What is a good compromise price/performance stereo wireless transmitter/receiver for subwoofers?

aceinc

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I have a HT system in a 15'x25' room where I thought about most everything other than getting line level signal for my sub woofers to the opposite end of the room from the sound processor. I have been using a Rocket Fish stereo transmitter receiver for 10+ years and the latency is a bit much. There have been lots of changes over the last 10 years I was hoping to pick something up which will fit my needs without breaking the bank.

I've looked around and I'm not sure whether I should be looking at Blue Tooth or some other technology. My two main goals are fidelity and reduced latency. I would also like to keep the price under $100.

What would everyone recommend?
 

Sonnie

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When I used the SVSound transmitters for over a year in my room there was zero latency with those.


They are a little over $100... but well worth it. I still have mine just in case I need them again later on.
 

aceinc

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When I used the SVSound transmitters for over a year in my room there was zero latency with those.


They are a little over $100... but well worth it. I still have mine just in case I need them again later on.
Thanks for the information. Are you the Sonnie, who was a key player at HomeTheaterShack? In the mid to late aughts I was somewhat active over there.

The SVS devices have a latency of ~25.5 ms which is about 29 additional feet when setting up the HT distances. The RocketFish I currently use is about the same. I was hoping for something with less latency.

I see Bluetooth devices, would they have better latency numbers?
 

Sonnie

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MartinLogan Focus C-18
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JTR Neosis 110HT
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JTR Neosis 210RT
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JTR Neosis 210RT
Front Height Speakers
JTR Neosis 110HT-SL
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JTR Neosis 110HT-SL
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JTR Captivator 2400 x6
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You are so right... and I now remember dealing with it when I was using my miniDSP DDRC88-BM with the dual subs. I'm not sure why, but when I first read your post... my thoughts were that you were having issues outside of the latency, that it was not working very well or something was array with it. After reading your post again, I see you mention latency. I guess I just read right over that word, which happens... kinda like my wife telling me I only heard part of what she said (I think I heard her say "honey"). Unfortunately I'm not aware of the other options and what the latency might be.

Yes... John and I had HTS and sold it to the same folks that own AVS.
 

aceinc

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You are so right... and I now remember dealing with it when I was using my miniDSP DDRC88-BM with the dual subs. I'm not sure why, but when I first read your post... my thoughts were that you were having issues outside of the latency, that it was not working very well or something was array with it. After reading your post again, I see you mention latency. I guess I just read right over that word, which happens... kinda like my wife telling me I only heard part of what she said (I think I heard her say "honey"). Unfortunately I'm not aware of the other options and what the latency might be.

Yes... John and I had HTS and sold it to the same folks that own AVS.
Part of the problem with what I have is I am never quite sure what "distance" to use for the subs. They are ~10' from the listening position. Sometimes the Auto calibration will say close to 40' sometimes in the mid 20' range. I don't really know of a good way of determining what to set it to.

Due to a number of reasons I stopped posting over at HTS. The last few times I posted, there were very few replies and they all seemed to be from the "moderator." I've posted a number of things over at Audio Circles. Recently I started a thread on tweaking a pair of Klipsch Cornwalls.

A random note,;

One thing I really need to get better at is using REW.
 

Sonnie

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RTJ 410
Center Channel Speaker
MartinLogan Focus C-18
Front Wide Speakers
JTR Neosis 110HT
Surround Speakers
JTR Neosis 210RT
Surround Back Speakers
JTR Neosis 210RT
Front Height Speakers
JTR Neosis 110HT-SL
Rear Height Speakers
JTR Neosis 110HT-SL
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JTR Captivator 2400 x6
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VTI Amp Stands for the Monoblocks
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Sony 98X90L
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Universal MX-890
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Dish Joey 4K
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Zero Surge 8R15W-1 | Salamander Synergy Equipment Stand
What I do now is take the auto-setup out of the picture for my subs. All of my subs had variable phase control, so I set each one with impulse overlays. Actually I do it in pairs due to my room being symmetrical. I have two in the rear placed at the same location on each side... two about 1/3 from the front wall on each side... those are my four for music. I get them time aligned front to back. Then align them with my fronts. For movies I do allow Dirac to add subs # 5 and 6 with its setup.

