Elac Debut Reference DBR-62 Speaker Review

[ninetylol]

I agree that andrew did a great Job and we shouldn't probably mess with it, if we dont know what we are doing.

Stuffing ports would just hurt bass performance, which wouldnt matter with a sub though.

I would only do it with before and after measurements though.

 

[ZolaIII]

I agree that andrew did a great Job and we shouldn't probably mess with it, if we dont know what we are doing.

Stuffing ports would just hurt bass performance, which wouldnt matter with a sub though.

I would only do it with before and after measurements though.

I told specialy when crossing with sub's stereo @ 120 Hz (and by hand with lot additional work by hand that it slopes very good to a model as close as you are getting by measuring and even more work on cutting the mains as foam plug ain't tame thing as close enclosure not even remotely). I agree with your first premise conclusion.

 

[cavedriver]

Why not? Isn't there a chance that the manufacturer didn't put damping inside for cost saving reasons and that some reported resonances come from the inside?

I don't agree with the other comments here- feel free to add stuffing, it's a reversible change so if it doesn't help just take it back out. 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. Andrew is active on a number of forums including occasionally here, facebook, and DIY forums so you could try to ask him. He also regularly attends shows like Axpona, CAF, and others, and is generally a very helpful person.

 

[Bleib]

Quite interesting that the German Stereo measurements look different

Red = on axis
Blue = under 30°

Stereo: Produkt

www.stereo.de

 

[wyup]

How do you toe-in these speakers?

I had them on-axis to my listening point on an equilateral triangle, but I don't get much center image.

Last week I listened to a pair of Monitor Audio Silver 200 at similar position which were ever so slightly toed-in, and imaging was much better: you get to hear music coming from the front in-between the speakers. I have tried ther same with our DBR62 and I think it improves, stereo image widens but I don't get the central image I got with the MAs.

Influenced by directivity graphs I thought speakers should face the listener not to lose linearity but I think I got it wrong.

Do any of you get a central image at a certain point between the speakers?

 

[Doenerkunde]

How do you toe-in these speakers?

I had them on-axis to my listening point on an equilateral triangle, but I don't get much center image.

Last week I listened to a pair of Monitor Audio Silver 200 at similar position which were ever so slightly toed-in, and imaging was much better: you get to hear music coming from the front in-between the speakers. I have tried ther same with our DBR62 and I think it improves, stereo image widens but I don't get the central image I got with the MAs.

Influenced by directivity graphs I thought speakers should face the listener not to lose linearity but I think I got it wrong.

Do any of you get a central image at a certain point between the speakers?

I tend to toe in all speakers "on axis" because often times I do not sit in the exact center and the center image tends not to collapse as much as it would with parallel speakers.

I generally find the center image to be pretty stable with the DBR62. More stable than with most speakers I had (the DBR62 are my first speakers with a pronounced waveguide). The flipside is that I find the soundstage to be rather compact and confined to between the speakers. It is often said that there is some kind of tradeoff: narrower directivity leads to a more stable center image, while wider directivity leads to a more plausible "speaker disappearance".

Are the tweeters of your DBR62 at ear level? I´m asking, because in the vertical off-axis there are phase cancelations in the crossover region. I try to raise the tweeters slightly above my ear with all 2 way speakers, because the cancelations are not symmetric and tend to be worse above the tweeter.

 

[wyup]

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.

How do you put dampening in the center of the DBR62? There is a flat H beam inside, I thought of padding there with bitumen adhesive.

If you stuff batting crossing in the middle with staples won't you hurt the intended acoustics?

 

[cavedriver]

How do you put dampening in the center of the DBR62? There is a flat H beam inside, I thought of padding there with bitumen adhesive.

If you stuff batting crossing in the middle with staples won't you hurt the intended acoustics? You design a internal cavity of a loudspeaker for something, don't you?

long topic that others could respond to much better than me. But consider that batting in the center would still be mostly air by volume, and so sound energy would still pass through it only with some of it's energy reduced by impact with the batting. I won't try to explain how bass reflex cabinets are supposed to work because I will screw it up. I would recommend googling it if no one responds. But I will add that bitumen is not for absorbing sound passing through air. It is a damp mass for keeping physical objects from vibrating. The ideal application is metal car doors apparently, but you can apply it to the walls of speakers to reduce the amount they resonate. But it won't absorb the resonance in the air inside the cabinet, it will just stop the walls from being energized and making their own noise.

 

[wyup]

Well, the resonances are created by vibrations on the walls caused by stationary waves, so bitumen may work well to avoid them. I am not sure internal damping is desired, because it absorbs all reflections (body) and bass reflex, as you point out.

My question is: can stationary waves exist even if walls are treated? If walls can't vibrate they can't resonate and waves can't increase amplitude, right?

 

[test1223]

Well, the resonances are created by vibrations on the walls caused by stationary waves, so bitumen may work well to avoid them. I am not sure internal damping is desired, because it absorbs all reflections (body) and bass reflex, as you point out.

