyo 9010 with the DBR62, sounds good. Bass is adequate.

 

[wyup]

Could anyone come up with the crossover schematics for this speaker? I think it deserves it for its great sound quality.

I'm curious to know how do the 67uf, 48uf and 220uF electrolytic caps for the woofer, 2.8uF film cap for the tweeter and 1.8 and 3.6 ohm resistors fit in the circuit, as well as four unknown value air core inductors. As for the high value 220uF capacitor, I haven't seen such a high value on another crossover.

 

[hipoagu]

Hello,
New here and new to hifi.. i am reading and watching a lots of reviews.
Is marantz pm6007 a good amp to drive the Elac Debut Reference dbr62 or it may lack power? I am thinking of going for that set (plus wimm mini). I currently have an old Sony lbt-d705 set (amp is ta-d705, speakers Sony ss-a705, 3-way)
The new set tp replace old Sony would run in a 20-25m2 room, not partying, just music and movies.
Thanks

 

[cavedriver]

Hello,
New here and new to hifi.. i am reading and watching a lots of reviews.
Is marantz pm6007 a good amp to drive the Elac Debut Reference dbr62 or it may lack power? I am thinking of going for that set (plus wimm mini). I currently have an old Sony lbt-d705 set (amp is ta-d705, speakers Sony ss-a705, 3-way)
The new set tp replace old Sony would run in a 20-25m2 room, not partying, just music and movies.
Thanks

only 45/60 wpc for $700? looks to be overpriced for what it is. 83 dB SNR? Ok, but not great. Most better 10 year old Denon receivers for <$200 would be better. Your Sony is probably better, but not by much (60 wpc apparently). The DBR62's are not inefficient but they are only 86 dB/w and they do love power. Andrew Jones knows how to make speakers that rock and you can crank the DBR62's pretty well. I was powering the pair I tested with a 200 wpc Hypex amp and while I wasn't about to max out the amp and damage the speakers, I would think at least 100 wpc would give you enough clean headroom for that space. Note that the Hypex amp was $700, but is just an amp and not an integrated amp. Besides the obvious choice of a vintage receiver you should be able to find an integrated amp with more power for $700. If you want something newer these Denon units can be had used for less than $700, although I don't see as many as the older ones. Just scan through the reviews of receivers (AVR's), integrated amps and small amps here on ASR and you'll find plenty of more powerful solutions. Could buy something like a small Fosi amp and use a separate DAC as an input switcher/preamp. I'm using a Minidsp on the Hypex but was using an SMSL dac for a while.

Denon AVR-X3600H AV Receiver Review

This is a review and detailed measurements of the Denon AVR-X3600H 9.2 channel AVR. It was purchased new by a kind member who drop shipped it to me. It costs US $1,099. From outside the AVR-X3600H seems like any other AVR: But the controls feel a lot better than some other AVRs. The...

www.audiosciencereview.com

 

[hipoagu]

only 45/60 wpc for $700? looks to be overpriced for what it is. 83 dB SNR? Ok, but not great. Most better 10 year old Denon receivers for <$200 would be better. Your Sony is probably better, but not by much (60 wpc apparently). The DBR62's are not inefficient but they are only 86 dB/w and they do love power. Andrew Jones knows how to make speakers that rock and you can crank the DBR62's pretty well. I was powering the pair I tested with a 200 wpc Hypex amp and while I wasn't about to max out the amp and damage the speakers, I would think at least 100 wpc would give you enough clean headroom for that space. Note that the Hypex amp was $700, but is just an amp and not an integrated amp. Besides the obvious choice of a vintage receiver you should be able to find an integrated amp with more power for $700. If you want something newer these Denon units can be had used for less than $700, although I don't see as many as the older ones. Just scan through the reviews of receivers (AVR's), integrated amps and small amps here on ASR and you'll find plenty of more powerful solutions. Could buy something like a small Fosi amp and use a separate DAC as an input switcher/preamp. I'm using a Minidsp on the Hypex but was using an SMSL dac for a while.

Denon AVR-X3600H AV Receiver Review

This is a review and detailed measurements of the Denon AVR-X3600H 9.2 channel AVR. It was purchased new by a kind member who drop shipped it to me. It costs US $1,099. From outside the AVR-X3600H seems like any other AVR: But the controls feel a lot better than some other AVRs. The...

www.audiosciencereview.com

Thanks for the anwser!
The pm6007 was awarded as best entry level integrated amp by whathifi, that's why it is in my shortlist. It is around 430€-480€, I also liked it has 2 optical inputs, i plan to use one for TV and other for Wiim streamer, mini probably. My old Sony has not digital inputs, but it is right that has more power (60w@6ohm) than the pm6007, I just wondered if pm6007 can move and squeeze all out of Elac dbr62 with those 45w@8ohm and 60w@4ohm. I assumed audio quality (plus digital inputs processing) would be an step forward compared to my Sony, even if rated slightly less power capable.
Was considering other speakers like q 3030i and wharfedale diamond 12.2, but frontal port of Elacs is quite interesting as i won't be able to place speakers far from back wall, maybe 20-30cm maximum separation.

Regards

 

[ZolaIII]

Thanks for the anwser!
The pm6007 was awarded as best entry level integrated amp by whathifi, that's why it is in my shortlist. It is around 430€-480€, I also liked it has 2 optical inputs, i plan to use one for TV and other for Wiim streamer, mini probably. My old Sony has not digital inputs, but it is right that has more power (60w@6ohm) than the pm6007, I just wondered if pm6007 can move and squeeze all out of Elac dbr62 with those 45w@8ohm and 60w@4ohm. I assumed audio quality (plus digital inputs processing) would be an step forward compared to my Sony, even if rated slightly less power capable.
Was considering other speakers like q 3030i and wharfedale diamond 12.2, but frontal port of Elacs is quite interesting as i won't be able to place speakers far from back wall, maybe 20-30cm maximum separation.

Regards

We call them what-a-hell. Stay on DBR62's and try with Yamaha A-S 501 or Yamaha A-S 701/801. If you can find second hand not used much A-S/R-S 700 even better. Also try to find old stock of R-N 803/803D.

 

[Beershaun]

Thanks for the anwser!
The pm6007 was awarded as best entry level integrated amp by whathifi, that's why it is in my shortlist. It is around 430€-480€, I also liked it has 2 optical inputs, i plan to use one for TV and other for Wiim streamer, mini probably. My old Sony has not digital inputs, but it is right that has more power (60w@6ohm) than the pm6007, I just wondered if pm6007 can move and squeeze all out of Elac dbr62 with those 45w@8ohm and 60w@4ohm. I assumed audio quality (plus digital inputs processing) would be an step forward compared to my Sony, even if rated slightly less power capable.
Was considering other speakers like q 3030i and wharfedale diamond 12.2, but frontal port of Elacs is quite interesting as i won't be able to place speakers far from back wall, maybe 20-30cm maximum separation.

Regards

At that price point just get the Wiim amp and be done. It has eARC for your TV in, you then get more power and subwoofer out for the future when you want to add a sub.