80hz speakers require a higher crossover point?

[RandomMember321]

This is my first time posting, I just have a quick query really.

I've just bought a new pair of bookshelf speakers and was wondering if I need to adjust the crossover setting for them. 99% of the time I use my system for music only with the exception of the occasional film/movie playing through it. It's widely accepted that 80hz is a good minimum frequency to allow bookshelf speakers to play (as I increasingly read all over the net), but also I've seen people say that allowing speakers to play to their lowest specified frequency will put extra stress on the speakers. In the case of the speakers I've just purchased the lowest frequency response they play is 80hz, so would the need to cross them over any higher still apply to me?

Thanks.

 

[T7BSY]

Are you using a stereo amp or AV receiver? im guessing AV Receiver, in which case you only need to adjust the crossover if you have a sub, or for fine tuning, in normal circumstances you speakers will only produce frequencies its capable of, there will be no extra strain on the speaker but if you have a active subwoofer and set your av to 80hz then anything below that will be sent to the sub, this will reduce the workload on the receiver, if you have 5.1 then its best to set all you speakers large or small to 80hz or more if the speaker you have are not capable, some small surrounds speaker may have to be set to 100hz or even 120hz

 

[RandomMember321]

Hello, thanks for the reply.

My system is a 2.1 system with two stereo power amps (one for the main speakers and one for a passive sub woofer speaker), an active crossover and a stereo pre-amplifier. Before one of the kids messed around with the system and blew one of the previous main speakers, the main speakers were rated 50hz-20khz. The crossover has always been set to 80hz but I knew it was a safe bet as there was quite a margin before the lower limit of those speakers.

So are you suggesting it is safe to allow these new speakers to play their full rated frequency (80hz-20khz) without any problems?‎

Thanks again.

 

[RandomMember321]

BTW, I'm not that tech savvy so bare with me if I miss any vital points made due to me not understanding audio tech jargon lol

 

[BlueWizard]

Specifically what amp are you using?

Where you set the crossover depends on whether you or your amp have Bass Management.

There are three ways to integrate a Subwoofer into a Stereo system.

1.) Have a amp with Bass Management. This will set the crossover for BOTH the Front and the Sub. In this case you can set the crossover at any frequency within the range of both the Front and the Sub. Typically this is 80hz assuming that the Front speakers go a bit deeper than 80hz.

2.) Overlap the frequencies. For example if your Front speakers are rated down to 50hz, and you set the crossover at 80hz, then you will have an overlap between 50hz and 80hz, that will exaggerate that range. Sub only below 50hz, Front only above 80hz, and BOTH between 50hz and 80hz, but again, that exaggerates that overlap range. That's fine if you like exaggerated bass. Not so fine if you like clean smooth integration.

3.) Blending the Front and Sub. If in this example, the Front goes down to 50hz, then you set the Subwoofer to crossover at 50hz, that way the Front and Sub blend together. Then it is simply a matter of adjusting the the Volume Level of the Sub to best match the Front and your personal taste. But, if the Front are rated too low, say 40hz, many Subs can't be set that low.

This last method gives you the best and smoothest blend of Front and Sub. But since the Front speakers are using their natural roll off, the do not get any additional protection from being over-driven. However, if you like additional bass, rather than cranking the bass control on the Amp up, you can simply turn the Sub up. That eases the strain on the Front speakers.

Those are your options.

Steve/bluewizard

 

[RandomMember321]

Hello.

The amps are 2x Crown xls 1000 power amps, they do have some form of crossover management in them but I have a dbx stereo active crossover for that though.

The main speakers in question have a lower frequency limit of 80hz, according to the manual. I'm just in two minds whether it's advisable to allow them to play down to 80hz, since people say 80hz is good for bookshelf speakers (which these are), or whether it's not due to people saying that allowing speakers to play down to their lower limit puts excess stress on the speakers. The crossover has always been set to 80hz as my previous main speakers had a lower limit of 50hz, so there was a safe margin with them. No chance of the new ones digging much lower than 80hz I wouldn't imagine.

The sub is a passive sub so doesn't have its own filter. I think it was custom made at some point because I can't seem to find this exact unit online. It's a twin ported enclosure with a 12" Fane bass driver in it. It plays down to about 35hz but I limit it at 40hz as there's not much punch below that.

‎Thanks.

 

[ShanePJ]

If you have already selected an amplifier, speakers and woofer then it maybe to late.

If you purchase any good pair of speakers which do not accelerate the bass, then you'll find that they naturally fall away allowing your to create the perfect balance without excessive bass thus doing away with the need for an amplifier with a crossover feature. (Stereo only)

Look toward any amplifier, which uses the "neutrik connection (Rel Acoustics and MJ Acoustics are a couple) for subwoofer connectivity. This simple means that you can use your speaker terminatal outputs on your amplifier and without the need of using line out.

This is where the magic starts to happen.

As you're speakers naturally fall away with bass reproduction, you simply dial the level and gain of the woofer to match the audible level of your speakers, thus creating a seemless flow of sound.

When setting your system up correctly with a stereo configuration, you should never hear the woofer until you power it down and at this point, you should hear a smaller sound.

This is something I've been doing for about 18 years and when you get it right, it creates quite an enjoyable experience.

If your looking for a speaker and wish to keep them small then the Monitor Audio Radius 90 speakers together with the MJ Acoustics' Pro-50Mk3 is a sensational package.

Regards, Shane

 

[RandomMember321]

Hello.

I already have speakers and sub. The speakers are the Apart mask 4 and the sub as mentioned is a passive 12", what I believe to have been custom made by somebody at some point.

