Introducing the Luna Mini Monitor!

[sonicboom]

The Q-Plugs work fine with Sierra-2's -- but because the bass alignment between Sierra-1 and Sierra-2 are different, in most close proximity placements, the plugs won't be needed with the 2's...

Hi Dave,

This is interesting. In my wall-mounted set-up, the CMTs sounded muddy, even when crossed-over at 80Hz. I attribute this to the speakers' close proximity to the wall. My speaker mounts only allow about 2 inches between the port and the wall. Because of this, I am using the CBMs as my wall-mounted mains. For some reason they are not plagued by the same muddiness.

Now, I understand that the Sierra line is more bass-capable than the SE series. Please enlighten me as to why the Sierra-2 will not pose problems in close proximity placements unlike the CMTs.

Thanks, Dave.

Daniel

[jahjd2000]

Dave,

Will the sat be available with the NrT tweeter by chance? I know I could just use a Sierra-1 with NrT, but I'd prefer something in a smaller form factor that would match my Sierra Towers and Horizon (NrT).

Jason

[davef]

Hi Dave,

This is interesting. In my wall-mounted set-up, the CMTs sounded muddy, even when crossed-over at 80Hz. I attribute this to the speakers' close proximity to the wall. My speaker mounts only allow about 2 inches between the port and the wall. Because of this, I am using the CBMs as my wall-mounted mains. For some reason they are not plagued by the same muddiness.

Now, I understand that the Sierra line is more bass-capable than the SE series. Please enlighten me as to why the Sierra-2 will not pose problems in close proximity placements unlike the CMTs.

Thanks, Dave.

Daniel

Daniel,

I am not sure how the 340's entered into the discussion when comparing the bass response of the Sierra-1 and Sierra-2, but I will address your question.

First off, there is a great misunderstanding in the general public regarding rear ported speakers and the clearance behind them. Most people seem to think that clearance is needed because the output of the port fires directly into the wall behind the port and then bounces off causing things to sound muddy when the port is too close.

Clearance behind the port is needed so as to not hinder the airflow in and out of the port. Hindering the airflow will change (lower) the port tune frequency which would typically result in changing the low frequency response by lowering the -3dB point but with less output above this point. As a rule of thumb, it is recommended to provide enough clearance behind the rear port that is equal to the diameter of the port to provide unhindered airflow.

That said, for all of our speakers, the port tune frequency is at least 2 octaves lower than the baffle step frequency such that all audible wavelengths produced by the port travel in all directions around the cabinet - not just towards the back of the speaker, but to the front as well. It would be the same if the speaker had the same bass response but was sealed, the same low frequencies produced by the front woofer would also wrap around the cabinet - not just project forward.

I can understand your assumption that the Sierra-2 would sound even muddier than the 340's in the same positioning in your room (because the Sierra-2 have deeper bass), but you really can't make this assumption. There is much more to bass response than simply how deep the speaker will go. There are all of the frequencies above that -3dB point and the energy of those frequencies is determined by the bass alignment of the speaker. For ported speakers, there are many different types of bass alignments - which is precisely why one ported speaker might have a -3dB at 40Hz and another at 60Hz, yet the speaker with -3dB at 60Hz might sound warmer or sound like it even has more bass.

The bass alignment of the Sierra-2 is tuned for the most accurate transient response, which is different than the bass alignment of the Sierra-1 and the CMT-340. So while the Sierra-2 has a lower -3dB point than the 340, the 340 is tuned differently so it will have more output at certain higher bass frequencies than the Sierra-2. It is in these upper bass frequencies (typically in the 60-110Hz range) that bass reinforcement occurs with close wall proximity (nothing to do with the rear port) such that a speaker might start to sound muddy as it gets closer to that wall.

There are additional factors as well but I hope this at least provides a general explanation.

[davef]

Dave,

Will the sat be available with the NrT tweeter by chance? I know I could just use a Sierra-1 with NrT, but I'd prefer something in a smaller form factor that would match my Sierra Towers and Horizon (NrT).

Jason

We are planning on offering all (3) tweeter options. Sierra-1 dome, NrT dome, and Sierra-2 ribbon

[eliwankenobi]

Is it official that the Sierra Sat will be rear ported?

[davef]

Is it official that the Sierra Sat will be rear ported?