Point being... you could get them time aligned with REW, depending on what control you have over the phase.
 

aceinc

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What I do now is take the auto-setup out of the picture for my subs. All of my subs had variable phase control, so I set each one with impulse overlays. Actually I do it in pairs due to my room being symmetrical. I have two in the rear placed at the same location on each side... two about 1/3 from the front wall on each side... those are my four for music. I get them time aligned front to back. Then align them with my fronts. For movies I do allow Dirac to add subs # 5 and 6 with its setup.

Point being... you could get them time aligned with REW, depending on what control you have over the phase.
Note my comment above; "One thing I really need to get better at is using REW. " Are there instructions or a video somewhere to accomplish what you describe above?

My setup is "different" and subject to change in the near future.

Currently I have Magnepan 2.7 QRs as my fronts, sitting right next to each one I have an OB "sub" (GR Research dual 12") attached in parallel with the 2.7s running as full range from the Marantz AV7704/Emotiva XPA-1s (Gen1).I run stereo music just through this arrangement. For HT I have a 15" sealed Rythmik Audio sub attached to the Rocket Fish transceivers. I am about to pull the trigger on a Behringer NX3000D to drive a pair of 10" Dayton Titanics in separate sealed cabinets which will run off the 2nd channel of the Rocket Fish (or whatever replaces it).

The OB "subs" are about 30" off the front wall, the 15" Sub is M/L centered on the rear wall below a bay window. The 10" cabinets are sitting on the back wall about 2.5' from the side walls they are currently crossed over to a pair of Magnepan MMGs I use for rear speakers. which I run full range. My reason for switching the 10" cabinets to a separate amp and running off a "sub out" is I suspect rears do not get a lot of bass content, and it is a bit of a waste. I have also read having a number of subs can even the bass nodes throughout the room when distributed in the listening area.
 

Sonnie

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JTR Neosis 210RT
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JTR Neosis 210RT
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JTR Neosis 110HT-SL
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JTR Neosis 110HT-SL
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It's fairly straight forward... using the acoustic timing reference, measure each sub then click on Overlays in REW and choose Impulse to view.

Here is what two subs look like... and notice they are not aligned (the jagged edges in these examples is from using a full sweep, if you only use a sweep from 0-400Hz, it will smooth the line).

41133


Here they are aligned... adjust the phase on the unit closest to the mic until they line up.

41134


REW Help File Excerpt

Measuring with a timing reference
REW can make use of a timing reference when it measures, according to the setting on the measurement panel. The timing reference selection controls whether REW uses a loopback on the interface as a timing reference, or an acoustic timing reference, or no reference. Using a timing reference allows REW to eliminate the variable propagation delays within the computer and interface so that separate measurements have the same absolute timing. A Timing offset can be set that will shift the response relative to the timing reference, allowing the time of flight delay to be removed if using a loopback connection, for example. The timing offset can be set manually or from the figure calculated using the Estimate IR Delay function.

If a loopback is selected the reference channel signal must be looped back from output to input on the interface and measurements will be relative to the loopback timing. Usually this means measurements will have a time delay that corresponds to the time it takes sound to travel from the speaker being measured to the microphone, which can be removed for subsequent measurements using the Timing offset.

If an acoustic timing reference is used REW will generate a timing signal on the output that has been selected to act as the reference before it generates measurement sweeps on the channels being measured. The level of the timing reference is set relative to the measurement level using the Ref level trim control, it may need to be higher or lower depending on whether the speaker used as the timing reference is further away or closer than the speaker being measured. The timing signal is a high frequency sweep to allow accurate timing, a subwoofer cannot be used as the reference channel. Measurements will have a time delay that corresponds to the difference in their distance from the microphone compared to the distance of the reference speaker - if the reference speaker is further away the delay would be negative. The delay can be shifted using the Timing offset. When an acoustic timing reference is used individual measurements taken from the same mic position will have the same relative timing, allowing trace arithmetic to be carried out on the traces in the All SPL graph. Note that multiple sweeps cannot be used when using an acoustic timing reference.

