Crescendo: Eureka! 100db from a 30L Cabinet - 65hz to 25khz

[bcherry]

Why does the edge of the horn block part of the cone?

• First, the cone remains unobstructed. Only the surround is covered. Second, as the crossover frequency is at 600Hz the wavelength of the sound is around 57cm. Any obstruction that is much smaller than 1/4 of this essentially has no impact. The key is the distance between the horn acoustic center and that of the woofer. Due to the large size of both items the distance becomes quite large and approaches around halve the wavelength, so it needs to be minimised as much as possible to ensure correct integration between the drivers.

Given the nice chamfering around the main driver assembly, how does this 'lip' affect the sound?

• Not at all. The chamfering both around the driver cutout and on the edges has no sonic impact whatsoever. With only 18mm radius chamfering it only has any impact above around 5KHz, as has the overlap.

How critical is the distance between the drivers?

• The crossover would require re-design if the distance is significantly altered.

can the drivers be successfully pushed a little further apart to overcome this interference?

• They cannot be pushed further apart, but then again, there is no interference to overcome, so there is no need to.

[Studley]

Brian
Have you read Earl Geddes' theories about using 3 subs? Feedback from users is universely very favourable. It strikes me that your new speakers would make great candidates for the main speakers in such a set up. If I didn't already have a pair of Earl's Abbey front baffles on order I would seriously consider going that route.

[bcherry]

Originally Posted by Studley

Brian
Have you read Earl Geddes' theories about using 3 subs? Feedback from users is universely very favourable. It strikes me that your new speakers would make great candidates for the main speakers in such a set up. If I didn't already have a pair of Earl's Abbey front baffles on order I would seriously consider going that route.

Haven't, but would be interesting to try. The Crescendo can work with any sub configuration.

regards
Brian

[JimU]

The DIY HiFi web site mentions that crescendo cabinets will be available, what option levels will there be? Such as pre-cut, fully assembled without finish, finished. I have no clue about making cabinets, not my idea of DIY, rather just build up electronics! Tnx, Jim

[trprowda]

Are there plans for the cabinets for this system, both with and without the subs? Estimated cost? This is a very interesting looking system. Also wondering if anyone has built it, the reactions, comparisons to known products, etc.

[rcdaniel]

Hi Brian

Crescendo looks like a really nice design - lots of design time seems to have been invested. It might be helpful if more comments were available regarding their musical presentation.

Questions, relating to in-room use:

1. You mention controlled directivity in a previous post; do the ribbon and mid-bass driver have approximately matched directivity at the crossover point.

2. Related to question 1, are you able to provide plots or other information regarding the off-axis FR / power response?

3. In my room, speakers need to be positioned close to the front wall, 1-1.5 m from side walls, ~ 2 m apart, with me sitting ~ 2 m from each speaker; could the crescendi work in this arrangement?

I wish you all the best regarding this speaker (and all your endeavours).

Kind regards
Raymond

[ThorstenL]

Hi,

Originally Posted by rcdaniel

1. You mention controlled directivity in a previous post; do the ribbon and mid-bass driver have approximately matched directivity at the crossover point.

No, the crossover point is quite low, the crossover is first order, so the directivity slowly changes from the wide dispersion at LF for the cone driver to the around 80 X 20 Degrees controlled directivity of the waveguide loaded ribbon.

This is not dissimilar to some other speakers offered as "controlled directivity".

Originally Posted by rcdaniel

2. Related to question 1, are you able to provide plots or other information regarding the off-axis FR / power response?

No plots. The Horns coverage pattern pretty much tells it for higher frquencies, below that you have an 8" cone driver.

Originally Posted by rcdaniel

3. In my room, speakers need to be positioned close to the front wall, 1-1.5 m from side walls, ~ 2 m apart, with me sitting ~ 2 m from each speaker; could the crescendi work in this arrangement?

They could. The low order crossover and low crossover point make the integration between the drivers much less critical than other horn systems, so listening distance is not so critical. This was in fact one of the big attractions of this monster sized Ribbon/Waveguide combo.

Due to the narrow vertical coverage it is important to get the listening hight right though.

Kind regards T

[rcdaniel]

Thanks Thorsten. As always, your info is most helpful.

Cheers
Raymond

[ThorstenL]

Folks,

I just found a in room, stereo pair measured response at 3m distance.



Measured via iPad, pink noise played on the system, 1/6th octave smoothing.

So ignore the highest and lowest frequencies (the iPad Mike is not very good for that), also be aware that measuring a stereo pair will create comb filtering...

The room is around 100sqm and full of shelves. This graph below is an attempt to scale the FR for an approximate comparison with the Stereophile Graphs referenced later.



The measured response compares poorly with the common 1m, single speaker, anechoic or pseudo anechoic measurements.

A good comparison would be the in room responses JA publishes for some speakers in Stereophile, however unlike my one these are spatially averaged and only one speaker, so look smoother...

The two below are respectively:

Wilson Audio MAXX (blue) and Magico Q5 (red)



Audio Note E Lexus (blue) and Voxativ Ampeggio (red)



Ciao T

[badman]

Impressive little speaker! Cool stuff, would love to hear a pair.