Sierra-2 Development Thread

[Dark Ranger]

Wow, that's remarkable! I don't recall ever seeing a virtually flat plane for impedance. In fact, I don't think I've ever seen a bode plot quite like that. I also like how it doesn't rise sharply as frequency increases (like an exponential curve). The folks using receivers should be thrilled with this news. Yup, the Sierra-2 is turning out to be pretty special.

Thanks for sharing!

[Mag_Neato]

Honestly, I haven't really given this much thought but it certainly would not be too difficult to throw either the NrT dome or the stock Sierra-1 dome in the Sierra-2 and develop a matching crossover. However, this would mostly just be a Sierra-1 / Sierra-1 NrT, which are already quite popular.

Hmm, I noticed that Dave did not refute the comment about a RAAL tweeter being used in the Sierra-2. Could this be a giveaway, or simply Dave's attempt to misdirect us? Staying tuned to this channel!!

[eliwankenobi]

I remember Dave speaking about sonething he found on the RAAL that after some tweaks would give a better result or the same result and cost less. Perhaps that pertains to the tweeter for Sierra-2? He even showed a pic of a RAAL employee working on their shop..

[RicardoJoa]

IMO, there is a good chance that it will be a raal 70-20, considering that the port for the sierra 2 is larger, allowing a shallower port length. It could be the one wihout the amorphouscore to keep cost down. I think for the sierra 1 owners, if indeed is the raal 70-20, there is a good chance that the port may need to modify to acomplish the mod. Also if inseed a new woofer is in, it will likely be a version similar to the mid driver of the towers. Just my wild guesses.

[Mag_Neato]

IMO, there is a good chance that it will be a raal 70-20, considering that the port for the sierra 2 is larger, allowing a shallower port length. It could be the one wihout the amorphouscore to keep cost down. I think for the sierra 1 owners, if indeed is the raal 70-20, there is a good chance that the port may need to modify to acomplish the mod. Also if inseed a new woofer is in, it will likely be a version similar to the mid driver of the towers. Just my wild guesses.

I respectfully disagree!

Dave went to extreme measures & cost to ensure this would be as user-friendly as possible for doing the upgrade to a standard Sierra-1/NrT. Even if the tweeter is a customized RAAL it would most definitely be designed as a drop-in replacement w/out need to modify the port tube.

Just my opinion based on Dave's reputation.

[RicardoJoa]

Disagreement taken.
Of course i hope it is something easy to do like a drop in and be done with it but at least you will still need to uscrew the old crossover and put the new one in. I certainly dont find modifying the port a dificult task. Im pretty sure if that is the case Dave will have a good instruction.
The sierra 1 port are 6.5 inches in length so that leave 3.25 inch. The overall depth of the tweeter might be to deep and in a way of the ports.

[eRob]

I respectfully disagree!

Dave went to extreme measures & cost to ensure this would be as user-friendly as possible for doing the upgrade to a standard Sierra-1/NrT. Even if the tweeter is a customized RAAL it would most definitely be designed as a drop-in replacement w/out need to modify the port tube.

Just my opinion based on Dave's reputation.

Your correct. I wonder how it will compare to the 70-20 since it would have to be a much smaller custom RAAL.

[RicardoJoa]

I respectfully disagree!

Dave went to extreme measures & cost to ensure this would be as user-friendly as possible for doing the upgrade to a standard Sierra-1/NrT. Even if the tweeter is a customized RAAL it would most definitely be designed as a drop-in replacement w/out need to modify the port tube.

Just my opinion based on Dave's reputation.

The raal 70-10 will fit fine.
Interesting that the graph Dave posted has a bump up top from 10k on. I thought that the 70-20 on the tower were flatter, so maybe after all may not be the 70-20 used in the tower. From Dave post, it is very likely a raal as he mentioned that there is only one type of tweeter that can have such linearlity frequency.

[davef]

The raal 70-10 will fit fine.

No, not without extensive cabinet modification. It is not even close.

Interesting that the graph Dave posted has a bump up top from 10k on. I thought that the 70-20 on the tower were flatter, so maybe after all may not be the 70-20 used in the tower. From Dave post, it is very likely a raal as he mentioned that there is only one type of tweeter that can have such linearlity frequency.

The measurement you are referring to is not what should be used to compare to our published measurements. Under the same test conditions (production line measurements as opposed to lab generated measurements) where the microphone height and loudspeaker height is fixed and not at the ideal height, our Sierra Ribbon Towers generally exhibit the same slight rise. You should not be the least bit concerned about a 1.8dB deviation from dead flat between 15kHz-20Khz, there is not a tweeter manufacturer in existence (including RAAL) that can keep to a +/- 0.9dB tolerance in this frequency range and frankly, it isn’t necessary to do so as it would dramatically drive up costs.

Ricardo, it is important to understand that when a manufacturer formally publishes measurements, they always use a completed speaker that measures the best or the closest to average. They pick the woofers, tweeters, and crossovers out of many hundreds of units (or thousands) that best represent the average, as this should result in the most accurate published measurement. You are looking at a raw measurement, where we don't yet have the ability to establish the "average" for the components used, simply because there are only 2 of each of the components used in existence.

I can assure you that when we receive all of the Sierra-2 components, and we are then able to measure several hundred and establish an average for each component, our formal measurements for publication will likely look even better. The speakers won't sound any different, as there is not a human being alive that could actually hear a deviation in the frequency range you mention.

Confusion / concern like this is one of the reasons I generally don't like to post any measurements until the final product is in production, or at least until we receive volume quantities of the components being used.

Hope this makes sense!

[FirstReflect]

I have it on good authority that the Sierra-2 definitely uses a ribbon tweeter But the exact brand and model of ribbon tweeter are still unknown to me. It is not the exact same RAAL 70-20XR as used in the Sierra Tower and Horizon, though. It is definitely a different model of ribbon tweeter.

Whatever the brand and model, it had been customized to physically fit into the exact same opening in the cabinet as the NrT or standard Sierra-1 dome tweeter.

As Dave has said outright, the cabinet, including the port, is identical to the Sierra-1. Anyone who already owns a Sierra-1 or Sierra-1 NrT can upgrade the drivers and crossover to turn that exact same cabinet into a Sierra-2!

The only reason for the mention of the larger port is because the Sierra-1 cabinets are made overseas. But Ascend also has a domestic cabinet maker. That domestic cabinet maker does not have stock or access to the regular Sierra-1 port. That port is only being made overseas. But the domestic cabinet maker DOES have access to the Sierra Tower port.

So smaller batches of Sierra-2 cabinets will be made domestically. They will use the larger Sierra Tower port, and they will have the same finish options as the Sierra Towers, meaning matte black and satin. The overseas cabinet maker will still be making the majority of Sierra-2 cabinets, which are identical to the Sierra-1 cabinets. So, same port, same finishes. It's only because the domestic cabinet maker will ALSO be making smaller batches of Sierra-2 cabinets that the whole "larger port" thing came up