If using a timing reference REW can calculate the delay through the system being measured relative to the reference and show it in the measurement Info panel as System Delay in milliseconds, with the equivalent distance in feet and metres shown in brackets. Any Timing offset is shown below the System Delay. For speakers the delay estimate is based on the location of the peak of the impulse response. Subwoofers have a broad peak and a delayed response due to their limited bandwidth so the delay is instead measured relative to the start of the impulse response. The start of the impulse response cannot be located as precisely as the peak, however, so delay values are less accurate for subwoofer measurements.
 

aceinc

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It's fairly straight forward... using the acoustic timing reference, measure each sub then click on Overlays in REW and choose Impulse to view.

Here is what two subs look like... and notice they are not aligned (the jagged edges in these examples is from using a full sweep, if you only use a sweep from 0-400Hz, it will smooth the line).

View attachment 41133

Here they are aligned... adjust the phase on the unit closest to the mic until they line up.

View attachment 41134

REW Help File Excerpt

I am familiar with using the timing signal, but I have never seen the graphs with the time as the X axis. I assume the Y axis is amplitude irrespective of frequency or is it something else?

Since I am using a USB microphone, I assume I cannot use loopback timing. I do not have the computer with REW in front of me, where can I find these graphs in the menus?

Also I assume you are attempting to line up the very first peak as close as possible. Do you place the microphone at the main listening position?

This brings up a bunch of questions in my mind regarding cancellations caused by differing relative distances to the various drivers when moving about the listening space, but I'm going to leave that alone and test it empirically.

Another question regarding testing with REW, I was thinking the test described in the article below might be useful, but I am not sure exactly how to do it using REW. Any pointers?

 

Sonnie

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Intel NUC w/ Roon ROCK
Universal / Blu-ray / CD Player
Panasonic UB9000 4K UHD Player (for media discs)
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RTJ 410
Center Channel Speaker
MartinLogan Focus C-18
Front Wide Speakers
JTR Neosis 110HT
Surround Speakers
JTR Neosis 210RT
Surround Back Speakers
JTR Neosis 210RT
Front Height Speakers
JTR Neosis 110HT-SL
Rear Height Speakers
JTR Neosis 110HT-SL
Subwoofers
JTR Captivator 2400 x6
Other Speakers or Equipment
VTI Amp Stands for the Monoblocks
Video Display Device
Sony 98X90L
Remote Control
Universal MX-890
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FireCube for movies and Lenova Carbon X1 for Roon
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Lifetime Roon Subscription
Tidal
qobuz
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Amazon Prime
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Dish Joey 4K
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Zero Surge 8R15W-1 | Salamander Synergy Equipment Stand
You will only be concerned with the X axis for the impulse response as far as timing goes. As far as I know the Y axis is amplitude, unless someone says differently... as I've never really paid it any attention. I use my listening position, right center of my head and ear level, and line up the first peak... or dip if you have the polarity inverted for some reason.

I am not familiar with loopback timing, so I can't comment on it. I've always used acoustic timing thru my left front speaker.

Timing is not always a necessity for some enthusiasts. I've seen quite a few use timing to fix their overall combined response. I've read where a few milliseconds difference is supposedly not noticeable. Quite frankly, I don't notice it. I've made this statement several times... when Mark Seaton was in my home several years ago, we were looking at a huge issue I was having at 30Hz with my sub response. Mark got his calculator out and started punching in room size, etc... a few minutes later he grabbed the remote, extended the distance on the front subs by 5ft and the issue was gone. He used timing to fix the response, and made the statement that the 5ft distance would not hurt anything. I never argued with him as I certainly couldn't tell anything other than the response was better in the room. I've read where others have done this very same thing... adjusted timing to fix response issues. So... I do not know how important timing of the subwoofer is... I've read some say it's not as important... while others are very adamant about getting it precise. I have not researched it to make a determination one way or another.

I have not tested using Geddes... haven't had a chance to read it or consider it at this point.
 
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