I want to completely retool my lathe arm (stereo). For the purpose of embossing, would tweeters make better speakers for this application more than the small full range speakers I have on there now?
Any suggestions will be considered and thank you muches.
Driver Selection
Moderators: piaptk, tragwag, Steve E., Aussie0zborn
Re: Driver Selection
Hi,
That's really hard to say. The acoustic frequency response of the speaker has nothing to do with its performance as a cutterhead driver. To compare any two drivers, you need to look at its BL product (how many newtons of force it can generate per amp of current), the total moving mass of driver, and its maximum power capability. Size and weight for mounting purposes and ease of coupling to the voice coil are also important. Once you have these parameters along with the added mass of your stylus, stylus holder, torque tube, and coupling members, you can determine the total system moving mass. From this you can figure how much stiffness to add to get a main resonance in the 1-2 Khz range. This will give you an idea on the drive power required to cut at various frequencies. The better driver would be the one that maximizes the cut level over the frequency spectrum within the drivers' power rating (assuming that you can throw as much power to the driver from your cutterhead amp as the head can take). I hope this is of some help.
Mark
That's really hard to say. The acoustic frequency response of the speaker has nothing to do with its performance as a cutterhead driver. To compare any two drivers, you need to look at its BL product (how many newtons of force it can generate per amp of current), the total moving mass of driver, and its maximum power capability. Size and weight for mounting purposes and ease of coupling to the voice coil are also important. Once you have these parameters along with the added mass of your stylus, stylus holder, torque tube, and coupling members, you can determine the total system moving mass. From this you can figure how much stiffness to add to get a main resonance in the 1-2 Khz range. This will give you an idea on the drive power required to cut at various frequencies. The better driver would be the one that maximizes the cut level over the frequency spectrum within the drivers' power rating (assuming that you can throw as much power to the driver from your cutterhead amp as the head can take). I hope this is of some help.
Mark
Re: Driver Selection
Yes it does help thank you. I already assumed that the specs for a speaker would NOT be the same if used as a head driver. As for stiffness in the embossing armature, that is another variable I will now add to construction LOL.
Sincerely,
Mikiness
Sincerely,
Mikiness
Re: Driver Selection
Hi,
The stiffness I'm talking about is the suspension stiffness. In a speaker, this would be the surround stiffness plus any additional from the air. This together with the moving mass, would form the speaker free air resonance. Once you couple to your stylus, you might find that additional stiffness needs to be added. For example, the CUI driver I used has a free air resonance of about 400hz. By the time I was done adding the mass of my stylus holder and coupling members, an addition 1 gram of mass was added (the driver has a moving mass of about 1 gram). So the resonance would have dropped to about 280hz. I added stiffness to the head to raise the resonance up into the 900hz range. You would like to get this as high as possible while keeping moving mass as low as possible. Otherwise, you will kill the drive sensitivity. A big tweeter/speaker with 60 watt power handling may not perform better than a smaller lower moving mass driver with less power handling. More than likely, you'll find that the extra power handling will come at the expense of increased moving mass (all of that heavier gauge copper wire adds up). It will take some thought to find the best combination.
Mark
The stiffness I'm talking about is the suspension stiffness. In a speaker, this would be the surround stiffness plus any additional from the air. This together with the moving mass, would form the speaker free air resonance. Once you couple to your stylus, you might find that additional stiffness needs to be added. For example, the CUI driver I used has a free air resonance of about 400hz. By the time I was done adding the mass of my stylus holder and coupling members, an addition 1 gram of mass was added (the driver has a moving mass of about 1 gram). So the resonance would have dropped to about 280hz. I added stiffness to the head to raise the resonance up into the 900hz range. You would like to get this as high as possible while keeping moving mass as low as possible. Otherwise, you will kill the drive sensitivity. A big tweeter/speaker with 60 watt power handling may not perform better than a smaller lower moving mass driver with less power handling. More than likely, you'll find that the extra power handling will come at the expense of increased moving mass (all of that heavier gauge copper wire adds up). It will take some thought to find the best combination.
Mark