My question is: can stationary waves exist even if walls are treated? If walls can't vibrate they can't resonate and waves can't increase amplitude, right?

Is a stationary wave for you a standing wave which travels through the air due to the dimensions of the cabinet? They exist as long as the walls of the cabinet reflect sound and bitumen on the wall doesn't affect these reflections in lower frequencies.

Or are you interested in the sound transmission of the cabinet, due to the sound waves inside the cabinet walls, bassreflex port and driver cone? Here materials like bitumen can help a bit in the middle to higher frequencies. Due to its ability to damp higher frequency surface waves.
But normal modes of the cabinet can shift towards lower frequencies due to the higher mass of the cabinet walls with bitumen.

Normal modes are a major part of sound transmission though the cabinet. So you can even get a overall worse behavior in some cases with bitumen.

Bracing shifts the eigenmodes towards higher frequencies and lowers the amplitude, which is the way to go in most bass cabinets.

 

[wyup]

Troels Gravesen explains how he does dampening with bitumen (optional), and mainly felt and polyester foam:

Cabinet-damping

He usually doesn't stuff the inside, but here he fills with 60gr sheep wool on top of felt. Curiously it does not seem to affect the port... or does it?

 

[Mossshine]

I would like to use these with my TV to watch movies primarily. Would someone be kind enough to recommend few amps that have reasonable price/performance and are available in EU?

 

[ninetylol]

I would like to use these with my TV to watch movies primarily. Would someone be kind enough to recommend few amps that have reasonable price/performance and are available in EU?

WiiM amp with hdmi arc

 

[Mossshine]

WiiM amp with hdmi arc

Wouldn't that be underpowered? Sorry if my question is stupid, I am not expert in this. I am just comparing the output specs, speakers use 8ohm at 120w, the WiiM can deliver 60w at that most.

 

[ninetylol]

Wouldn't that be underpowered? Sorry if my question is stupid, I am not expert in this. I am just comparing the output specs, speakers use 8ohm at 120w, the WiiM can deliver 60w at that most.

Im using the combo and with volume slider like this i get about 70-75db

I never Set it to max volume before, but I think you should be able to reach about 100db

 

[ninetylol]

Btw the speakers are rated for 120w MAX, so if WiiM amp pushes 60watt (it will do a a bit more at 6ohm) and you go from 60 to 120 you just add 3db more volume. Which is on the fence of barely noticable. So no, it's not underpowered.

 

[staticV3]

Wouldn't that be underpowered? Sorry if my question is stupid, I am not expert in this. I am just comparing the output specs, speakers use 8ohm at 120w, the WiiM can deliver 60w at that most.

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.

 

[delta76]

Wouldn't that be underpowered? Sorry if my question is stupid, I am not expert in this. I am just comparing the output specs, speakers use 8ohm at 120w, the WiiM can deliver 60w at that most.

speaker's power requirement are overestimated. the max 120w means don't try to push more than 120w to this speaker which could damage it, but in reality you would be hurting your ears before hurting the speaker. this speaker has sensitivity of 86dB/1m/2.83v, so you only need 1w to produce 86dB at 1m. 10w with 2 speaker give you 99dB at 1m, or 89dB at 3m (normal listening listen)
80dB is the reference listening level and is considered loud to most people. 89dB is generally unhealthy in longer listening session.

 

[Mossshine]

speaker's power requirement are overestimated. the max 120w means don't try to push more than 120w to this speaker which could damage it, but in reality you would be hurting your ears before hurting the speaker. this speaker has sensitivity of 86dB/1m/2.83v, so you only need 1w to produce 86dB at 1m. 10w with 2 speaker give you 99dB at 1m, or 89dB at 3m (normal listening listen)
80dB is the reference listening level and is considered loud to most people. 89dB is generally unhealthy in longer listening session.

Thank you for the detailed information

 

[wyup]

Is a stationary wave for you a standing wave which travels through the air due to the dimensions of the cabinet? They exist as long as the walls of the cabinet reflect sound and bitumen on the wall doesn't affect these reflections in lower frequencies.

Or are you interested in the sound transmission of the cabinet, due to the sound waves inside the cabinet walls, bassreflex port and driver cone? Here materials like bitumen can help a bit in the middle to higher frequencies. Due to its ability to damp higher frequency surface waves.
But normal modes of the cabinet can shift towards lower frequencies due to the higher mass of the cabinet walls with bitumen.

Normal modes are a major part of sound transmission though the cabinet. So you can even get a overall worse behavior in some cases with bitumen.

Bracing shifts the eigenmodes towards higher frequencies and lowers the amplitude, which is the way to go in most bass cabinets.

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?

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.

Can you explain a bit about eigenmodes and bracing? How can you add bracing to a finished cabinet such as the DBR62?

Thanks in advance.