Bubbler CD 8 - options for improving the bass?

[palacekeeper]

I recently bought a Bubbler CD 8 jukebox with the optional GX5 amplifier, and everything works well overall. The one thing I would like to do, though, is increase the bass some, as it is a bit lacking imho. No issues with the power/volume. 

The amp has 2 options. You can use channel 1 for subwoofer low frequency sound only, and channel 2 for full range, OR you can use both channels with full range. The jukebox came wired from the factory and with the amp slider switch set up for option 2. Because of this, I'm thinking that the subwoofer is getting the full range input instead of just the low range in this configuration.

I don't really have a need to hook up external speakers to it, and in its current state it has the 2nd channel set up for that. 

I have 2 questions on this:

1. Has anyone rewired this model so that channel 1 is sub and channel 2 is the other internal speakers? It's a simple toggle switch on the amp to use this mode, but I'm pretty sure I'd need to rewire it to separate the sub and mid-range/tweeters. If so, how difficult was the rewiring process? Did you have to cut wires or just move some terminals around?

2. Has anyone connected Sonos to this model (or a similar model)? I would consider that option, but I'm pretty sure the delay would be unacceptable, even at the minimum Sonos delay setting of 75ms. 

Any thoughts and tips are appreciated!

Thanks!

[jukenorman]

Isn't that a current model? In which case, wouldn't it be an idea to engage with with the manufacturer on this? The CD-8 advertising blurb claims it operates with Sonos!

Norman.

[palacekeeper]

Yes, it is new, and I did talk with their service department. They said that they have had other customers inquire about wiring it with the first channel for a sub, but did not have the details on how it was done.

As far as Sonos, the guy I spoke with at Rock-Ola was unsure about any sound delays. I also talked with Sonos and they said that most likely there would be some delay. The delay is no big deal if you are only using wireless speakers, but is a problem if the wired speakers inside the unit are getting the sound out much quicker and both sets are playing at the same time.  It would probably also depend upon the distances, Wifi performance and other factors.

I got the impression that the capability is advertised because it has terminals on the back for standard speaker wires that come off the second channel, so yeah, any type of secondary speakers could be added, potentially.

Just wondering if anyone has gone down the road of wiring it differently for the sub on channel one, mainly. The bass is not bad, but with a 500 watt amp that has the capability to isolate one channel for the sub, it just seems like I'm missing out on better bass if it were wired that way. I'm considering trying it but wanted to see if anyone else had done it and had any lessons learned, recommendations, etc.

The Sonos was another thought, but was mainly for exploring workarounds. 

Thanks!
Jim

[jukenorman]

Well, silly me for thinking that the manufacturer would help you! Did you get any documentation, maybe a diagram of how the amplifier is configured v/v the loudspeakers? I had a quick look at the website but as far as I can see there is no documentation available to download.

Norman.

[palacekeeper]

Thanks Norman. I did find schematics in the back of the manual, but I didn't see one specific to the speakers and how they are wired.

The user manual for the amp is located here (I'm new to this forum but didn't see a way to attach the PDF file): www.qsc.com/resource-files/productresources/amp/gx/q_amp_gx_usermanual.pdf

From what I can tell, they have both channels going to all speakers, but I'm not certain.


I also had another idea to throw out there for consideration that might be a whole lot easier and less likely to cause cabinet vibration, too. I could explore hooking up an external subwoofer to the speaker outputs on the back. I borrowed one from another system in the house and it does work, although it is super sensitive to volume increase. This is where I am out of my element. I'm guessing it was because the subwoofer I tested with was powered, so it was getting power from both sources.

1. I don't have one to test with, but I'm assuming that I should really be using a passive subwoofer since the speaker terminals are already powered and coming from the amplifier inside the jukebox. Is that correct, or would I still need a powered subwoofer?

2. I experimented with swapping the inputs and outputs and toggling the switch to set channel 1 to low frequency. It was hard to tell, really, whether there was any real difference, other than a lower overall sound when the switch was set to low frequency mode. My thought was that maybe if I just swap the outputs from the amplifier so that the output to the external speakers was on channel 1 instead of channel 2, that I could then use the low frequency switch (which only has that option on channel 1). Again though, hard to tell and it may be because everything is wired to all speakers.

If I can figure out how to attach pics of how the amp looks inside of the cabinet (other than from a URL), I'll add those too :-)

Thanks!
Jim

[jukenorman]

Hi Jim,
First of all, I need to say that I've never seen or heard a CD8, but I'm surprised by the perceived lack of bass because that's not normally something that you find with jukeboxes! I've done a little bit of digging on your behalf though. I do have a 2003 CD8 manual that I saved years ago (and forgotten I had) probably when there was a previous query. The amplifier is a different type but I'm assuming that the speaker configuration is the same or at least very similar.

I can probably now understand why Rock-Ola were less than helpful because it appears that what they have done is taken a QSC amp and connected it as stereo in the CD8. The option to split the channels and use one to power a subwoofer is peculiar to the amp and something that R-O possibly won't have considered or catered for. Basically what you are proposing is a redesign of the CD8 sound system.

