Bottlehead Forum

Bottlehead Kits => Moreplay => Topic started by: Dzrout on December 27, 2022, 06:16:48 AM

Title: Moreplay Subwoofer output
Post by: Dzrout on December 27, 2022, 06:16:48 AM
How could I limit the second output on my Moreplay to only output 35hz and lower?

Or bonus points if I can put an adjustable crossover on it. But ideally, I’d love to just run the signal through a capacitor.

Thank you for your help!
Title: Re: Moreplay Subwoofer output
Post by: Paul Birkeland on December 27, 2022, 06:23:58 AM
Whether or not you can do this successfully will depend a fair amount on the input impedance of your subwoofer amplifier.
Title: Re: Moreplay Subwoofer output
Post by: Dzrout on December 27, 2022, 07:30:40 AM
Was planning on using a Hafler DH-200
Title: Re: Moreplay Subwoofer output
Post by: Doc B. on December 27, 2022, 08:31:31 AM
Your best bet would be to look up the input impedance of the DH-200 and let us know what it is. Then we could ballpark a capacitor value for you to try. Note that a single cap will only create a first order crossover. Typically you want something more like a fourth order filter to effectively limit the upper frequency output of the subwoofer so it doesnt overlap too much with your main speakers.
Title: Re: Moreplay Subwoofer output
Post by: Dzrout on December 27, 2022, 10:54:54 AM
Thank you! Best I can find, it’s 22k. I really appreciate your help!
Title: Re: Moreplay Subwoofer output
Post by: Thermioniclife on December 27, 2022, 11:25:48 AM
If you want to be the cool kid on the block you could get a Nakamichi EC-204 electronic crossover and use low output to a sub amp and the high output to a main speaker amp. It has adjustable crossover points selected with switches from 10Hz to 310Hz for both the low and high outputs. I have and used one since the early 90's on both car and audio systems with great success. It is clean and quiet and has a S/N ratio listed as better than 105db. There are some on ebay for very good prices. It has a 10k input impedance with a 1k output impedance. They also made a 3 way xover also called the EC-302. So if the Moreplay can run into a 10k load this would work nicely for you. Just saying.
Title: Re: Moreplay Subwoofer output
Post by: Dzrout on December 27, 2022, 12:13:49 PM
I’ll check that out. I’ve had a heck of a time finding something passive.
Title: Re: Moreplay Subwoofer output
Post by: Doc B. on December 27, 2022, 12:32:32 PM
Higher order passives are going to have some losses and low pass filters are slightly more tricky to incorporate into an amp input than high pass filters. So an active crossover might be worth it. Or by the time you add that level of complexity maybe just get a dedicated subwoofer amp with the crossover built in instead.
Title: Re: Moreplay Subwoofer output
Post by: Thermioniclife on December 27, 2022, 02:12:50 PM
I hear you Doc but it's nice to send the lows as in this fellows case to the sub and run the main speakers above the xover freq. thus using the main amp with more efficiency due to the fact it does not have to reproduce the lows. I have not seen amplified subs that will accept low level input that output via low level just above the xover freq.to the mains. It's quite nice to have the control of the filter on the main speaker amp. Been there done that. Having said that it's just one old mans position on the matter. Perhaps an idea for BH to produce an active line level xover as proposed for your Jagers. Peace out, no hostility intended.
Title: Re: Moreplay Subwoofer output
Post by: Dzrout on December 27, 2022, 03:53:05 PM
I have a powered subwoofer that works. There are other ones out there that have a better crossover. I may go that route. But I was just thinking, it would be nice to just use whatever amp I have here.
Title: Re: Moreplay Subwoofer output
Post by: Doc B. on December 27, 2022, 04:05:44 PM
I'm really not trying to be contrary. Just suggesting different ways to skin this particular cat and offer some of my own experience. Any of the ways mentioned is a valid approach.
Title: Re: Moreplay Subwoofer output
Post by: 2wo on December 27, 2022, 06:00:34 PM
I get wanting to use an existing amp, l used a DH 200 Lin a similar role years ago. I would encourage you to look into an active crossover.. there're some DIY options out there as well as DSP...John
Title: Re: Moreplay Subwoofer output
Post by: Paul Birkeland on December 27, 2022, 07:38:39 PM
22K is not a particularly ideal input impedance for something like this.  You could get an inexpensive active line level subwoofer crossover or use a passive subwoofer crossover instead.
Title: Re: Moreplay Subwoofer output
Post by: Dzrout on December 28, 2022, 06:00:21 AM
Thank you for the help guys. I don’t mind getting an active crossover. I suppose at the frequency level, I’m not as worried about any added noise or distortion. I’ll see what I can find. Thank you again! I really appreciate all your knowledge!