No --not sure why you drew this conclusion. Currently in the lengthy process of cabinet design.

[jahjd2000]

We are planning on offering all (3) tweeter options. Sierra-1 dome, NrT dome, and Sierra-2 ribbon

Sweet! Thanks Dave.

A few more inquires. And are you able to share what the recommended x-over frequency will be for the sat? And since I have you, what is the lowest recommended x-over for the Sierra-1, again for HT use? I ask because I read a thread today describing the merits of full range surrounds. Apparently some users swear by it. I've been debating getting b-stock Sierra-1s for my surrounds (to pair with my NrT towers and Horizon) but I'm intrigued by the sat.

[eliwankenobi]

No --not sure why you drew this conclusion. Currently in the lengthy process of cabinet design.

Thanks for the reply Dave.

I wasn't sure if final cabinet design was done. Thanks for confirming that. I remember a sealed cabinet was in consideration, and btw, your comments about the Sierra-2 rear port, make me feel better about having my speakers less than a foot a away from the front wall

[sonicboom]

Daniel,

I am not sure how the 340's entered into the discussion when comparing the bass response of the Sierra-1 and Sierra-2, but I will address your question.

First off, there is a great misunderstanding in the general public regarding rear ported speakers and the clearance behind them. Most people seem to think that clearance is needed because the output of the port fires directly into the wall behind the port and then bounces off causing things to sound muddy when the port is too close.

Clearance behind the port is needed so as to not hinder the airflow in and out of the port. Hindering the airflow will change (lower) the port tune frequency which would typically result in changing the low frequency response by lowering the -3dB point but with less output above this point. As a rule of thumb, it is recommended to provide enough clearance behind the rear port that is equal to the diameter of the port to provide unhindered airflow.

That said, for all of our speakers, the port tune frequency is at least 2 octaves lower than the baffle step frequency such that all audible wavelengths produced by the port travel in all directions around the cabinet - not just towards the back of the speaker, but to the front as well. It would be the same if the speaker had the same bass response but was sealed, the same low frequencies produced by the front woofer would also wrap around the cabinet - not just project forward.

I can understand your assumption that the Sierra-2 would sound even muddier than the 340's in the same positioning in your room (because the Sierra-2 have deeper bass), but you really can't make this assumption. There is much more to bass response than simply how deep the speaker will go. There are all of the frequencies above that -3dB point and the energy of those frequencies is determined by the bass alignment of the speaker. For ported speakers, there are many different types of bass alignments - which is precisely why one ported speaker might have a -3dB at 40Hz and another at 60Hz, yet the speaker with -3dB at 60Hz might sound warmer or sound like it even has more bass.

The bass alignment of the Sierra-2 is tuned for the most accurate transient response, which is different than the bass alignment of the Sierra-1 and the CMT-340. So while the Sierra-2 has a lower -3dB point than the 340, the 340 is tuned differently so it will have more output at certain higher bass frequencies than the Sierra-2. It is in these upper bass frequencies (typically in the 60-110Hz range) that bass reinforcement occurs with close wall proximity (nothing to do with the rear port) such that a speaker might start to sound muddy as it gets closer to that wall.

There are additional factors as well but I hope this at least provides a general explanation.

Hi Dave,

Your response is deeply appreciated. I did not expect my post to get such a comprehensive answer. The way you treat forum members is an excellent expression of top notch people relations.

Thank you, sir.

Daniel

[davef]

Sweet! Thanks Dave.

A few more inquires. And are you able to share what the recommended x-over frequency will be for the sat? And since I have you, what is the lowest recommended x-over for the Sierra-1, again for HT use? I ask because I read a thread today describing the merits of full range surrounds. Apparently some users swear by it. I've been debating getting b-stock Sierra-1s for my surrounds (to pair with my NrT towers and Horizon) but I'm intrigued by the sat.

An 80Hz crossover would be ideal for the sat's, that is the design goal. Depending on the final cabinet design and port tuning (which is very complicated for this speaker - how do you fit a 10" long port in a 5" deep cabinet? lol) - it might be possible to even cross lower, 70 or even 60. Keep in mind that the deeper I tune the bass, the larger the cabinet will be and I am aiming for something at least as compact as the HTM-200 (hopefully a bit smaller).