The CD8 (as set out in my manual) speaker configuration is a dual voice coil woofer, two midrange and two tweeters connected as stereo via a crossover network. Adjusting the crossover components might be an option to consider? Adding an additional sub woofer (dual coil) is a also possibility although my gut feeling is that it seems extreme (maybe too bassy?) and no, it wouldn't require to be powered. Although as a further thought, a small active sub woofer might be the best option because you would then have full control of its output and be able to adjust it to suit your exact requirements.

Norman.

[palacekeeper]

Thanks, Norman, for the additional information on this. I really appreciate your taking the time! Here are my thoughts on your points:

"First of all, I need to say that I've never seen or heard a CD8, but I'm surprised by the perceived lack of bass because that's not normally something that you find with jukeboxes! I've done a little bit of digging on your behalf though. I do have a 2003 CD8 manual that I saved years ago (and forgotten I had) probably when there was a previous query. The amplifier is a different type but I'm assuming that the speaker configuration is the same or at least very similar."


        The "lack" of bass is probably an exaggeration in comparison to what many people might expect. To be fair, I'm new to the world of jukeboxes, and my audio experiences are more aligned with traditional receivers and full room audio as well as home theater setups. The bass         capabilities in those configurations are substantial, and when I fire up one of those receivers to listen to music, I'm used to plenty of bass, and adjust it according to the acoustics of the room. For a jukebox, I have to consider the cabinet and vibrations. R-O did say that they tune the         sound at the factory for optimal performance. I would have to assume that means that they don't want to ship a jukebox where the cabinet and glass vibrate. Also, the volume capability of the jukebox is quite impressive and doesn't distort or vibrate the cabinet - even at very high         volumes. So, I guess what I'm saying is that the sound is probably what it is supposed to be, considering the design. 

"I can probably now understand why Rock-Ola were less than helpful because it appears that what they have done is taken a QSC amp and connected it as stereo in the CD8. The option to split the channels and use one to power a subwoofer is peculiar to the amp and something that R-O possibly won't have considered or catered for. Basically, what you are proposing is a redesign of the CD8 sound system."


        If you can tell me what page(s) you are referring to in the 2003 manual, I could send you the updated versions by creating a PDF of those pages (if you're interested in seeing the updated versions).


"The CD8 (as set out in my manual) speaker configuration is a dual voice coil woofer, two midrange and two tweeters connected as stereo via a crossover network. Adjusting the crossover components might be an option to consider?"

        The system came from the factory with the bass at maximum in the equalizer settings. Is that what you are referring to?


"Adding an additional sub-woofer (dual coil) is a also possibility although my gut feeling is that it seems extreme (maybe too bassy?) and no, it wouldn't require to be powered. Although as a further thought, a small active sub woofer might be the best option because you would then have full control of its output and be able to adjust it to suit your exact requirements."

        When I tested out the powered subwoofer from one of my home theater systems, you are correct in that the effect was a bit extreme, and I had to turn down the gain to tweak it. That being said, with just a bit more bass provided by the subwoofer the whole setup sounded fantastic,         with the added advantage of a subwoofer outside of the cabinet that is adjustable and won't vibrate the cabinet or glass of the jukebox (assuming reasonable volume levels, of course).

        I'm looking into a few options for a small, powered subwoofer that I can position behind a club chair nearby. I think this will end up being the tweak I'm looking for - not to mention far less complicated and risky than messing with the wiring of a brand new and expensive jukebox!


Again - I really appreciate your time and insights on this!
Jim


    

[jukenorman]

Hi Jim,
I think you may have misunderstood what I was trying to say. Rock-Ola have installed a QSC amplifier in your CD8 and it is configured as two separate channels feeding two separate speaker channels via two crossover networks - what we would normally term conventional stereo. The woofer in your CD8 has two voice coils so it receives output from each channel; you also have a mid range and tweeter per channel so the two audio channels are identical

An option that is available on the amplifier is to use one channel to power a sub woofer. When you do that, one channel is outputing frequencies below 100Hz (to sub woofer only) and the other channel is outputing frequencies above 100Hz (to full range speaker(s)). The input signal is now fed to channel one only along with a jumper to the second channel making the system mono. What I was suggesting is that Rock-Ola have not considered that mode of operation (it's quite different) and if you go down that route, you would be undertaking a redesign of the audio system. In the simple terms though, maybe the only real advantage it would give would be the ability to adjust channel gain independently but there might be concerns about performance just above 100Hz - as I said it's a redesign.

In the 2003 manual, there is a diagram of the crossover so I was able to figure out how the speakers were wired in conjunction with the parts list. My assumption is that the current system of loudspeakers is the same or very similar because the same number of speakers are used, the advertising blurb tells us that.

I also have to say that I'm suprised that the bass was set to maximum on the equalizer settings as you received it from the factory, that doesn't strike me as what you would expect from a well designed system!

Norman.

[palacekeeper]

Thanks Norman, all that makes sense. It also reinforces why attempting to change the way it's set up is not a good idea. I went ahead and ordered a small powered sub. Seems like the best option overall and allows me to tweak the bass.

As far as how the EQ was set from the factory, I can only guess that maybe it's because the bass is a bit lacking. It's borderline acceptable imho with the bass set that way, but by adding a bit more it sounds really great! I am 100% certain that the EQ was set that way from the factory because I took a picture of the EQ settings with my phone before I messed with any settings.

Thanks for all the information on this. I definitely learned a lot :-)