The sound is fine I'm happy with that. What I'm in two minds about is the crossover point. I understand (from things I've read at least) that 80hz is a favourable point to cross speakers over at, but on the other hand people also say don't allow speakers to play down to their lowest rated frequency as it can put strain on the speakers. Coincidentally, 80hz is the lowest rated frequency of the main speakers anyway, so would there be a need to cross them over any higher simply because 80hz is their lower limit?

I'm trying to explain this as clearly and to the point as possible but I'm not sure if I am.

Thanks.

 

[ShanePJ]

If you're happy with the sound and you can hear the full range of frequencies, then why are you looking to bring something in which could fundamentally alter the sound for the worse.

I have a firm policy, if it isn't broken, don't break it!

I'm guessing its curiosity and we all know what happened to the cat!

Regards, Shane.

 

[honestguvnor]

I already have speakers and sub. The speakers are the Apart mask 4 and the sub as mentioned is a passive 12", what I believe to have been custom made by somebody at some point.

The sound is fine I'm happy with that. What I'm in two minds about is the crossover point. I understand (from things I've read at least) that 80hz is a favourable point to cross speakers over at, but on the other hand people also say don't allow speakers to play down to their lowest rated frequency as it can put strain on the speakers. Coincidentally, 80hz is the lowest rated frequency of the main speakers anyway, so would there be a need to cross them over any higher simply because 80hz is their lower limit?

The main speakers have a small 4.5" midwoofer which will struggle to play 80Hz at standard levels (the level in a cinema) in a reasonable sized room. If the subwoofer is near the main speakers it is likely a higher crossover will sound noticeably cleaner.

 

[RandomMember321]

I think I'm going to disconnect the active crossover from the main amp/speakers, then set it to mono and just use it as a LP filter for the sub amp/sub woofer. Before I ever got my hands on any form of bass management, I always played stereo speakers at full frequency anyway and never damaged a speaker doing things that way...in fact, if anything it probably did make speakers sound even better over time.

Thanks for the replies it's much appreciated, and all information taken on board.

 

[BlueWizard]

If you are using a AV Receiver, the internal Setup Program will figure it out, or at least make a suggestion as to the most effective crossover. Generally, that will be some were between the low cut off of the Front Speakers, and about 20hz above the low cut off. So apparently, in your case, that would between 80hz and 100hz.

However, the AV Receiver Setup doesn't just go by the numbers, it actually measures the response in the room, and sets the crossovers accordingly.

Generally, crossing at the low end cut-off of the Fronts speakers is workable, but it puts a bit more stress on the Front speakers. Trimming 10hz to 20hz of their response makes the job of the Front Speakers Easier.

With 80hz rated speakers, I think probably 100hz would work best.

However, with a Stereo system, you have the THREE Options I outlined.

1.) Bass Management - which you may have some form of

2.) Overlap Frequencies -

3.) Blending the Front and Sub -

If can control the crossover yourself, then set it to 100hz from both Front and Sub.

The Crown XLS amp can be set to both High-Pass and Low-Pass at frequencies ranging from 50hz to 3000hz.

If you have a single passive Sub, that could be a problem, as you somehow need to blend the Left and Right channels together to get a combined signal for your Subwoofer.

However, the are Line Level Stereo to Mono converters, that will blend the Left/Right of Stereo into a pair of combined Left/Right Mono Signals.

go4products | Rakuten.co.uk Shopping: AUDIO CONVERTER STEREO/MONO

Since you only have one Sub, you would likely only use one channel of the Crown XLS that drives the Subwoofer.

Alternately, the Crown XLR has a BRIDGED mode (700w mono vs 215w for stereo), where the left and right channels of the amp are merge into one very big MONO channel. And apparently the Low-Pass and High-Pass still work in this mode.

That's all good. The bad part is that the internal filters on the Crown XLS are 24db/octave 4th order filters. That means the cut-off or the roll-off slopes is extremely steep, almost like brick wall. These are made for PA applications.

Likely the crossovers in your Active Crossover are the same 24db/octave, though they could be 18db/octave. Typically a Stereo system will have 6db/octave or 12db/octave crossovers. But ... you work with what you have.

I don't have the details on the Active Crossovers you have, so I can't speculate on them. But with the Crown amps and the Passive crossover, you would configure the system like this -

1- Crown XLS-1000 in Stereo (215w/ch) with about 100hz High-Pass crossover.

1- Crown XLS-1000 in Bridge Mono (700w) with about 100hz Low-Pass Crossover for the Sub.

To comment on the value of dbx stereo active crossover, I would need to know the exact model number. If this is a Speaker Management System rather than a Active Crossover, you have many more options for setting the crossovers and the crossover slopes.

Steve/bluewizard

 

[RandomMember321]

The crossover is a dbx 223s which has a LF Sum option to combine the two stereo low frequency channels to one mono channel. However I don't use this because I send a mono signal through the system strait from the preamp, so the entire music is mono anyway. I use mono simply because it's not a dedicated listening room just for me, it's the family living room so other people hear music on the system as well. And there's not actually any seating in the centre of the room between the speakers. I've had the dbx before I got the crown amps so I've just always preferred to use this rather than the crown crossover management system (I've never actually bothered to read the manual to an extent of finding out how simple or difficult it would be to use this function on the amps lol).

I'll give 100hz a try and see if it still sounds OK to me, if not I'll just proceed with my previous conclusion of using the crossover as a low pass filter for the sub woofer, and let the speakers play directly from the preamp source with no intervention from the dbx. As somebody else made reference to, I don't want to change the sound of the system by altering the crossover setting, I would hope I could find something which still sounded good, but gave me that bit of extra security that the main speakers weren't being over driven. With them being new I'm not familiar with them yet like I was with my previous speakers so I'm approaching with caution I guess.

Thanks. ‎