Sierra-2 Development Thread

[Dark Ranger]

Hey all,

Just wanted to post another tidbit about the Sierra-2. We now have (2) final prototypes complete and we just spent an hour abusing them in our sound room.

You might find this hard to believe (I was quite surprised myself), but with Boom Boom Pow running full range -- we managed to hit a very clean 108 dB measured at 12 feet (stereo pair). This was with a 150 watt amplifier. Keep in mind that this is in our extremely well damped listening room. Even at this extreme volume level, we managed to have a low volume level conversation between the 3 of us in the room and we heard each other speak with ease. This is most impressive for a pair of bookshelf speakers...

WOW!!!

I remember when you showed us Boom Boom Pow with the Horizon. That was quite impressive if I do say so myself. However, IMO this takes the cake. We've gone from a highly-capable 3-way system with high power handling to a MUCH smaller 2-way (assumed) bookshelf. Getting a clean 108 dB at 12 feet back from bookshelves in a well-damped room is a huge wow factor indeed. However, the fact that you could have a normal conversation is the biggest surprise at all. Some speakers would audibly distort at those levels. This speaks volumes (pun unintended) of the overall design and component quality.

I would love to see a video of this demonstration. Of course, I can wait until after more details are revealed since a video might give away key details too soon. Or maybe you could just keep the grills on.

Thanks for the tidbit! I cannot wait to purchase a pair.

[Mag_Neato]

Awesome Dave!

Does the prototype you abused have the new, larger port, or the original Sierra-1 port?

If it is with the larger port will those of us who do a Sierra-1/NrT upgrade with original cabinets experience lower output?

Thanks!

[markie]

Wow for sure. I' guessing this demonstrates the Sierra2 has a higher efficiency than the Sierra1 ?

I recall from long ago that the Sierra1 had the special quality that it can play at high db but not sound loud, that is, the kind of irritating loud that causes someone to say "turn that thing down!" I'm supposing the ability to have have low level conversations even when the speaker is playing at high decibels is very much related to this. I vaguely recall that the Sierra1's bamboo cabinet was a big factor in this special trait. Maybe the increased resolution both of the ribbon tweeter and the new woofer, perhaps even the larger port, enhances this property all the more?

Mark

[davef]

Wow for sure. I' guessing this demonstrates the Sierra2 has a higher efficiency than the Sierra1 ?

Hi Mark,

The Sierra-2 is about 1/2 dB less efficient than the Sierra-1. Efficiency/Sensitivity and maximum output (power handling) capabilities are in no way related to each other.

[davef]

Awesome Dave!

Does the prototype you abused have the new, larger port, or the original Sierra-1 port?

If it is with the larger port will those of us who do a Sierra-1/NrT upgrade with original cabinets experience lower output?

Thanks!

The pair of Sierra-2's we used for this test and subsequent listening are with the standard Sierra-1 cabinet (same port tube as Sierra-1). I should be more clear regarding the port tubes...

There will be (2) different vendors for Sierra-1/Sierra-2 cabinets. We will be building small batches of these cabinets at our local cabinet maker (Sierra Tower cabinet maker). These Sierra-1/Sierra-2 cabinets will use the larger diameter port tube and the finishes offered will match the Sierra Towers.

The majority of Sierra-2 cabinets will be the standard Sierra-1 cabinets from our regular cabinet maker who has been making the Sierra-1 cabinets for many years now.

the -only- difference between the two ports is the larger diameter one has slightly more output at about 40-50Hz, at about 60Hz on up there is no difference. Considering that the Sierra-2 will be about 3-4dB down at 40-50Hz, the larger diameter port tube (as compared to the standard) has no effect with regard to how loud, how detailed, or the speaker's sensitivity rating. I am unable to actually hear a difference between the two different port tubes when the speakers are being run full range.

The reason we are doing this is that the port tubes used in the Sierra-1 cabinets are not available to us here in the states (they are custom tooled for us) so we must use a different port tube for the locally built cabinets. It is the exact same port tube we use in the towers, but the overall port length is changed to perfectly match the tuning of the Sierra-1 port tube..

hope this makes sense

[SGCSG1]

The pair of Sierra-2's we used for this test and subsequent listening are with the standard Sierra-1 cabinet (same port tube as Sierra-1). I should be more clear regarding the port tubes...

There will be (2) different vendors for Sierra-1/Sierra-2 cabinets. We will be building small batches of these cabinets at our local cabinet maker (Sierra Tower cabinet maker). These Sierra-1/Sierra-2 cabinets will use the larger diameter port tube and the finishes offered will match the Sierra Towers.

The majority of Sierra-2 cabinets will be the standard Sierra-1 cabinets from our regular cabinet maker who has been making the Sierra-1 cabinets for many years now.

the -only- difference between the two ports is the larger diameter one has slightly more output at about 40-50Hz, at about 60Hz on up there is no difference. Considering that the Sierra-2 will be about 3-4dB down at 40-50Hz, the larger diameter port tube (as compared to the standard) has no effect with regard to how loud, how detailed, or the speaker's sensitivity rating. I am unable to actually hear a difference between the two different port tubes when the speakers are being run full range.

The reason we are doing this is that the port tubes used in the Sierra-1 cabinets are not available to us here in the states (they are custom tooled for us) so we must use a different port tube for the locally built cabinets. It is the exact same port tube we use in the towers, but the overall port length is changed to perfectly match the tuning of the Sierra-1 port tube..

hope this makes sense

Can you say at this time if there be an upcharge for the satin finish cabinets?

Have you finalized prices on the -2 yet?

Thanks for any info.

[markie]

Hi Mark,

The Sierra-2 is about 1/2 dB less efficient than the Sierra-1. Efficiency/Sensitivity and maximum output (power handling) capabilities are in no way related to each other.

OK, thanks David, that's good to know. So I assume from your pleasant surprise at the great power handling ability of the Sierra-2 prototype that it bests even the Sierra-1's in that regard? I wonder now how the Sierra-2 prototype compares with the Sierra-1 at *low* decibels, and if there is even a name for that kind of speaker attribute. But that is for sharing at a future time. The trail of bread crumbs is best spread out evenly.

Mark

[rkoaudio]

Hi Dave, would you be able to provide preliminary measurements for frequency response (on-axis and off-axis) along with the impedance and phase plots?

[davef]

Hi Dave, would you be able to provide preliminary measurements for frequency response (on-axis and off-axis) along with the impedance and phase plots?

I have already posted the on-axis frequency response in this thread a few pages back. Our typical suite of measurements will be posted when we "officially" introduce the new loudspeaker

[rkoaudio]

Fine ... but what about impedance curve? Would it be closer to original Sierra-1 or Tower?